Derm - Skin Signs Of Systemic Diseases

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Pruritis

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Itchy skin

Clinical evidence of pruritus includes lichen simplex chronicus, prurigo nodularis, and picker's nodules, which are reactive changes in the skin due to rubbing, scratching, and excoriating. Generalized pruritus without obvious signs of a skin disease requires a systemic work-up, especially in the elderly. Careful history taking and physical examination should exclude new drug exposure, urticaria, scabies, and xerosis. Rarely, pruritus may antedate development of lymphoma, and thus, lymph node examination is an important part of the physical exam. Proper blood tests should also be obtained. Xerosis by itself may cause significant pruritus or it may exacerbate the pruritic component of any skin disease.

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Stasis dermatitis

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Stasis dermatitis reflects pathologic changes of the skin due to venous insufficiency. The chronic inflammation leads to remodeling and fibrosis of the dermis and subcutis. The extravasated erythrocytes may leave behind significant amounts of hemosiderin. Cushion-like pitting edema near the ankle is the first stage of venous insufficiency. Patches of purpura and brown hemosiderin deposits eventually appear. Later, the skin is red, scaly, and may be weeping serous fluid. This stage may mimic cellulitis. Clues to statsis dermatitis include pruritus, edema, hemosiderin deposit, varicose veins, and symmetrical involvement. Treatment includes topical steroids and measures to minimize venous insufficiency.

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Lipodermatosclerosis

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Later stage stasis dermatitis where a firm circular cuff is formed that appears to strangle the distal calf, creating an inverted champagne bottle appearance. The skin becomes firm, indurated, and irregularly surfaced becoming "scleroderma-like".

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Acroangiodermatitis of Mali

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Late stage stasis dermatitis where the intense hemosiderin deposition may be difficult to differentiate from Kaposi's sarcoma.

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Toxic epidermal necrolysis (TEN)

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Acute widespread blistering eruption caused by a drug. Most common offenders are sulfonamides, anticonvulsants (phenytoin), ampicillin, allopurinol, and NSAIDs. The eruption is usually preceded by a morbilloform or generalized erythema, which then rapidly evolves into widespread sloughing of the skin in sheets. Nikolsky's sign (induction of blister by rubbing) can be elicited. Mucositis often involves the eyes, mouth, vagina, and anus. Complications are similar to a burn patient. Treatment includes supportive measures and highly controversial use of systemic corticosteroids. High does IV immunoglobulin is the newest available treatment. 25-50% mortality rate despite therapy.

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Dermatitis herpetiformis

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Immune-complex mediated blistering skin disease with a high association with celiac disease or gluten-sensitive enteropathy. Classically, dermatitis herpetiformis consists of very pruritic grouped vesicles symmetrically distributed on the knees, elbows, extensor forearms, buttock, and rarely on the scalp. Circulating antibodies found in patients with dermatitis herpetiformis include IgA antibodies to gliadin, reticulum, and smooth muscle endomysium. Treatment consists of dapsone (used to treat M. leprae) and avoidance of gluten.

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Porphyria cutanea tarda

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Most common of all porphyrias. Occurs in both familial and sporadic forms. Most gene carries are asymptomatic until liver function is compromised. Alcohol, estrogen, hexachlorobenzene, and iron overload are known to precipitate porphyria cutanea tarda. Symptoms caused by photoexcited porphyrins in the skin, which mediate oxidative damage, causing cutaneous photosensitivity reactions. The sun-exposed skin becomes very fragile, becoming easily injured by mechanical forces. Diseases observed in association with porphyria cutanea tarda include viral hepatitis (C especially), HIV, beta-thalassemia, and hemochromatosis. Treatments include phlebotomy to decrease the iron overload and antimalarials.

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Erythema nodosum

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A type of adipose inflammation. Acute, usually tender, erythematous, nodular eruption that is usually limited to the pretibial region. Arthralgia of the ankles, knees, and wrists accompany in more than 50% of the patients, which may begin prior to or during the eruptive phase. It is presumed to be a hypersensitivity reaction, which occurs in association with a variety of systemic diseases (respiratory streptococcal infection) or drug therapies (OC, sulfomamides, and penicillins). Other causes include fungal, viral, bacterial, sarcoidosis, and inflammatory bowel disease. Idiopathic cases have a worse prognosis. Treatment includes bed rest, NSAIDs, and oral corticosteroids.

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Necrobiosis lipoidica diabeticorum

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Presents as plaques with violaceous to brown border and atrophic center on the shin. Histopathologically, there are histocytes, lymphocytes, and plasma cells, which tend to be centered around blood vessels involving the dermis and the fat. There is a strong association between necrobiosis lipoidica diabeticorum and diabetes mellitus. Treatment options include potent topical steroid, intralesional steroid, ticlopidine, pentoxifylline, and asprin, but the efficacy of these drugs are limited.

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Leukocytoclastic vasculitis

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A type III hypersensitivity reaction in which immune-complex deposition on the walls of postcapillary venules results in a destructive inflammatory venulitis. Purpuric and urticarial papules are the most common presentation of leukocytoclastic vasculitis, while nodules, pustules, vesicles/bullae, and ulcers are less commonly encountered. The causes include medications, connective tissue diseases, viral or bacterial infections, and malignancies (particularly leukemias and lymphomas). Treatment includes elimination of the causative agent, NSAIDs, antihistamines, colchicine, dapsone, and systemic corticosteroids.

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Henoch-Shonlein purpura

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Specific form of leukocytoclastic vasculitis, usually a viral or bacterial-induced, frequently involving the joint, gastrointestinal tract, and kidneys. It usually occurs in children 3 to 10 years of age, although more cases are being described in adults. The immune complex consists of IgA. End stage renal failure is a particular concern in these patients.

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Polyarteritis nodosa

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Necrotizing neutrophilic vasculitis of small to medium sized arteries with a predilection for the GI tract, liver, kidneys, and skin. End organ consequences of this arteritis include bowel infarction hepatic infarction, renovascular HTN, renal infarction, and mononeuritis multiplex. When involved, the skin may manifest as livedo reticularis, plaques, nodules, or ulcerations. Microscopically, there is infiltration of neutrophils within the walls of the vessels, resulting in thomboses and eventual obliteration.

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Polyarteritis nodosa treatment

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Systemic corticosteroids and immunosuppressants. Despite aggressive therapy, mortality ranges from 20-30%.

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Antiphospholipid syndrome

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Characterized by repeated episodes of thombosis and repeated miscarriages. Autoantibodies directed against phospholipids are responsible for the hypercoagulable state. Thrombosis within arteries and veins results in livedo reticularis, painful subcutaneous nodules, and ulcerations. When associated diseases are present, they are usually autoimmune in nature (systemic lupus erythematosus). Anticoagulants are the mainstay of therapy.

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Pyoderma gangrenosum

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Essentially a diagnosis of exclusion. It may occur at any site, but usually is it on the lower extremities. Beings as a pustule or erythematous nodule, but when fully developed, the ulcer has a purulent base with an irregular undermined and overhanging gunmetal-colored border that continues to expand. 50% of the cases have an associated systemic disease, such as IBD (UC more so than Crohn's), polyarthritis, hematologic diseases such as leukemia, and IgA monoclonal gammopathy.

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Pyoderma gangrenosum treatment

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Systemic corticosteroid, cyclosporin, cyclophosphamide, dapsone, and thalidomide all have been used with variable success.

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Systemic amyloidosis

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Primary systemic amyloidosis is usually associated with an underlying plasma cell dyscrasia, including Waldenstrom's macroglobulinemia and multiple myeloma. The fibrils are composed of AL protein, which consists of immunoglobulin light chains. On the skin, the fragility of the vessels due to deposits of amyloid in the vessel walls results in petechiae, purpura, and ecchymoses, especially on the eyelids (raccoon eye sign), neck, axillae, and anogenital regions. Accumulation of amyloid in the dermis presents as papules and nodules with a slight translucent pink hue. The presence of macroglossia together with carpal tunnel syndrome is a classic presentation, which should trigger an investigation for amyloidosis.

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Eruptive xanthoma

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Appear as erythematous to yellow small papules approximately 1 to 4 mm in diameter, usually distributed over extensor surfaces of the extremities, buttocks, and hands. Triglyceride levels in these patients are very high, often exceeding 3000 to 4000 mg/dL.

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Cutaneous T-cell lymphoma - mycosis fungoides

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In the initial stage, the lesion consists of itchy scaly patches, resembling atopic dermatitis or eczema clinically and histopathologically. After many months to years, the disease may progress to plaques, nodules, and tumors. A leukemic phase may then eventuate at which time the patients become erythrodermic and Sezary cells are found in the blood.

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Kaposi's sarcoma

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All 4 variants are virally induced by human herpesvirus 8. These variants include chronic or classic type, African endemic including a fulminant lymphadenopathic type, iatrogenically immunocompromised patient type, and AIDS related epidemic type.

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Muir-Torre syndrome

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Paraneoplastic syndrome

Autosomal dominant disorder that consists of the presence of benign or malignant sebaceous neoplasms, keratoacanthomas, and adenocarcinoma of the colon. This syndrome is part of the HNPCC (MSH2 mutation). The diagnosis is based on the presence of at least one sebaceous neoplasm and a visceral malignancy in the absence of any known predisposing factor.

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What are the 3 tests for Muir-Torre syndrome?

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Gene sequencing, microsatellite instability, and immunohistochemistry

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Sweet's syndrome

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Paraneoplastic syndrome

Painful red edematous papules and plaques on the head, neck, and extremities accompanied by fever and peripheral neutrophilia. If occuring in the elderly, a work-up should exclude malignancy, particularly AML. Granulocyte stimulating factor is implicated in causing this syndrome. Oral corticosteroids and dapsone are highly effective treatments.

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Acanthosis nigricans

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Paraneoplastic syndrome

Velvety hyperpigmentation on creases of the neck and intertriginous areas of the skin characterizes acanthosis nigricans. This skin disorder is most commonly associated with obesity. Rarely, it is associated with adenocarcinoma of the GI tract.