Urticaria Multiforme
A 3-year-old girl presented to the emergency department on day 1 of a mild pruritic urticarial rash. There was no history of exposure to medications or allergens and no history of similar symptoms. The parents described a viral respiratory illness that had occurred 1 week earlier. Fever (38.8°C) developed on day 2, when the child was at home, as did a generalized polycyclic annular rash with wheals and ecchymotic centers (Panel A). On day 3, the child returned to the emergency department with a persistent low-grade fever and swelling of the hands, feet, and face. Physical examination was notable for acral edema and a blanching arcuate urticarial rash (Panels B and C, respectively). Dermographism was elicited by pressure from a pen (Panel D). There was no mucosal involvement. Complete blood count, urinalysis, and serum chemical analysis were unremarkable. A diagnosis of urticaria multiforme was made, and the child was treated with diphenhydramine. The rash resolved on day 6 with no further sequelae. Because of the annular nature of the rash, a frequently antecedent infection, and its often dramatic presentation, the condition is commonly misdiagnosed as erythema multiforme or other more serious cutaneous conditions.
Makes me think of fifth disease as well. Anyhow, interesting case, thanks !
