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22 Cards in this Set
- Front
- Back
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Dermatophytes |
3 genera trichophyton, microsporum, epidermophyton asexual reproduction by fragmentation of hyphae |
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Epidemiology |
most commonly from other humans or animals arthrospores attach to shedded skin cells and have a prolonged viability in env. exposure is common but often a prexisiting local trauma is needed for infection |
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Patho |
metabolize keratin most often superficial and stays in the epidermis colonization leads to the immune response which is mediated by T cells appearance depends on the site and bug involved |
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Dx |
often misdiagnosed KOH preps used to collect scapings for hyphae and hair shafts for spores |
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Antifungals |
have sterols in cell walls polyenes (nystatin and amphotercicin B) bind the ergosterol in cell wall leading to pores and lysis azoles block the conversion of lanosterol to ergosterol allyamines/benzylamines inhibit squalene epoxidase whcih results in ergosterol depletion |
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Rx Topical |
nystatin only works on candida azoles are commone allylamines and benzylamines TERBINAFINE dont use steriod antifungal combo |
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Oral Rx |
Azoles = itraconazole has less toxicity but is more expernsive terbinafine is favorable but often requires approvale |
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Tinea captitis |
scaling of the scalp erythema and inflammation adenopathy, common in kids damage to the hair shaft aiwht hair loss, black dot = breaks flush with skin and appears gray patch breaks 1-2 mm above skin after the inflammation subsides appears frosted kerion = boggy indurated erythamteous plaque with pustules and exudate; scarring and alopecia |
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Tinea pedia |
athletes foot acute is very puritic erythematous vesciles between toes on soles and instep chronic = slowly progressive pruritic eryethamtous erosios and or scales between toes often with fissues |
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Tinea corporis |
pruritic, circular/oval, erythematous scaling patch/plaque spreads centrifugally central clearing with erythematous advancing border can be associated with other tinea/ tinea corposis gladiatorum |
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Tinea cruris |
corporis of the inguinal fold may spread externsively when caused by trichophyon rubrum scrotum sparred |
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Onychomycosis |
tinea unguium - toes or fingers affected = older ages, swimming, have tinea pedis or diabetes often starts at corner of great toe and spreads laterally toward cuticle nail bed is involved usually is caused by dermatophytes primarily cosmetic, sometimes pain witha ctivity, need proper diagnosis becasue often requires longterm Rx |
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Candidal intertrigo |
erythematous macerated plaques/erosions with peripheral scaling and satellite papules/pustules increased risk with obesity, DM, steroids, Abx gluteal, inguinal, interdigital, inframammary topical nystatin |
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Malassezia |
common commenal skin fungus dimorphic and lipid dependent 3 classes = tinea pityriasis versicolor, invasive infections in neutropenic hosts, and sebborheic dematitis |
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Pityriasis versicolor |
m. globosa, m. furfur and others not dermatophytes upper body scaly lesions, occurs with change from yeast to mold, color can be white to yellow to golden brown broad dx topical rx for local and oral for extensinve |
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Seborrheic dermatitis |
areas with sebum lipase activity of m. furfur, m. globusa and has proinflamm byproducts ketoconaole cream is beneficial |
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Subcu infections |
sporothrichosis mycetoma = madura foot = eumycetoma and actinomycetoma chromoblastomycosis |
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Sporothrichosis |
sporothrix schenckii dimorphic environmental fungus lower temp is mold higer temp is yeast yeast are cigar shape widespread worldwide, sphagnum moss, decaying wood, outdoors vocation commonly affected |
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Dx and Rx |
papule at site of inoculaiton usually an extermity, ulcerated but no purulent, spreads with nodules and little systemic tox can become more widespread in the jts and lunds in immune comp culture is needed to dx rx prolonged course of itraconazole |
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eumycetoma |
more cases in tropics, common in soil inoculation of conidia via splinter or thorn genetic predispostion to developing infections slow subcu nodule, classic triad of tumors, sinus tract and granules can spread to bone and fascia |
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rx and dx |
Tumor sinus granule highly suggestive, use histology and IHC prolonged course of azoles may need surgery |
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Systemic fungi |
organ system or disseminated infections that sometimes have skin lesions |
