Suppression of histamine- and allergen-induced skin reactions: comparison of first- and second-generation antihistamines.
BACKGROUND
Nonsedating antihistamines (nsAHs) are recommended as first-line therapeutics for the treatment of mast cell-driven disorders, including allergic rhinitis and urticaria. However, their superiority over first-generation AHs (fgAHs) has recently been called into question, mainly because of the lack of supporting head-to-head therapeutic studies.


OBJECTIVE
To compare the effects of 3 modem nsAHs with those of the fgAH hydroxyzine on histamine- and allergen-induced skin reactions in a controlled, double-blind, clinical trial.


METHODS
Skin prick tests with histamine and Dermatophagoides pteronyssinus extract were performed before and 4 hours after treatment with hydroxyzine, 25 mg; desloratadine, 5 mg; epinastine, 20 mg; fexofenadine, 120 mg; or placebo. Wheal and erythema development was evaluated by digital photography and planimetric analyses.


RESULTS
The nsAHs prevented the development of positive reactions to histamine in only 10% to 20% of all individuals tested (n = 75). In contrast, more than 50% of all hydroxyzine-treated individuals showed negative test reactions to histamine (ie, wheals <7 mm2 in area or <3 mm in diameter). Similar differences, although less pronounced, were detected when comparing the effects of nsAHs with hydroxyzine on D pteronyssinus prick testing in a limited number of D pteronyssinus-sensitized individuals.


CONCLUSIONS
These results indicate that hydroxyzine is more effective than nsAHs when given as recommended in suppressing histamine-induced or allergic skin reactions. Our results suggest that higher doses of nsAHs than those currently recommended are required for the treatment of skin responses to obtain antihistaminic and antiallergic effects that are equivalent to those of fgAHs.
dos Santos
Rosaly Vieira
RV
Department of Dermatology and Allergy, Charité-Universitätsmedizin Berlin, Berlin, Germany. rosaly.vieira-dos-santos@charite.de
Magerl
Markus
M
Mlynek
Agnieszka
A
Lima
Hermenio C
HC
D000328:Adult; D000485:Allergens; D000818:Animals; D040002:Dermatophagoides pteronyssinus / Q000276:immunology; D003984:Dibenzazepines / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006632:Histamine; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D039563:Histamine H1 Antagonists, Non-Sedating / Q000627:therapeutic use*; D006801:Humans; D006919:Hydroxyzine / Q000008:administration & dosage*; D007093:Imidazoles / Q000008:administration & dosage*; D017336:Loratadine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D012221:Rhinitis, Allergic, Perennial / Q000188:drug therapy*; D012882:Skin Tests; D016593:Terfenadine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D016896:Treatment Outcome; D014581:Urticaria / Q000188:drug therapy*
D000485:Allergens; D003984:Dibenzazepines; D006634:Histamine H1 Antagonists; D039563:Histamine H1 Antagonists, Non-Sedating; D007093:Imidazoles; D006919:Hydroxyzine; D017336:Loratadine; D016593:Terfenadine; D006632:Histamine; C093230:fexofenadine; C121345:desloratadine; C053090:epinastine