BACKGROUND: Contact hypersensitivity to corticosteroids is increasingly reported and has been identified as a problem of considerable clinical relevance. The prevalence of positive patch tests to corticosteroids ranges from 0.2 up to 5%. OBJECTIVE: The prevalence of positive patch tests to corticosteroids in Switzerland was determined in a multi-centre study of patients undergoing routine patch tests. METHODS: As representatives of corticosteroid groups, the following substances were used for screening: tixocortol pivalate and hydrocortisone for group A (hydrocortisone type), hydrocortisone butyrate for group D (hydrocortisone butyrate type) and budesonide for both groups B (triamcinolone type) and D. Patients positive for at least one corticosteroid were retested with the screening series and 12 corticosteroids commonly used in Switzerland. RESULTS: Among 3,016 consecutive patients, 65 individuals (2.2%) with a total of 106 positive reactions were found. Retesting showed a concordance of 70-98%, depending on the corticosteroid and the score of the positive reaction. In the subsequently tested corticosteroid series including 12 substances, 19 out of 56 screening-positive patients had a positive result to one or several corticosteroids. There were only few evident cross-reactive patterns in between the corticosteroids tested. CONCLUSIONS: Corticosteroids should be included in routine patch testing, because contact sensitization to a corticosteroid is of considerable practical importance. We confirm that as markers of corticosteroid sensitization tixocortol pivalate, budesonide and hydrocortisone butyrate may be suited, because there is no single corticosteroid which is a marker for all four corticosteroid groups. Patch test reactions of 2+ or higher have a better reproducibility than 1+ reactions.