Antihistamines in the Treatment of Atopic Dermatitis

Background: Atopic dermatitis (AD) is an inflammatory skin disorder that is exceedingly challenging to treat. A prominent feature of AD is chronic pruritus. Early evidence suggested that pruritus in AD was partially due to mast cell release of histamine. Conversely, recent studies do not validate the role of histamine in the pathogenesis of pruritus. Conventional management continues to include the wide use of antihistamines to treat the persistent itch, however, there is an urgent need for therapy which will reduce the severity of pruritus for these patients. Objective: To review the evidence in the literature for the use of antihistamines in the treatment of atopic dermatitis. Methods: A MEDLINE search (1966–2002) was performed to obtain studies examining the use of antihistamines in the treatment of atopic dermatitis. Search terms included: atopic dermatitis; eczema; antihistamines; azatadine; brompheniramine; cetirizine; chlorpheniramine; clemastine; cyclizine; cyproheptadine; desloratadine; diphenhydramine; fexofenadine; hydroxyzine; loratadine; meclizine; promethazine; trimeprazine. Further references were gathered from these publications. Results: Historically, antihistamines have been used in the treatment of AD. However, this review shows that the evidence for its use is inconclusive. At present, several antihistamines continue to provide relief of pruritus by central sedation, and they can also be used therapeutically for concomitant allergic conditions associated with AD. More clinical trials examining the therapeutic efficacy of antihistamines, especially with the newer nonsedating antihistamines, are necessary to elucidate their role in the treatment of AD. Conclusion: Dermatologists require additional evidence regarding the efficacy of antihistamines and their mechanism of action in the treatment of AD to enhance patient care.