Erythema annulare centrifuge

Specialty: Skin.

• figurative erythema
• persistent annular erythema

Why it occurs

• Delayed-type hypersensitivity reaction secondary to an active superficial fungal infection (commonly tinea pedis)
• Latent bacterial, viral (Epstein-Barr, Varicella-Zoster) or intestinal parasitic infections
• Adverse reactions to commonly used systemic drugs (salicylates, antimalarials, penicillin)
• Idiopathic or persistent annular erythema without identifiable cause
• Association with internal hematological or visceral neoplasms (paraneoplastic syndrome in very rapid progression variants such as erythema gyratum repens).

Initial workup

Physical examination that reveals the classic sign of the "internal scaly border" that follows the expansive erythematous area. Direct skin scraping with KOH to rule out tinea corporis annulare (which has scaling on the active outer edge). Punch skin biopsy to confirm characteristic perivascular lymphocytic inflammatory infiltrate in a "cuff" in the superficial and middle dermis.

Standard management

• Hydrocortisone 1% or mometasone furoate 0.1% cream — topical corticosteroid applied to the active edge to temporarily mitigate localized erythema and pruritus
• Cetirizine — oral antihistamine for the relief of associated pruritus, dose of 10 mg/day
• Antifungal treatment with oral or topical terbinafine if tinea pedis is demonstrated as the primary triggering infectious focus
• Suspension of unnecessary drugs or drugs that potentially trigger hypersensitivity reactions.