D2.408 - Hypersensitivity Reactions to Corticosteroids: A Retrospective Cohort Study

Corticosteroids are extensively used for their anti-inflammatory and immunosuppressive properties. Although hypersensitivity reactions to corticosteroids are uncommon, they are clinically important because of the widespread use of these drugs. Such reactions are mainly classified as immediate (IgE-mediated) or non-immediate (type IV). Accurate diagnosis is crucial to avoid unnecessary drug avoidance and to identify safe alternative corticosteroids.

We retrospectively reviewed medical records of patients with suspected corticosteroid allergy evaluated at Hospital Universitario 12 de Octubre between 2014 and 2024. Demographic data, clinical characteristics, type of corticosteroid involved, route of administration, clinical presentation, and results of allergological investigations were collected. The diagnostic work-up included skin tests [(patch tests (PT), skin prick tests (SPT) and intradermal tests (ID)] and, when indicated, drug provocation tests (DPT) according to standardized protocols.

Seventy-one patients were included (mean age, 55 years; 81.7% women), of whom 21 had a history of atopy. Hypersensitivity reactions were classified as immediate in 45 patients, delayed in 25, and of unknown timing in one case. Most reactions occurred after intramuscular (46%) or oral (22%) administration. Immediate reactions included urticaria and/or angioedema (n=27), anaphylaxis (n=13), flushing (n=2), pruritus (n=1), palpitations (n=1) and one case of Kounis syndrome. Delayed reactions mainly consisted of maculopapular exanthema (n=17), followed by contact dermatitis (n=2), fixed drug eruption (n=2), erythema multiforme (n=1), acute generalized exanthematous pustulosis (AGEP) (n=1), drug reaction with eosinophilia and systemic symptoms (DRESS) (n=1) and symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) (n=1).

A complete allergological evaluation ruled out corticosteroid allergy in 20 patients. Among the 28 patients with a positive allergological work-up, PT were positive in 12 of 24 patients, mainly those with maculopapular exanthema. SPT and/or ID were positive in 8 of 69 patients, including individuals with severe reactions such as anaphylaxis. DPT were positive in eight patients. In 23 patients, the evaluation was performed directly with an alternative corticosteroid.

Our findings highlight the importance of a structured allergological evaluation, including skin tests and drug provocation tests, to confirm the diagnosis, exclude false suspicion, and identify safe alternative corticosteroids. Cross-reactivity in immediate hypersensitivity reactions is unpredictable and should therefore be evaluated on an individual basis.