Antihistamines in the treatment of urticarial disorders.

A number of studies of the effects of antihistamines on chronic idiopathic urticaria and itch are reviewed. In chronic idiopathic urticaria, terfenadine has been shown to control the number, size, and duration of skin whealing as well as itch. Likewise, in chronic dermatographic urticaria, the minimal force required to produce whealing is increased, while severity of itch is decreased following treatment with terfenadine. In both conditions, however, wheal formation is not completely inhibited, suggesting the involvement of a mechanism unrelated to histamine. In nonurticarial disease in which histamine is not involved in the pathogenesis, antihistamines appear to work as antipruritics, but by a sedative-related property and not by antagonism of H1-receptors.