Urticaria

A 4-year-old girl is brought to the emergency department with a pruritic rash of 24 hours' duration. Her mother reports that the lesions developed after the child ate strawberries.

Dr Sunita Puri of Decatur, Ala, comments that the intensely pruritic wheals of various shapes and sizes are typical of urticaria, a systemic disease with cutaneous manifestations. The condition may be caused by drug or food allergy, insect bite, or viral infection.

Wheals as large as 20 cm with central clearing can erupt with associated erythema and edema. The rash may come and go; it can appear at one location for several hours, resolve, and erupt at a distant site. Individual lesions may coalesce.

Various immunologic mechanisms for urticaria have been postulated, such as IgE antibody, complement activation, or abnormal sensitivity to vasoactive amines. Acute urticaria can resolve in less than 6 weeks; chronic disease persists.

This patient's parents were advised not to let the child eat strawberries. The youngster was given antihistamines, and her condition improved. Hydroxyzine and cyproheptadine are therapeutic options; combination H₁ and H₂ histamine blockers may be helpful in resistent cases. A glucocorticoid can be given for severe reaction. Topical corticosteroids are not useful.