Free FMGE Dermatology questions

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Chronic plaque psoriasis classically produces sharply demarcated erythematous plaques with silvery scale on extensor surfaces. Scalp and sacral involvement are also common.

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Auspitz sign refers to pinpoint bleeding after removal of psoriatic scales due to exposed dilated capillaries in dermal papillae. It is supportive but not absolutely specific.

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Koebner phenomenon is the appearance of lesions of an existing dermatosis at sites of trauma. It is classically associated with psoriasis, lichen planus, and vitiligo.

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Lichen planus is remembered by its characteristic purple, polygonal, pruritic, planar papules and plaques. Wickham striae may be visible on the surface.

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Pemphigus vulgaris causes intraepidermal acantholysis, producing fragile flaccid bullae and frequent mucosal involvement. Nikolsky sign may be positive.

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Bullous pemphigoid is a subepidermal autoimmune blistering disorder that produces tense, pruritic bullae. Mucosal involvement is less common than in pemphigus vulgaris.

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Dermatitis herpetiformis is associated with celiac disease and produces intensely pruritic grouped vesicles on extensor surfaces. Granular IgA deposition is characteristic.

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Loss of sensation over a skin lesion and thickened or functionally impaired peripheral nerves are key clinical features of leprosy. Sensory testing is therefore essential.

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Tuberculoid leprosy occurs at the strong cell-mediated immunity end of the spectrum and is paucibacillary. Lesions tend to be fewer and better defined.

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Lepromatous leprosy is associated with weak cell-mediated immunity against M. leprae, numerous lesions, and a high organism burden. Nerve involvement may be more diffuse and symmetric.

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Type 2 lepra reaction, or erythema nodosum leprosum, is an immune-complex-mediated inflammatory episode in multibacillary disease. Tender nodules and systemic features are common.

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Dermatophyte infection of glabrous skin typically produces annular scaly plaques with an active border and central clearing. Potassium hydroxide preparation can demonstrate fungal hyphae.

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Topical steroids can suppress inflammation without eradicating dermatophytes, altering the appearance and allowing spread. This modified infection is termed tinea incognito.

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Scabies commonly causes intense nocturnal pruritus and household clustering. Burrows in interdigital spaces, wrists, and other characteristic sites are useful diagnostic clues.

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Atopic dermatitis is a chronic relapsing pruritic inflammatory dermatosis associated with atopy. Flexural involvement is common in older children and adults.

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Allergic contact dermatitis is a T-cell-mediated delayed hypersensitivity reaction. Nickel is a common sensitizing allergen.

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Typical urticarial wheals are transient, pruritic, edematous plaques that generally resolve within 24 hours at a given site. Persistent lesions should prompt consideration of alternatives such as urticarial vasculitis.

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Comedones result from follicular plugging and may be open or closed. Inflammatory papules, pustules, nodules, and cysts may develop subsequently.

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Vitiligo is an acquired depigmenting disorder caused by loss of functional melanocytes, often through autoimmune mechanisms. Lesions are sharply depigmented rather than merely hypopigmented.

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SJS/TEN is a severe mucocutaneous drug reaction characterized by epidermal necrosis and detachment with prominent mucosal involvement. The suspected drug should be stopped and supportive specialist care instituted urgently.