New treatments for atopic dermatitis

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.

Development of a novel Ag-specific immunotherapy using CpG oligodeoxynucleotides in a new, unique mouse cutaneous eosinophilic inflammation model

The number of patients with severe atopic dermatitis (AD) has been on the rise recently. We are therefore urgently in need of a treatment that can suppress Th2 cell-mediated responses in an Ag-specific fashion. Oligodeoxynucleotides (ODN)containing CpG motifs (CpG ODN) have been highlighted as immunomodulators that reduce Th2-mediated responses. To determine the effect of CpG ODN on Th2-mediated skin inflammation, we first developed a reproducible murine model of protein Ag-induced eosinophilic inflammation that is accompanied by epidermal acanthosis and increased serum IgE levels as seen in AD. In this model we found that treatment with CpG ODN during epicutaneous sensitization in previously i.p.-primed mice prevented the development of Th2-mediated responses. Furthermore, to evaluate the therapeutic effect of CpG ODN on established eosinophilic inflammation, mice were treated with a course of the immunotherapy at a skin site remote from the area of Ag application prior to the second 1-wk epicutaneous exposure to Ag. Therapeutic treatment with CpG ODN plus Ag, but not that with CpG ODN alone, could reverse the established eosinophilic inflammation. The presented results provide strong evidence for the feasibility of a novel Ag-specific immunomodulator to treat cutaneous eosinophilic inflammation such as that characteristically found in patients with severe AD.

Topical tacrolimus in alopecia areata

Eleven patients with alopecia areata affecting 10% to 75% of the scalp, average duration 6 years, had no terminal hair growth in response to tacrolimus ointment 0.1% applied twice daily for 24 weeks. Treatment failure may reflect insufficient depth of penetration of the ointment formulation and less than optimal patient selection.

Therapy of alopecia areata: on the cusp and in the future

Over the past decade, basic research has established alopecia areata as a T cell-mediated autoimmune disease and has clarified many of its genetic, cellular, and molecular aspects. Perifollicular and intrafollicular mononuclear cell infiltrates directed at anagen hair bulbs are characteristic and striking histologic features in early alopecia areata. The inflammatory infiltrate is composed predominantly of activated CD4+ and CD8+ T cells, together with macrophages and Langerhans cells. The initiation phase of alopecia areata is mediated by type 1 cytokines, including interleukin-2, interferon-gamma, and tumor necrosis factor-alpha. Like other diseases with a strong autoimmune component, alopecia areata has associated with it specific human leukocyte antigens, which determine susceptibility, severity, chronicity, and resistance. New topical immunomodulating drugs and biologic therapies that have been developed, or that are in development, for the treatment of other immune-mediated inflammatory skin diseases will likely be effective in alopecia areata as well. The present discussion addresses the treatment of alopecia areata within the framework of these new modalities.

Atopic diseases of childhood

The atopic diseases of childhood consist of the triad of asthma, allergic rhinitis, and atopic dermatitis. All share a common pathogenesis, being mediated by IgE, and are frequently present together in the same individual and family. These disorders and their comorbidities comprise a large component of general pediatric practice and their incidence in developed countries has been increasing over the past few decades. They are a leading reason for clinic and emergency room visits, as well as hospital admissions. They have the potential to interfere with education, physical activity, socialization, and self-esteem. Fortunately, we now have a reasonable armamentarium of maintenance medications available to help control these disorders and improve the quality of life for children suffering from them. In addition, early diagnosis and aggressive management of these disorders seem to offer the possibility of altering their natural history. As such, developing a sensible approach to the diagnosis and treatment of these disorders in an outpatient setting is essential. In this review, I summarize the most current literature and provide a framework for effectively diagnosing and managing these disorders.