Effects of H1-antihistamine drug regimen on histamine release by nonlesional skin mast cells of patients with chronic urticaria.

Profiles of compound 48/80-induced histamine release (HR) from mast cells of uninvolved skin from patients with chronic urticaria (CU) and from a normal control (NC) group were compared, and the effects of anti-H1 medications were assessed versus placebo. Then, patients with CU (15) and NC subjects (10) were randomly assigned to take either hydroxyzine (100 mg/day), terfenadine (120 mg/day), or placebo for 28 days. The effects of such treatment on the clinical response and on the profile of compound 48/80-induced HR during a 4-hour period were analyzed. Treatment with hydroxyzine in patients with CU improved the clinical symptoms and modified the profile of HR; more histamine was recovered at 1 hour (p less than 0.05) and 2 hours (p less than 0.05), as compared with baseline. Terfenadine and placebo had no effect on the clinical response or on the profiles of HR. In the NC group, the amounts of histamine recovered at 1 hour after challenge with compound 48/80 were lower than amounts of the pretherapy values (p less than 0.01). It could be concluded that (1) the profile of HR in patients with CU is reproducible during a period of 28 days, (2) only hydroxyzine modifies both the clinical response and the profile of HR, and (3) anti-H1 compounds decrease the HR in the NC group.