Oral antihistamine therapy influences plasma tryptase levels in adult atopic dermatitis

Abstract

Atopic dermatitis (AD) is an allergic skin disease that follows a clinical course of 'flare-up' and remission. Histamine and tryptase are inducers of pruritus and non-sedating second-generation antihistamines, including fexofenadine, are widely used for treatment of allergic skin disorders. We assessed the efficacy of a second-generation antihistamine in AD patients and examined its pharmacological effects on chemical mediators. The scoring atopic dermatitis (SCORAD) instrument and visual analogue scale (VAS) for pruritus were used to assess disease severity in 349 AD patients. Twenty patients with moderate AD symptoms, who had not received any treatment for 2 weeks, were randomly assigned into two groups. Ten patients underwent fexofenadine and emollient treatment (Group 1) and 10 received fexofenadine and steroid treatment (Group 2) for 1 week. SCORAD and VAS for pruritus, and blood histamine and tryptase levels were evaluated before and after treatment. SCORAD and VAS improved in both Group 1 (p=0.01 and p=0.006, respectively) and Group 2 (p<0.001 and p=0.001, respectively). The improvement in Group 1 showed a significant correlation with the diminution rate of blood tryptase levels (SCORAD: r=0.83 and p=0.013, respectively; VAS: r=0.81, p=0.015, respectively). End-point plasma tryptase levels were significantly lower than baseline levels in Group 2 (p=0.046). Histamine levels did not show any significant changes in either group. These results suggest that second-generation antihistamine therapy reduces AD pruritus, resulting in the effective clinical treatment for AD. In addition, monitoring tryptase levels during antihistamine therapy in moderate AD treatment may prove to be useful in establishing treatment effects.