Patch-testing with serial dilutions of tixocortol pivalate and potential cross-reactive substances

Of patch-tested patients with dermatitis, 4-5% are allergic to corticostero ids. Four groups of corticosteroids are recognized (A - D), where substance s from the same group may cross-react. We investigated the potential cross- reactivity pattern and dose-response relationship for several corticosteroi ds from group A. We also included the corresponding aldehyde to hydrocortis one, as this degradation product has been proposed to be immunogenic, Eleve n patients shown to be allergic to tixocortol pivalate were patch-tested wi th several corticosteroids from group A, as well as with the aldehyde, all in serial dilutions. All 11 reacted to both tixocortol pivalate and hydroco rtisone. The dose-response relationship for the corticosteroids tended to b e similar to sensitizers lacking anti-inflammatory potential. Patients with simultaneous reactions to many substances had high patch-test reactivity t o tixocortol pivalate and hydrocortisone, while patients with few such reac tions showed low reactivity (p=0.001 and 0.003, respectively), Several pati ents reacted to the aldehyde, supporting the theory that it is an intermedi ate in sensitization.