Introduction: In comparison with the extremely frequent use of corticosteroids in different diseases, immediate allergic reactions remain uncommon. In addition to the steroid molecule, the causative agent of these reactions can be an excipient.

Material and methods: We report seven cases of immediate reactions induced by different preparations of corticosteroids. Skin tests with the suspected steroid and excipients were carried out. In patients with negative skin tests, oral or parenteral challenges were performed with the drug and the excipients involved. Challenge tests
with at least two other corticosteroids belonging to another or even the same group of the Coopman classification were carried out.

Results: Of the 7 patients, six had positive skin tests with the suspected preparation of corticoid: three cases with methylprednisolone acetate, two cases with carboxymethylcellulose and one case with the complete triamcinolone preparation. Only in one case did we have to challenge with the suspected steroid preparation to confirm the diagnosis. All challenge tests with other corticosteroids belonging to another or to the same group of the Coopman classification were negative.

Conclusions: The reactions were caused by the steroid molecule (Triamcinolone or methylprednisolone succinate) in four patients, by an excipient (carboxymethylcellulose) in another two patients and we could not identify the sensitized molecule in one patient. We did not demonstrate cross-reactivity between different corticosteroids.

Key words: carboxymethylcellulose, corticosteroids, hypersensitivity, methyl-prednisolone, triamcinolone.