Corticosteroid contact hypersensitivity screening in Singapore

image Topical corticosteroids have been in use since 1957. Two percent to 5% of patients attending patch test (PT) clinics have problems with corticosteroid contact hypersensitivity. Controversies abound with regard to the choice of steroids in the standard battery, the method of patch testing and reading, and the ideal concentration and vehicle. image To assess betamethasone 17-valerate (1% pet.), fluocinolone acetonide (0.25% petrolatum [pet.]), and tixocortol pivalate (1% pet.) used in the authorsʹ standard battery. image Data were analyzed for patients seen between January 1994 and December 1996 who had positive PT reactions to one or more of these steroids. image 3,603 patients had standard PTs, of which 20 had positive reactions to one or more of these steroids. There were three positive reactions to betamethasone 17-valerate, 17 to tixocortol, and none to fluocinolone. On further patch testing to the authorsʹ steroid battery, only one tixocortol-positive patient had a positive reaction to hydrocortisone (1% ethanol/dimethyl sulfoxide [DMSO]). image Corticosteroid allergy is found to be relatively uncommon in Singapore on the basis of this screening series. The frequency of negative reactions to fluocinolone acetonide is sufficiently low for this corticosteroid to be excluded from the authors standard series. The significance of positive tixocortol reactions remains unknown. From the review of other relevant literature, the authors recommend that budesonide be added to their present series. Testing betamethasone 17-valerate in 1% ethanol may yield more positive allergic reactions. Individuals with a positive allergic PT reaction to one corticosteroid should subsequently be tested to a full corticosteroid series.