A case series of urticaria multiforme: Its association with Mycoplasma pneumoniae infection?

Urticaria multiforme is a rare clinical and morphological subtype of acute urticaria in childhood. Clinical features include acute onset of blanchable, annular, polycyclic, erythematous wheals with dusky or ecchymotic centers (target lesion-like). Pruritus in nearly all and edema on the face, hand and foot in the majority of cases are seen. Urticaria multiforme known as a cutaneous hypersensitivity reaction can often be misdiagnosed as erythema multiforme and serum-sickness-like reaction. Although the majority of cases have been related with viral or bacterial infections and drug use, the exact etiopathogenesis of the disease is yet unclear. Association of Mycoplasma pneumoniae infection and urticaria multiforme have been reported in only two cases in the literature. In this article, a total of four cases diagnosed as urticaria multiforme two of whom had clinical and serological proof of Mycoplasma pneumoniae infection has been presented, and diagnostic criteria, differential diagnosis, etiopathogenesis and treatment of urticaria multiforme have been reviewed