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287 Cards in this Set

  • Front
  • Back
Name one imidazole and its MOA:
Clotrimazole, miconazole, ketoconazole, econozole, voriconazole: inhibit P450 alpha demethylase
Name the class and MOA of Nystatin:
Polyene, ergosterol binding
Name calss and MOA of terbenafine and butenafine:
allylamines, squalene epoxide inhibition
Triazoles include:
Itraconazole, fluconazole
How does food affect absorption of itraconazole and griseofulvin?
increases absorption
How do H2 blockers and PPI's affect the absorption of itraconazole and ketoconazole?
decrease absorption
How does food affect bioavailability of terbenafine?
no effect
Which antifungal has been associated with CHF?
Intraconazole: median dose 300 mg daily (100-800); median time to onset 10 days (1-210 days), 58 cases reported over 10 yrs
Name 4 side effects associated with voriconazole:
photosensitivity, photoaging, AK/SCC, melanoma, porphyria(pseudo)
Echinocandins have what MOA and which target organisms?
B 1,3 glucans; Candida and aspergillus
What is the most common cause of Tinea capitis in US?
T. Tonsurans
what is the most common cause of Tinea capitis among arab and african immigrants?
T. Soudamense, T. Violaceum, M. Audouinii
what is the most common cause of Tinea capitis with pe exposure?
M. Canis
What are the causes of black dot ring worms?
T. Tonsurans >> T. Violaceum
What are the fluorescent ectothrix fungi?
"Cats And Dogs Fight and Growl Sometimes M. canis M. audouinii M. distortum M. ferrugineum and sometimes M. gypseum T. schoenleinii"
What is the treatment for highly inflammatory kerion?
Systemic steroids for a short period +antifungal
Name the two dermatophyte that do not involve the hair?
E. floccosum; T. concentricum
What is the most common cause of Tinea capitis in Iraqi children?
T. verrucosum (varr (war) in iraq)
What is the most common cause of Tinea capitis in south central Asia?
T. violaceum
What is the most common cause of Tinea capitis in East Asia?
T. violaceum & M. ferrugineum
What is the most common cause of Tinea capitis in Australia?
M. Canis
What is scultulae?
Cup-shape crust pierced by a central hair in Favus
what is the most common cause of Favus?
GALDERMA: Primarily T. schoenleinii, occasionally T. violaceum, M. gypseum
What is the fluorescent substance in flourescent positive tinea capitis?
Petridine
T. tonsurance needs Thiamine to Grow. True or False?
True.
What is the most comon antifingal used in children?
Griseofulvin
what is the dose and administeration method of griseofulvin to children?
ultramicronized form 10mg/kg/day crush and give with ice cream
what is theduration of treatment with griseofulvin for tinea capitis?
2-3 months or at least 2 weeks after negative cultures
What is the best antifungal for trichophyton infections?
Terbinafine 3-6 mg/kg/day 1 -4 weeks
What serious side effect of Itraconazole has limited its use?
Heart failure
Which one of Dermatophytes causing tinea capitis will persist until adulthood if not treated?
T. tonsurans
The id reaction from tinea capitis responds rapidly to topical steroids. True or False?
False. It is refractory to toical steroids, but clears rapidly after the treament of dermatophyte
What is erysiplas-like dermatophytid?
Id reaction, large erysiplas-like plaque on the shin of the same side as tinea pedis; this responds to systemic steroids and treatment of fungus
what is the causative organism in deep type of tinea barbae?
T. Mentagrophyte and T. verrucosum
what is the causative organism in superficial crusted type of tinea barbae?
T. violaceum and T. rubrum
How do you distinguish sycosis vulgaris from Tinea sycosis?
Tinea does not involve the upper lip and is unilateral
Tinea faciei in hog farmers is commonly due to what organism?
Microsporum nanum
What is tinea faciei most commonly misdiagnosed as?
Lupus; tinea faciei is photosensitive, can demonstrate some reactants on DIF, can show vacuolar interface on histology, and may be annular and minimally scaly
Tinea faciei mistreated with topical steroids may develop what?
Fungal folliculitis
Which zoophilic dermatophyte can cause epidemics of widespread inflammatory tinea corporis?
T. mentagrophytes related to Southeast Asian bamboo rats
What are the three most common causes of tinea corporis in US?
T. rubrum, T. mentagrophytes, M. canis
Which topical antifungals can be used once daily for tinea corporis?
Econazole, ketoconazole, oxiconazole, and terbinafine
What can improve absorption of griseofulvin?
Give with whole milk or ice cream
What organisms most commonly cause fungal folliculitis (Majocchi's)?
T. rubrum and T. mentag
What pre-disposing factor most commonly leads to fungal folliculitis?
Treatment with steroids
What is tokelau?
Tinea imbricata
What does "imbricata" mean?
Imbrex means shingle; lesions are concentric rings with shingle-like scales
Causative fungus in tinea imbricata?
T. concentricum
Treatment most effective for tinea imbricata?
Terbinafine 250 daily for 4 weeks
How to differentiate Candidal groin infection from tinea cruris?
Candida is moister, more inflammatory, and has satellite macules or pustules
Most common organism in tinea pedis?
T. rubrum
Name three distinct ways that T. mentag presents on feet
Multilocular bullae on plantar arch and sides of feet and heel; erythema and desquamation between toes; white superficial onychomycosis
What changes occur on DTM media when exposed to dermatophytes?
Alkaline metabolites changes color from yellow to red
What organism is the most common cause of onychomycosis?
T. rubrum
What type of onychomycosis may be an indication of HIV infection?
proximal subungual onychomycosis (T.rubrum, T, megninii)
What test is most sensitive in making a diagnosis of onychomycosis?
PAS on histopathology. More sensitive than culture or KOH)
What differentiates onychomycosis from nail psoriasis?
presence of pits, oil spots, salmon patches and onycholysis in psoriasis
What differentiates the onychomycosis from LP nail involvement?
dorsal pterygium, oral mucosal lesions in LP
What differentiates onychomycosis from nail findings in eczema?
involvment of the proximal nail fold in eczema
What group is at high risk of developing complications of onychomycosis?
Diabetics and pts with peripheral neuropathy
What may be associated with a high risk of failure in treating onychomycosis?
presence of a dermatophytoma within the nail (yellow streaks within nails)
What type of onychomycosis is always a sign of immunosupression?
Candida onychomycosis
A patient with coronary artery disease and CHF would like to pursue treatment for longstanding onychomycosis. What antifungal treatment in relatively contraindicated in this patient?
Itraconazole
In a patient with no predisposing factors, evidence of oral thrush should prompt what evaluation?
HIV
What features on histopathology sections with PAS stain help differentiate dermatophyte from candida?
candida should have pseudohyphae which are vertically oriented
What conditions may predispose to oral candidiasis?
recent oral antibiotic use, dry mouth (saliva inhibits candida growth)
T/F: Gentian Violet, Castellani paint and boric acid are all agents than can be used for candida treatment.
True. They are all older agents.
T/F: It is normal for healthy infants to have thrush.
True (vs older kids and adults, where it is usually indicative of Antibiotic rx or immunosuppression)
T/F: Dry mouth predisposes to candida infection (thrush).
True. Saliva inhibits growth of candida
How commonly is thrush seen in full-blown AIDS?
"Always. Thrush is commonly the 1st presentation of HIV. ANY adult with thrush and no obvious explanation warrants HIV test
How is thrush usually treated in infants?
Oral nystatin
How is thrush usually treated in adults?
"Mild: Clotrimazole troches, More severe: Fluconazole 150mg x 1 dose. HIV: Fluconazole 200mg/day"
What is the preferred treatment for perleche?
"Anticandidal creams + mid-potency steroid -Combination therapy more rapidly effective -If severe, recalcitrant, may consider filler injection into depressed sulcus"
T/F: Candida albicans is commensal organism in the vaginal tract.
True. When overgrowth occurs this leads to "candida infection"
Name 2 general drug classes that predispose to candidal vulvovaginitis.
Antibiotics, Tamoxifen
What is the preferred treatment for candidal vulvovaginitis?
"Fluconazole 150mg x 1 dose Topicals may work too, if mild If candida glabrata, may be refractory to azoles. Consider topical boric acid, topical amphotericin B or flucytosine
What clinical clue helps distinguish tinea cruris from candidal intertrigo?
Candidal intertrigo has less scaling and more fissuring. Also has pustules adjacent to plaques.
What is the preferred treatment for candidal intertrigo?
"Anticandidal creams + mid-potency steroid Combination therapy more rapidly effective May also use Castellani paint
An infant with recurrent diaper candidiasis may benefit from _______ in addition to the usual topical antifungal treatments.
Oral nystatin (to decrease gut colonization)
What is the usual presentation of congenital cutaneous candidiasis?
"Widespread red macules arise a few hours after delivery in a pregnancy complicated by premature rupture of membranes in a female with c.albicans in the vaginal canal. These red macules progress to papulopustules. Oral cavity and diaper area are spared, in contrast to the usual type of acquired neonatal infection. Rare systemic involvement occurs, usually only in infants <1500gm. Treatment = systemic antifungals"
How does perianal candidiasis present?
Erythema, oozing, maceration, severe pruritus and burning sensations. May not see satellite lesions
A patient with longstanding atopic dermatitis develops redness, swelling and tenderness of the proximal nailfolds, as well as brownish discoloration of the nail plate. The patient does a lot of wet-work. What is the most likely diagnosis?
"Candidal paronychia. Ass'd with atopy, wet work, diabetes"
What is the preferred treatment of candidal paronychia?
"Avoidance of wet work and irritants + topical antifungals + topical steroids Like most candidal skin infections, combination of topical antifungals + steroids is more effective than either alone If topicals fail, use fluconazole orally"
A diabetic patient has an oval shaped area of macerated skin with fissures and a red base in the 3rd finger webspace, extending onto the sides of the fingers. What is the most likely diagnosis?
"Erosio interdigitalis blastomycetica Ass'd with DM, wet work 3rd to 4th webspace most common on hands 4th webspace most common on feet"
T/F: The term Chronic mucocutaneous candidiasis comprises a heterogeneous group of patients with either inherited or sporadic defects.
"True. Candida infection is limited to mucosal surfaces (diffuse plaques, perleche, lip fissures), skin (horn-like hyperkeratotic plaques or granulomatous lesions) and nails (hypertrophic with paronychia) Onset before age 6. Onset in adulthood may be presenting sign of thymoma. Underlying defects are unknown but thought to represent selective defect in immunity to candida with decreased Th1 response. Decreased IL-12, markedly increased Th2 cytokines (IL-6 and IL-10)"
Patients with chronic mucocutaneous candidiasis have unknown defects that lead to susceptibility to candida. Th1 cytokines are _______ (increased/decreased).
Decreased Th1. Increased Th2. CMC has decreased Th1 and increased Th2 profile.
A 5 year old patient has diffuse superficial ulcers and pustules in the oral cavity, perleche, lip fissures, thickened dystrophic nails with paronychia and hyperkeratotic papules and plaques scattered about the cutaneous surface. What is the treatment of choice?
"The diagnosis is chronic mucocutaneous candidiasis. Systemic azoles are the treatment of choice, usually given in higher doses for extended durations. Cimetidine may also help"
T/F: Systemic candidiasis only arises in the setting of immunosuppression.
True. Highest risk groups: leukemia/lymphoma, AIDS, malnourished, immunosuppressive agents, prolonged use of indwelling catheters, drug abusers.
How does chronic mucocutaneous candidiasis differ from systemic candidiasis?
CMC is a non-fatal disease that only affects mucocutaneous surfaces. In contrast, systemic candidiasis is a disseminated disease with severe internal involvement with high mortality rate (30-50%!)
A hospitalized patient with AML develops a fever of unknown origin with proximal muscle weakness and a disseminated maculopapular exanthem, with prominent involvement of trunk and extremities. Fungal culture grows candida. What is the treatment of choice?
"Amphotericin B = Gold Standard -Despite adequate treatment, mortality remains very high (30-50%)"
A hospitalized patient with AML develops a fever of unknown origin with proximal muscle weakness and a disseminated maculopapular exanthem, with prominent involvement of trunk and extremities. Fungal culture grows candida. What is the mortality rate?
Very high (30-50%) despite adequate treatment
Candidids are less common than dermatophytids. When candidids do occur, what are the 2 most common presentations?
Erythema annulare centrifugum or chronic urticaria
What commonly-used antibiotic class is felt to most strongly predispose to iatrogenic candidiasis of mouth, GI tract, perianal area and candidal vulvovaginitis?
"Tetracyclines Treat with Fluconazole 150mg x 1 dose"
Systemic candidiasis is characterized by disseminated maculopapular exanthem and what muscle finding?
Proximal muscle weakness. This is supposed to be a helpful clue to the diagnosis. Systemic candidiasis is a rare complication that usually only arises in immunocompromised pts, and has a high mortality (30-50%) despite treatment with Amphotericin B.
In a patient who has undergone bone marrow transplanation, there is a risk developing systemic candidiasis, which has a mortality rate of 30-50%. What is used as prophylaxis status post BMT?
Fluconazole
What yeast-like fungus used commercially as a maturing agent for cheese may act as an opportunistic pathogen and produce mucocutaneous disease resembling candidiasis?
"Geotrichosis Part of natural flora of milk that is used as maturing agent for cheese. Mucocutaneous disease with erythema, pseudomembranes, mucopurulent sputum like thrush Dx: KOH and culture on Saboraud dextrose agar Rx: Oral nystatin or mycostatin"
What is the infectious agent in tinea nigra?
"Hortaea werneckii (formerly Phaeoannellomyces weneckii) Yeast-like organism found in hot, humid climates Produces brown-black spots on palms and soles. Mistaken for acral nevi. Dx: KOH and culture Rx: Topical azoles and allylamines"
What is the treatment of choice for tinea nigra?
Topical azoles and allylamines
A patient from South America presents with dark, pinhead to pebble-sized formations on the hairs of the scalp, eyebrows, lashes and beard. KOH of the node-like masses shows numerous oval mycelia and acrospores. What is the diagnosis?
Black Piedra
A patient from South America presents with dark, pinhead to pebble-sized formations on the hairs of the scalp, eyebrows, lashes and beard. KOH of the node-like masses shows numerous oval mycelia and acrospores. What is the causative infectious agent?
Piedra hortai
What is the cause of white piedra?
"T.beigelii, T.inkin, T.asahii Unlike black piedra, occurs in temperate climates Syndergistic corynebacterial infection usually present. T.beigelii also causes onychomycosis"
T/F: The infectious agent responsible for white piedra may also cause onychomycosis
"True. T.beigelii is causative agent"
T.asahii may cause what diseases?
White piedra, onychomycosis, and DISSEMINATED cutaneous infections in immunocompromised patients
Which infectious agent may cause white piedra and disseminated disease in immunocompromised patients?
"T.asahii White Piedra: T.beigelii, T.inkin, T.asahii Onychomycosis: T.beigelii, T.asahii"
What agent is responsible for white piedra of the pubic hairs?
T.inkin (not T.beigelii or T.asahii…these 2 can cause onychomycosis though)
What is the treatment of choice for piedra?
"Cutting the hairs. Alternatively: Black Piedra: Oral or topical lamisil White Piedra: Oral itraconazole, azole creams, ciclopirox, Castellani paint"
What is the causative agent in tinea versicolor?
"M.furfur The yeast phase of M.furfur is called Pityrosporum orbiculare Part of the normal follicular flora"
T/F: M.furfur is part of the normal follicular flora and only produces skin lesions when they grow in the hyphal phase.
"True. Most common during summer and favors oily areas of skin (sternal chest, abdomen, back, neck, intertriginous areas"
In infants and immunocompromised patients, tinea versicolor may arise in unusual anatomic locations, such as ______ and ____.
"Face and scalp Also palms and soles and penis"
How long does the hypopigmentation from tinea versicolor persist?
Weeks to months
What is seen on KOH of tinea versicolor?
hyphae and lots of variably-sized spores
T/F: For treatment of tinea versicolor, a single dose of Itraconazole 400mg is as effective as the standard 7 day course of Itraconazole 200mg daily.
"True. Also, Fluconazole 400mg x 1 dose very effective Lamisil is effective topically but not orally. Twice daily application of all topicals is more effective than once daily application"
What are the 3 diagnostic criteria for Pityrosporum Folliculitis?
"Yellow-green fluorescence with Woods lamp, Pityrosporum yeast in biopsy or smears of papules, prompt response to antifungals Favors upper back. Small itchy papules and pustules. More common in transplant pts and pts on tetracyclines for acne"
What demographic group is at highest risk for pityrosporum folliculitis?
Transplant pts and pts on Tetracyclines for acne
What is the treatment of choice for pityrosporum folliculitis?
Fluconazole 400mg once, followed by prophylaxis with monthly selenium sulfide or econazole cream
How are deep fungal infections usually acquired?
"Usually inhalation, leading to systemic infection with occasional cutaneous findings. Therefore, CXR is required in all suspected cases Less commonly, punture wounds may lead to verrucous lesions + secondary lymphangitis"
What is the infectious agent responsible for Valley Fever?
"Coccidiodes immitis Inhalation leads to low grade fever and flu-like symptoms 10 days later, with generalized nonspecific morbilliform exanthem. Later, 30% develop allergic symptoms such as erythema nodosum or erythema multiforme 60% of pts are entirely asymptomatic
A white female inhales coccidioides in California. 10 days later she develops a flu-like illness with morbilliform exanthem. A few weeks later she gets tender nodules on the shins and buttocks. Is this a favorable or unfavorable sign?
Erythema nodosum occurs in 30% of pts a few weeks after coccidioides infection. It usually occurs in whites and is associated with a good prognosis.
A patient inhales coccidioides immitis and develops flu-like symptoms. What skin finding is considered a good prognostic sign?
Allergic skin reactions (usually Erythema nodosum). Usually occurs a few weeks after onset of pulmonary symptoms.
Coccidioides is usually a self-limited infection. A small percentage progress to the chronic, progressive, disseminated form. Immunosuppressed and AIDS patients are one group at increased risk. What are other risk factors?
"Race: Blacks, Filipinos, Vietnamese, Native Americans Also Blood Types B or AB"
What blood types are associated with increased risk of disseminated coccidioides?
Blood type B or AB
What racial groups are at increased risk for disseminated coccidioides?
"Blacks, Filipinos, Vietnamese, Native Americans Note: Whites more commonly develop allergic skin symptoms (erythema nodosum) aqnd have better prognosis"
A patient develops Valley Fever. What is the risk of developing disseminated coccidioidomycosis?
"less than 1% Target organs: MSK system, CNS, skin"
How often does skin disease occur in disseminated coccidioidomycosis?
"20% Verrucous nodules or abscesses on face. May be molluscum-like in AIDS (but cryptococcus is more commonly the cause of these type of lesions)"
A biopsy is performed on a lesion and shows coccidioides on H&E. Without further history, would you suspect that this represents primary cutaneous coccidioidomycosis or disseminated coccidioidomycosis?
Skin disease should always be considered to be a manifestation of systemic (disseminated) coccidioidomycosis rather than primary cutaneous disease, unless there is an awesome history for direct skin inoculation (splinter seen in biopsy or clear-cut history).
Although it is much less common than disseminated coccidioidomycosis, you are required to know about primary cutaneous coccidioidomycosis for boards purposes :) A patient in California gets a coccidioides-infested splinter in the extremity. How would you expect him to present clinically?
1-3 weeks after inoculation, a nodule appears at the site +/- ulceration. Then sporotrichoid spread along lymphatics. Treatment = Amphotericin B or azoles
In the environment, where is coccidioides found and what leads to epidemics?
"C.immitis is found in soil and vegetation, especially in the burrow holes of rodents. Therefore, when the soil is disrupted (construction, earthquakes, etc) to a depth of 20cm or more, coccidioides is released into the air and epidemics occur. Note: a large outbreak occurred after the Northridge earthquake"
Histologically coccidioides spherules may vary in size from 5-200 microns (avg. size 20 microns). Endosporulation can occur and the organism can resemble Rhinosporidium. How do you differentiate these 2 organisms?
Rhinosporidium always has a small central nucleus and is larger in size.
Why should you not attempt to culture coccidioides in your Derm office?
It is readily grown at room temperature and releases highly infectious filaments of barrel-shaped arthrospores.
T/F: Almost all California natives have been infected with coccidioides at some point in time.
True. But 60% are entirely asymptomatic. The other 40% may get a low-grade flu-like illness only. Only half of these people get any skin findings, usually erythema nodosum. Less than 1% of all patients develop disseminated coccidioidomycosis.
True/False: New residents to California have a high likelihood of becoming infected with Valley Fever within 6 months of arrival.
True. But 60% are entirely asymptomatic. The other 40% may get a low-grade flu-like illness only. Only half of these people get any skin findings, usually erythema nodosum. Less than 1% of all patients develop disseminated coccidioidomycosis.
What other deep fungal disease most closely mimics the skin findings of coccidioidomycosis?
Blastomycosis. Both can look verrucous or plaque like (resembling mycosis fungoides). Need serologic testing or biopsy to distinguish.
What blood tests can be used to diagnose recent coccidioides infection?`
"Serologic tests: precipitin, enzyme immunoassay (EIA), immunodiffusion, latex agglutination tests. All permit detection of coccidioidal IgM in early (1-2 weeks after infection) disease. For detection of later stage disease, need complement fixation test"
Coccidioides involving the skin can be very difficult to distinguish from blastomycosis. What are 2 ways to distinguish these diseases?
"Biopsy or serologic testing. Serologic tests: precipitin, enzyme immunoassay (EIA), immunodiffusion, latex agglutination tests. All permit detection of coccidioidal IgM in early dz (1-2 weeks after infection). For detection of later stage cocci, need complement fixation test"
What are the treatments of choice for coccidioidomycotic meningitis and progressive non-meningitic coccidioidomycosis?
"-Meningeal Cocci: IV and intrathecal Amphotericin B required If no meningeal involvement, may use Amphotericin B, Fluconazole, Itraconazole, Voriconazole or Caspofungin"
T/F: Histoplasmosis is caused by inhalation of airborne spores and the organisms remain confined to the lungs in almost all cases (ie, there is no dissemination to non-pulmonary organs).
"True. Dissemination to other organs only occurs in 1/2000 cases, and usually only people with weak immune systems. However, please note that a large number of pts with acute pulmonary histo develop ""allergic skin manifestations"" (erythema nodosum and erythema multiforme), as is the case in coccidioidomycosis."
Histoplasmosis infection rarely (1/2000 cases) spreads to involve organs other than the lungs. In disseminated histoplasmosis, is the skin or mucous membranes more commonly affected?
Mucous membranes >>> skin
T/F: Primary pulmonary histoplasmosis usually causes a chronic penumonitis and unlike coccidioidomycosis infection, does not lead to allergic skin findings such as EN and EM.
False. Primary pulmonary infection is usually a mild self-limited lung disease that only becomes chronic in patients with pre-existing emphysema. Allergic skin findings occur commonly in coccidioidomycosis (20-30%) and acute histoplasmosis (10%) infections.
Are you more likely to see allergic skin findings (such as erythema nodosum) in the setting of acute coccidioides or histoplasmosis infection?
"Coccidioides (20-30%) vs histoplasmosis (10%) Note: EM may also be seen in both"
What are the 4 forms of histoplasmosis infection?
"Primary Pulmonary Histo: most common manifestation, mild self-limited pneumonitis Progressive Disseminated Histo: immunosuppressed pts, involves RES, GI/GU, heart, mucous membranes > skin. Mucosal ulcerations + granulomas of oropharynx is the MOST common finding. Perianal dz also seen. Purpura may be seen in kids just prior to death, and is due to severe involvement of the RES. Primary Cutaneous Histo: Very rare; presents as chancre on penis African Histo: caused by Histoplasma duboisii, affects skin much more often than American form"
What type of patients develop progressive disseminated histoplasmosis?
"Immunosuppressed pts mostly: leukemia, lymphoma, AIDS, transplant pts, people on long term steroids or low dose Methotrexate (for psoriasis or lupus). 20% have no identifiable risk factor"
What commonly used dermatologic medications place patients with psoriasis or lupus at risk for disseminated histoplasmosis?
Low dose methotrexate, systemic steroids
What is the most common mucocutaneous lesion in progressive disseminated histoplasmosis?
"Mucous membranes (20%) are far more commonly involved than skin (6%). Most common mucosal lesions are ulcerations and granulomas of the oropharynx. Second most common is perianal ulcers or plaques. Skin disease is rare and highly variable appearing: umbilicated papules, plaques, cellulitis, ulcers."
What percentage of patients with disseminated histoplasmosis develop mucous membrane vs. skin lesions (excluding allergic skin findings such as EN and EM)?
20% develop mucosal ulcers and granulomas in mouth and perianal area. 6% develop skin lesions with variable morphology.
A young child with leukemia develops multiple mucosal ulcers a few weeks after going into a bat-filled cave in the Ohio river valley area. He develops purpura. What is the diagnosis and the significance of the purpura?
Progressive systemic histo. Purpura is the most common skin manifestation in kids and signifies impending death due to severe involvement of the reticuloendothelial system.
How does primary cutaneous histoplasmosis present?
Very rarely seen. Presents as chancre on penis, ?likely secondary to anal sex with someone who had it on their perianal area
How does African Histoplasmosis differ from the american form?
Caused by Histoplasma duboisii, skin much more commonly involved (both allergic skin dz and infiltrative dz), bones commonly affected with overlying cold abscesses on the skin, organisms much larger (13 microns vs 3 microns) and found within multinucleated giant cells rather than individual macrophage
What is the cause of histoplasmosis?
Histoplasma capsulatum
Where is histoplasma capsulatum found in the environment?
It is a soil saprophyte, commonly in bird and bat feces, most prevalent in Ohio and Mississippi River valleys
What does histoplasmosis capsulatum look like in skin biopsies?
2-3 micron round, encapsulated yeast within macrophages. Lack kinetoplast, evenly distributed throughout cytoplasm (vs Leishmaniasis)
How does a skin biopsy from a patient with African Histoplasmosis look different than one from the american variant?
African Histo: larger organisms (13 um vs 3 um), more multinucleated giant cells containing organisms
T/F: Transmission of pulmonary histoplasmosis occurs via person-to-person spread.
False. The spores are released from the soil, bird and bat feces and then inhaled.
What locations in the USA are classically associated with histoplasmosis?
Ohio and Mississippi river valleys
What is the best diagnostic test for histoplasmosis?
"Urinary ELISA Serologic testing is not very good since it requires a normal immune system, and most pts with disseminated histo have weak immune systems"
What is the treatment of choice for histoplasmosis?
"-Most cases: observation Moderate dz in immunocompetent pt: Amphotericin B or Itraconazole Severe dz or ANY immunosuppressed pt: Amphotericin B required"
Cryptococcus infection remains localized to the lungs in 90% of cases. When it does spread to other organ systems, which one is most commonly affected?
"CNS and skin Dissemination in AIDS occurs very commonly, 50%"
How severe is initial cryptococcal lung infection, usually?
Extremely mild. May be detected by CXR. However there are some cases of lung dz causing death
What is the most common cause for mycotic meningitis?
Cryptococcus. Presents as hallucinations, vertigo, headache, nausea, seizures, ocular HTN
T/F: The incidence of skin disease in cryptococcus is 10% in healthy patients but LOWER in HIV pts.
True!
What is the most common anatomic location for cryptococcus skin disease?
"Head and neck. Like histoplasmosis, the skin lesions are polymorphous, except in AIDS, where molluscum like papulonodules are the most common presentation"
T/F: Anytime you encounter a patient with cryptococcus seen on skin biopsy, you should assume it represents disseminated disease.
"True. Primary inoculation cryptococcus is exceedingly rare and requires a foreign body (splinter) seen on biopsy or a clear history of implantation of foreign body. Risk factors for primary inoculation crypto = outdoor activities and exposure to bird droppings"
What is the causative agent of cryptococcemia?
"Cryptococcus neoformans Budding yeast in tissue with prominent capsule that stains with mucicarmine, methylene blue and alcian blue. Fontana Masson stains melanin in the yeast very well."
Where is cryptococcus found in the environment?
Large cities with pidgeon droppings! Also, soil, dust.
What percentage of AIDS pts develop disseminated cryptococcal infection?
50%
What is the test of choice for diagnosis of cryptococal infection?
Latex slide agglutination test
What is the standard treatment for severe cryptococcal infection?
"IV Amphotericin followed by oral Fluconazole Flucytosine also added sometimes for meningitis"
What is Gilchrist's disease?
North American Blastomycosis
T/F: Gilchrist's disease is caused by dissemination of fungal elements that were initially introduced into the body via inhalation.
True. Blastomycosis is a primary pulmonary disease that most commonly remains confined to the lungs but may spread to the skin > bones (ribs, vertebrae).
What are the 2 most common sites of dissemination of blastomycosis?
"#1 Skin (80% of disseminated cases) #2 Bones (ribs, vertebrae) #3 Other organs (CNS, RES, GU)"
T/F: Cutaneous blastomycosis occurs commonly as a result of direct inoculation.
False. Skin disease is almost always the result of dissemination
What is the causative agent in blastomycosis?
"Blastomyces dermatitidis Found in soil and animal habitats"
What does the biopsy of blastomycosis show?
"Marked pseudoepitheliomatous hyperplasia + neutrophilic abscesses and giant cells. Organisms are thick walled yeast 5-7 um in diameter, broad-based budding Pearl: Organisms easiest to see within giant cells or intraepidermal abscesses"
What parts of the USA have high rates of blastomycosis infection?
"Ohio and Mississippi river basins Mississippi is most common state"
Is there a male:female difference in blastomycosis infection rate?
"Males:Females 6:1 Outdoor activity is huge risk factor, especially Beaver Lodges!"
Beaver lodge exposure and dog bites may elevate the risk for acquiring which deep fungal infection?
"Blastomycosis Dogs infected with pulmonary blastomyces can spread dz via bite. Beaver lodges are hot-spots for this fungus"
Cutaneous blastomycosis most closely resembles what other diseases?
"-Halogenoderma: usually more acutely inflammatory. Serum bromine and iodine levels help DDx TB verrucosa cutis: more gradual, less extensive"
What is the treatment of choice for blastomycosis?
"Itraconazole x 6 months Mnemonic: Makes sense that you treat less aggressively (ie, not Ampho B) than most other deep fungal infections, since skin is the most commonly affected organ in disseminated dz, rather than more vital organs"
T/F: Paracoccidioidomycosis involving the skin is almost always a sign of disseminated dz.
True.
What is the most common dermatologic manifestation of paracoccidioidomycosis?
Papules and ulcers in the mouth (gingivae > tongue and lips), progressing over time to destroy face. Lymphangitic spread may be seen after mouth lesions.
What is the cause of South American Blastomycosis?
Paracoccidioides brasiliensis
What do biopsies of South American Blastomycosis show?
Pseudoepitheliomatous hyperplasia + abscesses +/- ulceration. Round cells 10-60 um with multiple buds resembling "mariner's wheel"
In what countries does paracoccidioidomycosis occur most commonly?
Brazil, Argentina, Venezuela.
What demographic is at greatest risk for developing South American Blastomycosis?
Laboring males in Brazil or Venezuela (M:F = 15:1, due to 17 B-estradiol inhibition of mold-to-yeast transformation)
What is the treatment of choice for South American Blastomycosis?
"Itraconazole x 6 months Mnemonic: Same Rx as North American Blastomycosis"
A person gets a thorn or cat scratch of the hand and develops a small nodule that self-resolves. A few weeks later he develops painless, ulcerating nodules along the draining lymphatics. What is the infectious agent responsible for this infection?
Sporothrix schenckii
What are the 3 clinical presentations of sporotrichosis?
"#1 Regional Lymphangitic sporotrichosis (75%) #2 Fixed cutaneous sporotrichosis (20%) #3 Disseminated (5%): ass'd with EtOH abuse, immunosuppression, diabetes"
How does Fixed Cutaneous Sporotrichosis present clinically?
"Solitary nodule, plaque or ulcer on the face, WITHOUT regional lymphangitis. May also resemble rosacea Ass'd with increased host immunity, smaller inoculum"
T/F: Disseminated sporotrichosis has bone or joint involvement in almost all cases
True.
Sporothrix Schenckii is a dimorphic fungus. At which temperature does it grow in the yeast form?
"Room temp = mold form 37 degrees = yeast form"
T/F: Cigar shaped yeast are rarely seen in american cases of sporotrichosis but are common in Asian forms.
True.
What are common sources for sporotrichosis?
Rose bushes, barberry shrubs, sphagnum moss, carnations, straw, cat claws, insect stings
T/F: In cats, sporothrix schenckii produces disseminated disease commonly.
True. This may be why cats can spread the disease to humans via cat scratches.
Sporotrichoid spread is defined by the presence of a nodule or ulcer with accompanying nodules along the draining lymphatics. Although tularemia is sometimes included on the "NO SALT" DDx for sporotrichoid spread, it should not be, technically speaking. Why not?
TB, cat-scratch dz, tularemia, glanders, melioidosis, LGV, and anthrax are all better classified as "ulceroglandular syndromes" since they have an ulcer with REGIONAL ADENOPATHY (vs ulcer + NODULES along the lymphatics)
An alcoholic, diabetic, HIV+ gardener gets stuck with a rose thorn and develops a nodule at that site that ulcerates then resolves. A few weeks later he develops nodules along the draining lymphatics. What is the DDx for lymphangitic (aka sporotrichoid) spread?
"Sporotrichosis, Atypical mycobacteria, leishmaniasis, nocardiosis all produce sporotrichoid spread = nodule/ulcer + NODULES along the lymphatics Sporotrichoid spread is NOT the same as ""Ulceroglandular Syndrome"" (TB, cat cratch dz, tularemia, glanders, melioidosis, LGV, anthrax) which is characterized by an ulcer with REGIONAL ADENOPATHY"
What is the treatment of choice for sprotrichosis?
"Itraconazole x many months SSKI x 3 months may be used for cutaneous forms. Not usable in pregnancy, may cause flare of psoriasis or DH Hot packs may also kill Sporothrix since it cannot survive at temps > 38.5C (101 F)"
T/F: Chromoblastomycosis usually arises as result of direct inoculation into skin.
True. Thus, lower extremities are most common site. Begins as small papule or verrucous growth on foot, then spreads to form satellite lesions
What is the most common anatomic site for chromoblastomycosis?
Foot, since it is acquired through direct inoculation
What is the classic demographic group affected by chromoblastomycosis?
4:1 Males; farmers (75% of cases); bare-footed farm workers
How rapidly does chromoblastomycosis progress?
"Very slowly, over decades. There is an average 15 yr lag time from onset of first warty lesions on foot to diagnosis. SCC may develop at longstanding sites"
What are all the fungi that can cause chromoblastomycosis?
"Most Common = Fonsecaea pedrosoi Others: Phialophora (may also cause phaeohyphomycosis or mycetoma), Fonsecaea compacta, Cladosporium, Rhinocladiella, Exophiala (may also cause phaeohyphomycosis or mycetoma)"
T/F: Patients may have concurrent chromoblastomycosis and mycetoma or invasive phaeohyphomycosis.
"True. There is overlap with some of the organisms (Exophiala jeanselmei, Phialophora verrucosa) Cases of ""chromoblastomycosis"" with CNS involvement are probably better classified as invasive phaeohyphomycosis since there were hypahe seen on these biopsies"
What is seen on biopsy of chromoblastomycosis?
"Pseudoepitheliomatous hyperplasia + intraepidermal abscesses + dense dermal granulomatous inflammation + Medlar bodies (sclerotic bodies, copper pennies) Melanin present"
What distinguishes chromoblastomycosis from invasive phaeohyphomycosis on biopsy?
Presence of sclerotic bodies rather than hyphae
What demographic is at greatest risk for developing South American Blastomycosis?
Bare-footed male farmworkers. Very difficult to get this disease if you wear shoes! Fortunately, dissemination is rare, and only after decades is SCC likely to arise at affected sites
T/F: Chromoblastomycosis is easy to treat with systemic antifungals.
False. Itraconazole or oral lamisil may be effective in some pts but many require surgical excision (for small lesions) or foot amputation (for larger lesions)
T/F: Tinea nigra and alternariosis are both classified as superficial phaeohyphomycosis.
True.
What organism is the most common cause of phaeohyphomycotic cysts?
Exophiala jeanselmei
What are the 3 forms of phaeohyphomycosis?
"1) Superficial: T.nigra, alternariosis 2) Pheaohyphomycotic cyst: E.jeanselmei 3) Systemic: immunocompromised pts, Bipolaris spicifera or Scedosporium prolificans, very high mortality rate"
Many black molds cause phaeohyphomycosis. Name some.
Exophiala jeanselmei (#1), Wangiella, Alternaria, Curvilaria, Bipolaris, Phialophora, Cladosporium, Wallemia, Chaetomium
Some fungi may cause either phaeohyphomycosis and chromoblastomycosis, depending on the host. Name some of these fungi.
Phialophora verrucosa, E.jeanselmei (both may also cause mycetoma)
What fungi can cause chromoblastomycosis, phaeohyphomycosis and mycetoma?
"Exophiala jeanselmei and Phialophora verrucosa Depends on host."
T/F: Many molds produce melanin and a positive Fontana Masson should not be used alone to prove the diagnosis of phaeohyphomycosis.
True. Must interpret results in context of fungal morphology: phaeohyphomycotic organisms have thick refractile walls and prominent bubbly cytoplasm (vs thin delicate walls in Aspergillus, Fusarium).
Many black molds cause phaeohyphomycosis and some of these (Phialophora and E.jeanselmei) can also cause chromoblastomycosis or mycetoma. What distinguishes these 3 diseases if the same organism can cause all of them?
Morphology of the fungus in tissue. Sclerotic bodies are only seen in chromoblastomycosis, hyphal forms are indicative of phaeohyphomycosis and grains are seen in mycetoma.
How is phaeohyphomycosis acquired?
All forms except systemic phaeohyphomycosis are due to direct inoculation (like chromoblastomycosis). Systemic phaeohyphomycosis is seen in immunosuppressed patients and is ass'd with catheter sepsis, which makes sense given the clinical presentation (multiple dry black eschars and CNS infiltration + death usually)
What major organ system is commonly affected in systemic phaeohyphomycosis?
"CNS May even be seen in immunocompetent! Bipolaris spicifera is most common cause; Scedosporium is 2nd most common Poor prognosis, requires multiagent therapy + excision of infected brain parts"
A mix of round structures and brown hyphae in tissue biopsies is seen in what disease?
"Phaeohyphomycosis The round dilated structures are hyphae cut in cross section; they resemble spores; seen usually in Bipolaris infections (systemic phaeohyphomycosis)"
What is the treatment of choice for phaeohyphomycotic cysts?
Excision
What is the treatment of choice for superficial phaeohyphomycosis (t.nigra or alternariosis)?
Topical antifungals
What is the treatment of choice for invasive or disseminated phaeohyphomycosis?
"Excision + Itraconazole If CNS dz present, use combination of Amphotericin B, Flucytosine and Itraconazole + excision of brain portions!!!"
T/F: Alternaria is a plant mold that is an emerging cause of phaeohyphomycosis.
True. Mostly seen in immunosuppressed pts (s/p transplant or Cushing's syndrome). Presents with pigmented patches or ulcerated papules/plaques on face, hands, arms. Surgical excision is treatment of choice. If widespread, Itraconazole.
What is Madura foot?
"Mycetoma (either actinomycetoma or eumycetoma). Presents as progressive SQ swelling + draining sinus tracts that discharge grains"
Eumycetoma is caused by_____
Fungi. Actinomycetoma is caused by filamentous bacteria.
Where do mycetomas initially begin?
Instep or toe webs. They progress slowly to form sinuses and deeper involvement of underlying fascia and bone.
T/F: Mycetomas occurring in covered areas of skin are almost always actinomycetomas.
True. Most mycetomas occur on exposed areas, but those that occur on covered areas are always actinomycetomas.
What are the causes of actinomycetoma?
Nocardia, Actinomadura, Actinomyces
What are the causes of eumycetomas?
"Most Common = Pseudallescheria boydii (aka Scedosporium apiospermum, the asexual form) Also: Madurella, Acremonium, Phialophora verrucosa or E.jeanselmei (both may also cause phaeohyphomycosis and chromoblastomycosis), Leptosphaeria"
What is the major cause of "lumpy jaw" type of mycetoma?
Actinomyces israelii
T/F: Almost all actinomycetomas produce light colored grains.
"True! For boards, only need to remember A.pelletieri = red"
The most common cause of eumycetoma produces what color grains?
"White (Pseudallescheria Boydii) Mnemomic: Black grains are produced by the ""Ugly (Phaeo) and the Mad (Madurella)"" groups"
Which type of mycetoma is more common in the USA: Actinomycetoma or Eumycetoma?
Actinomycetoma (3:1)
What does histology of actinomycetoma show?
Stellate abscesses containing grains (Gram+ thin filaments 1-2 um thick, embedded in a Gram negative amorphous matrix)
What does histology of actinomycetoma show?
Hyphae within the grain (best seen with GMS or PAS)
A person presents with lumpy jaw and features of actinomycetoma are seen on biopsy. You wish to culture the tissue. What culture medium is required?
Brain-heart infusion agar, incubated aerobically and anaerobically at 37 C.
What is the triad for confident diagnosis of a mycetoma?
Tumefaction, sinuses, granules
T/F: Actinomycetomas usually respond to systemic antibiotics, so surgery is not always required.
"True. A.israelii: PCN Nocardia: Sulfa abx"
Is actinomycetoma or eumycetoma harder to treat?
Eumycetomas often do not respond to systemic antifungals and require amputation (makes sense since we commonly have to amputate chromoblastomycosis too, which is caused by many of same organisms)
What is a common location for lobomycosis?
Ear is commonly involved and looks like cauliflower ear. Any part of the body may be affected, however.
What demographic group is at highest risk for lobomycosis?
Agricultural laborers. M=F
You suspect a patient may have lobomycosis. How can the diagnosis be made?
"Biopsy typically shows numerous thick-walled spherules arranged in chains, resembling children's pop beads Cannot be cultured since Lacazia loboi is an obligate parasite. Would need mouse footpads to culture."
What is the treatment of choice for lobomycosis?
Surgical excision +/- itraconazole, cryotherapy or clofazamine
A Sri Lankan patient who lives near stagnant water comes into clinic for a friable, polypoid eruption involving the nasal mucosa, conjunctiva and urethra. She also has genital lesions resembling condyloma. Biopsy shows spherules 7-10um in diameter contained in large cystic sporangia measuring 300um in diameter. What is the diagnosis?
Rhinosporidiosis. Is a polypoid disease affecting all mucous membranes, sometimes resembling condyloma. Occurs in Sri Lanka, India, Asia and Latin America. The organism is found near stagnant water. Treatment of choice is excision or destructive methods.
An Indian patient who lives near stagnant water comes into clinic for a friable, polypoid eruption involving the nasal mucosa, conjunctiva and urethra. She also has genital lesions resembling condyloma. What is expected on biopsy?
Biopsy of rhinosporidiosis shows spherules 7-10um in diameter contained in large cystic sporangia measuring 300um in diameter. It may resemble coccidioidomycosis but differs in that it always has a central nucleus. Granulomatous inflammation is seen, along with occasional transepidermal elimination of sporangia.
An Indian patient who lives near stagnant water comes into clinic for a friable, polypoid eruption involving the nasal mucosa, conjunctiva and urethra. She also has genital lesions resembling condyloma. Biopsy shows spherules within large (300um) cystic sporangia, each containing a central nucleus. What is the treatment of choice?
Excision or destruction with ED&C
Why might ciprofloxacin be of value in treating Rhinosporidiosis?
Rhinosporidiosis is thought to be due to synergistic infection with Microcystis aeruginosa (a cyanobacterium that lives symbiotically with
An Indian patient who lives near stagnant water comes into clinic for a friable, polypoid eruption involving the nasal mucosa, conjunctiva and urethra. She also has genital lesions resembling condyloma. Biopsy shows spherules within large (300um) cystic sporangia, each containing a central nucleus. What is the causative agent?
Rhinosporidiosis is thought to be due to synergistic infection with Rhinosporidium Seeberi and Microcystis aeruginosa (a cyanobacterium that lives symbiotically with
What is another name for phycomycosis?
Zygomycosis
What 2 orders within the class Zygomycetes most commonly cause skin infection, and how do they differ clinically?
"* Entomophthorales: Indolent infxn occurring in healthy pts. Caused by Conidiobolus (perinasal dz) and Basidiobolus (subcutaneous dz) * Mucorales: Acute, fatal infxn; occurs in various forms of relative immunosuppression. Caused by the ubiquitous molds, Rhizopus, Absidia, Mucor, Rhizomucor, Cunninghamella, Apophysomyces, Saksenaea, Mortierella, Cokeromyces"
Rhizopus, Absidia, Mucor, Rhizomucor, Cunninghamella, Apophysomyces, Saksenaea, Mortierella, Cokeromyces are all classified under the Order (mucorales or entomophthoromycosis).
Caused by order Mucorales, which is one of two orders (the other order is entomophthoromyces) under the Class Zygomyces
The entomophthorales are an Order of the class Zygomyces that lead to more indolent, less fatal infections, and occur in healthy patients. Which organism within this class is known to cause perinasal disease?
"* Conidiobolus coronatus = perinasal disease *Babisidiobolus ranarum = subcutaneous facial lesions."
The entomophthorales are an Order of the class Zygomyces that lead to more indolent, less fatal infections, and occur in healthy patients. Which organism within this class is known to cause subcutaneous facial lesions?
"* Conidiobolus coronatus = perinasal disease *Babisidiobolus ranarum = subcutaneous facial lesions."
The entomophthorales are an Order of the class Zygomyces that lead to more indolent, less fatal infections, and occur in healthy patients. What regions of the world are most commonly affected?
"Between 15 degrees north and south of the equator. Indonesia is a hot bed"
The entomophthorales are an Order of the class Zygomyces that lead to more indolent, less fatal infections, and occur in healthy patients. What is seen on biopsy>?
Broad, aseptate hyphae branched at right angles. Splendore-Hoeppli phenomenon is common.
The entomophthorales are an Order of the class Zygomyces that lead to more indolent, less fatal infections, and occur in healthy patients. What is the treatment of choice?
SSKI. May also use azoles.
What are risk factors for Zygomycete infections of the Order mucorales (Rhizopus, Absidia, Mucor, Rhizomucor, Cunninghamella, Apophysomyces, Saksenaea, Mortierella, Cokeromyces)?
Diabetes, leukemia, lymphoma, AIDS, immunosuppressive agents, renal failure, burns
T/F: Mucocutaneous zygomycosis (order mucorales) tends to occur in immunosuppressed patients whereas primary cutaneous zygomycosis occurs in healthy people.
True. 50% of patients with primary cutaneous zygomycosis are immunocompetent
What are the 5 major clinical forms of zygomycosis (order mucorales)?
"Rhinocerebral, pulmonary, skin, GI, disseminated. All forms are vasotropic, leading to infarction, gangrene and black necrotic debris."
What fungi cause zygomycosis (Order mucorales)?
Caused by the ubiquitous molds, Rhizopus, Absidia, Mucor, Rhizomucor, Cunninghamella, Apophysomyces, Saksenaea, Mortierella, Cokeromyces. All are vasotropic and lead to necortic eschar. All have thick walled, aseptate hyphae in tissue.
An immunocompetent patient has surgery and then develops primary cutaneous zygomycosis. What is likely to be seen on biopsy?
Tissue infarction + vasotropism of fungi. Organisms are thick walled hyphae that look hollow in cross section. Right-angle branching.
What is the standard treatment for zygomycosis (Order Mucorales)?
"Excision + Liposomal Amphotericin B (more effective than conventional Ampho B) Excision alone is risky"
What antifungal agent is inactive against mucorales type of zygomycosis?
Itraconazole has been shown to be inactive against Rhizopus. This may explain why immunosuppressed patients on Itraconazole prophylaxis can still develop zygomyces.
How does Hyalohyphomycosis differ from phaeohyphomycosis?
"Caused by non-dematiaceous molds, has more delicate walls. Organisms = Penicillium, Paecilomyces, Scedosporium apiospermum (do not get confused by the fact that this is the asexual form of P.boydii, which causes chromoblastomycosis). Fusarium and Aspergillus may be tecnically included in this group since they are non-pigmented hyphae but most authors do not include them because they cause more severe disseminated dz and CNS involvement."
Fusarium and Aspergillus are non-pigmented hyphae in tissue. Although they could be considered hyalohyphomycosis, they are usually not placed under this category. Why?
Fusarium and Aspergillus cause more severe disseminated dz and CNS involvement.
Name the causative agents of hyalohyphomycosis.
"Organisms = Penicillium, Paecilomyces, Scedosporium apiospermum (do not get confused by the fact that this is the asexual form of P.boydii, which causes chromoblastomycosis). These organisms are ubiquitous, occur as saprophytes. They only cause dz in immunosuppressed pts There is no classic clinical morphology to the lesions. May be masses, ulcers, black eschars or disseminated erythema"
T/F: Hyalohyphomycosis organisms are ubiquitous saprophytes and only cause dz in immunosuppressed pts.
"True. Organisms = Penicillium, Paecilomyces, Scedosporium apiospermum (do not get confused by the fact that this is the asexual form of P.boydii, which causes chromoblastomycosis)."
What is the classic clinical morphology of hyalohyphomycosis?
There is no classic clinical morphology to the lesions. May be masses, ulcers, black eschars or disseminated erythema
Which organism within the category of hyalohyphomycosis resembles Histoplasmosis on tissue biopsy and is considered an indicator of HIV disease?
"Penicillium marneffei, especially in Southeast Asia Dimorphic fungus with small intracellular organisms on tissue biopsy resembling Histoplasmosis"
What is the treatment of choice for hyalohyphomycosis?
Excision + Amphotericin B
Fusariosis and aspergillus both commonly affect immunocompromised patients and are associated with a high mortality compared to other non-pigmented filamentous fungal infections (hyalohyphomycosis). In many ways they are hard to distinguish from eachother. Which one can be reliably diagnosed via blood culture?
Fusariosis. Aspergillus blood cultures are not reliable.
What type of patients are at risk for hyalohyphomycosis?
Patients with hematologic malignancy, neutropenia, transplant patients.
How often are skin lesions seen in Fusariosis?
70% of pts. Blood cultures usually positive (vs Aspergillus). Acquired from contaminated hospital plumbing and aerosolization of Fusarium by shower heads. High mortality rate. Treatment of choice = Amphotericin B and lamisil +/- GCSF
What are the 2 most common causes of opportunistic fungal infections in patients with leukemia or other hematologic malignancy?
"#1 Candida #2 Aspergillus"
What is the biggest risk factor for developing invasive aspergillosis?
"Neutropenia. Invasive aspergillosis usually occurs in pts with leukemia or other hematologic malignancies and is the #2 cause of opportunistic fungal infection in leukemia patients (after candida)"
How often is pulmonary involvement seen in invasive aspergillosis? How often is skin disease seen in invasive aspergillosis?
"70% have pulmonary, only 10% have skin Blood cultures are not sensitive (vs Fusariosis)"
What is the most common causative fungus in disseminated aspergillosis with skin involvement?
"A.fumigatus Grows on media without cyclohexamide In tissues, organisms are slender hyphae with delicate walls (vs phaeohyphomycosis) and bubbly cytoplasm. Appearance in tissue is identical to Fusariosis: both have 45 degree branching and are vasotropic."
T/F: Fusariosis and Aspergillus are similar in most respects, in that they both affect immunosuppressed pts with hematologic malignancies and appear identical in tissue biopsies.
True. In tissues, both organisms are slender hyphae with delicate walls (vs phaeohyphomycosis) and bubbly cytoplasm. Both have 45 degree branching and are vasotropic and are thus associated with skin necrosis.
T/F: Aspergillus flavus rarely causes fungal balls in the lungs.
True. A.flavus causes fungal sinusitis and skin lesions.
How does Aspergillus niger present?
It is a rare cause of disseminated infxn with skin lesions
A leukemia patient with neutropenia presents with black skin eschars. A skin swab shows Aspergillus. How do you distinguish colonization from true infection?
You must obtain a deep incisional biopsy
What is the most common cause of primary cutaneous aspergillosis?
"A.flavus is the main cause of this rare disease and presents as hemorrhagic bullae and necrotic ulcers. It must be treated aggressively since it can spread from the skin to the bloodstream and become disseminated. -In contrast, A.fumigatus is the most common cause of de novo disseminated disease with secondary skin lesions"
T/F: Aspergillus is a frequent contaminant in dystrophic nail cultures.
True. However, it should be remembered that Aspergillus can also be the true cause of onychomycosis. It responds to Itraconazole (vs disseminated Aspergillosis and primary cutaneous aspergillosis, which must be treated aggressively with Amphotericin B +/- Itraconazole).
What is the treatment of choice for invasive aspergillosis?
Amphotericin B +/- Itraconazole
What disease is caused by saprophytic, achloric algae?
Protothecosis. Reproduces asexually by internal septation (morulation). Two spp exist: Prototheca wickerhamii and Prototheca zopfii. Both are found in stagnant water, tree slime and soil.
How can skin lesions of prototheca present?
"* Immunosuppressed pts: Verrucous nodules, ulcers, umbilicated papules * Healthy pts: Olecranon bursitis"
Does protothecosis of the olecranon bursa arise in healthy or immunosuppressed pts?
Healthy pts. Immunosuppressed pts present with skin lesions: Verrucous nodules, ulcers, umbilicated papules
What is the special stain that can be used to help identify protothecosis?
PAS identifies the morulating cells.
What are the 2 spp of protothecosis that cause disease in humans?
"Prototheca wickerhamii and Prototheca zopfii. P. wickerhamii more commonly possesses morulae on tissue biopsy Cyclohexamide in the culture media will suppress their growth"
An immunosuppressed patient who has been wading in slimy, stagnant water develops an infection with a saprophytic, achloric (nonpigmented) algae. What is the treatment of choice?
Amphotericin B + excision if localized dz