Single doses of local betamethasone do not suppress allergic patch test reactions to nickel sulfate.

Topical corticosteroids are usually banned on test areas prior to patch testing. The previous literature on the effect of topical corticosteroids is conflicting. Patients allergic to nickel sulfate were patch tested on 4 sites with nickel on day (D) 0. Intracutaneous betamethasone was injected to test sites on D-1, D0 and D1. NaCl injection on D-1 was control. The patch test reactions were evaluated clinically and with laser Doppler. There were no differences in patch test reaction intensities on sites treated with intracutaneous betamethasone as compared to control. A single local dose of potent corticosteroid does not suppress allergic patch reactions to nickel. The current practice of avoiding topical corticosteroid use prior to patch testing should be re-evaluated.