Erythematosquamous plaque

Specialty: Skin.

• erythematous scaly plaque
• raised eczematous lesion

Why it occurs

• Atopic dermatitis in subacute or chronic phase (plaques with erythema, peeling and scratch marks due to Th2 profile inflammation)
• Psoriasis vulgaris (erythematous lesions with thick, pearly scale on spreading surfaces)
• Chronic allergic contact dermatitis (persistent inflammatory reaction to specific topical allergens)
• Tinea corporis or tinea corporis (annular erythematous plaque with central clearing and raised and scaly active edge)
• Gibert's pityriasis rosea (oval erythematous scaly plaques on the trunk following the lines of skin tension or "Christmas tree").

Initial workup

Skin scraping and direct examination with KOH to confirm the presence of septate hyphae and rule out dermatophytosis. Directed 4-mm punch skin biopsy of the edge of the plaque to differentiate by histopathology between psoriasis (regular epidermal hyperplasia, parakeratosis), eczematous dermatitis (dermal spongiosis, lymphocytic infiltrate) or cutaneous T-cell lymphoma (epidermotropism of atypical lymphocytes).

Standard management

• Mometasone furoate 0.1% cream or ointment — high-potency corticosteroid useful for acute inflammatory control, applied once a day for a maximum of 2 weeks
• Tacrolimus 0.1% ointment — topical immunomodulator indicated if the plaques are located on the face or folds to avoid steroid atrophy
• Ketoconazole 2% cream — indicated if the suspicion or confirmation is directed towards dermatophytosis or severe seborrheic dermatitis
• Neutral emollients based on glycerin and Vaseline applied abundantly to restore the skin barrier function.