[Toxicoderma caused by prednisone and prednisolone. Value of skin tests in the screening of cross sensitivity]

Allergic reactions to general corticosteroid therapy are uncommon.

We report a patient with systemic lupus erythematousus who developed skin rash after initiation of prednisone then prednisolone therapy. Histology evidence suggested leukocytoclastic vasculitis. The skin tests (prick tests, intradermoreactions and patch-tests) using a battery of injectable corticosteroids showed a highly positive reaction to prednisolone, methylprednisolone and dexamethasone on the intradermo-reactions 24 hours later. Histology examination of a positive-response showed leukocytoclastic vasculitis associated with eczematiform alterations of the epidermis compatible with a drug reaction. The skin tests however were negative for betamethasone, triamcinolone, paramethasone and hydrocorticose. The patient was treated with betamethasone and no skin reaction was observed.

Skin tests, particularly intradermo-reactions read 24 hours later would appear to be useful in identifying possible cross-sensitivity.