A new mix for screening contact allergy to corticosteroids

Background: Topical corticosteroids (CSs) have received increasing attention in the last decade also for their sensitizing potential. This, however, is still underestimated because of some problems in testing. Objective: To reduce the number of allergens routinely tested, the safety and the usefulness of a new CS mix containing hydrocortisone 21-acetate, budesonide, desoxymethasone and hydrocortisone 17-butyrate (each 1%) was investigated in two phases. Materials and methods: During phase 1 the CS mix and its components, both in ethanol and in petrolatum, were patch tested in 3.383 consecutive patients affected by eczematous dermatitis. The subjects with positive reactions to CSs at day 4 were re-evaluated at day 7; all others were invited to return for a further reading if they developed a late reaction. During phase 2, the CS mix, another with a lower concentration of budesonide (0.1%), budesonide 1% and 0.1% (all in ethanol) were assayed in 1.407 consecutive patients. Results: Positive reactions to CS mix were observed in 30 (0.89%) and 19 (1.3%) patients patch tested during the phases 1 and 2, respectively. Data processing proved that i) the mix was safe and useful to highlight an allergy to CSs, ii) the positive reactions to CS mix were not conditioned by budesonide concentration and were induced mainly by budesonide and hydrocortisone 17-butyrate, iii) the intensity of positive reactions were increased by the concentration of compound and ethanol. Conclusions: The new CS mix with 4 marker molecules in ethanol should certainly be included in a standard patch test series.