BRONCHIAL AND CUTANEOUS RESPONSES IN ATOPIC-DERMATITIS PATIENTS AFTERALLERGEN INHALATION CHALLENGE

Background Atopic dermatitis (AD) is often associated with allergic as thma (AA). Inhalation of allergens influences the activity of AA but t he effect on the skin in AD is unclear. Objectives We evaluated the de gree of bronchial hyperresponsiveness to methacholine in eight AD pati ents with AA (AD(+)) and eight AD patients without AA (AD(-)) and stud ied bronchial and cutaneous responses after allergen inhalation challe nge. Methods All patients were treated in hospital for their eczema wi th tar ointment (pix liquida) and orally administered antihistamines ( mean hospital stay 37 days). After clearing of the skin lesions allerg en inhalation challenge was performed. Cutaneous responses were studie d by measuring the 'Costa' score before and 24 h after allergen inhala tion challenge. Results The median value of the provocative concentrat ion of methacholine causing a 20% fall (PC20 Mch) in forced expiratory volume in 1 second (FEV1) was significantly higher in the AD(-) group compared to the AD(+) group with median values of 10.70 and 0.60 mg/m L, respectively. These values did not change significantly in both gro ups during hospital stay. After challenge all AD(+) patients showed ea rly and late asthmatic responses whereas only four AD(-) patients show ed early asthmatic responses (mean values of the maximal fall in FEV1 during the EAR 37%/16% and in PEF during the LAR 27%/4% for AD(+) and AD(-) patients, respectively). The 'Costa' score increased in both gro ups (mean score before 19.1/24.4 and after challenge 26.8/26.9 for AD( +) and AD-patients, respectively). The increase in the AD(+) group was significantly higher compared with the AD(-) group (P = 0.016), Concl usion We conclude that allergen inhalation challenge causes a flare up of the skin lesions in atopic dermatitis patients. This was more prom inent in atopic dermatitis patients who already suffered from an IgE-m ediated allergic inflammation in the lung.