Fexofenadine, an H1-receptor antagonist, partially but rapidly inhibits the itch of contact dermatitis induced by diphenylcyclopropenone in patients with alopecia areata

Antihistamines have been used for the treatment of not only allergic diseases such as allergic urticaria and rhinitis, but also of eczematous skin diseases because of their anti-pruritic effects. Moreover, the pruritus associated with eczematous diseases is considered to be induced, in part, by histamine. However, it is unclear whether antihistamines inhibit the itch of eczematous diseases in the absence of topical corticosteroids. In this study, we investigated the anti-pruritic effect of the antihistamine, fexofenadine, on the itch of contact dermatitis that was induced by topical application of diphenylcyclopropenone for the treatment for alopecia areata. Thirteen patients with alopecia areata, who had been treated weekly with topical immunotherapy with diphenylcyclopropenone for 3 months to 2 years, recorded the severity of their itching on a visual analog scale before and 3, 6, 12, 24, 48 and 72 h after application of diphenylcyclopropenone for 4 consecutive weeks. Seven patients took fexofenadine during the first and third weeks, and six patients took fexofenadine during the second and fourth weeks. The severity of itching reached a maximum 6-12 h after the induction of the contact dermatitis in most of the patients. However, fexofenadine partially but rapidly reduced the severity of itching for 72 h during the entire period of treatment in the absence of topical corticosteroids. Our results suggest that fexofenadine can be beneficial in the daily management of patients with itching due to eczematous disease.