Modulation of atopy patch test and skin prick test by pretreatment with 1% pimecrolimus cream.

BACKGROUND In a subgroup of patients with atopic eczema (AE), aeroallergens are relevant eliciting factors. The atopy patch test (APT) was proposed as inflammation model for AE. OBJECTIVE It was the aim of this study to investigate the effect of pretreatment with 1% pimecrolimus cream (Elidel) on the APT and skin prick test (SPT). METHODS In a randomized, controlled, double-blind study, 20 patients with AE and positive SPT and APT screening reaction to house dust mite Dermatophagoides pteronyssinus, cat dander, grass or birch pollen were enrolled (age 20 +/- 11 years, 55% males). For 2 weeks, patients twice daily applied pimecrolimus and vehicle control to marked fields on their backs and forearms. Then, APT was performed (200 index of reactivity/g extracts in petrolatum; Stallergènes, France) on both fields on the back and SPT was performed on the pretreated forearms. RESULTS Including only patients with different readings (n = 13), stronger APT suppression of at least 1 ETFAD (European Task Force on Atopic Dermatitis) grade in the pimecrolimus area versus intraindividual control was observed in 10 of these patients after 48 and 72 h (p < 0.05; 90% CI 50.5-93.4). Including all 20 subjects, the analysis still showed a borderline significance compared with the vehicle (p = 0.0564). SPT with histamine and aeroallergens showed a median 7.5-10% reduction in actively pretreated areas (p = 0.086). Immunohistochemical analysis in 2 patients revealed an induction of interferon-gamma in primecrolimus-pretreated skin. CONCLUSION APT can be used as a model for AE skin inflammation. It was shown for the first time that pimecrolimus pretreatment has a potential to suppress the development of lesions induced by aeroallergen exposure in patients with AE.