Background and aims Sulfonamide related allergic drug reactions are common, and their rate is reported to be 3.0% for the general population. Sulfasalazine (SSZ), which is an inflammatory drug in the arylamine sulfonamide structure, is being used for the treatment of many rheumatic diseases. In this study, we aimed to determine the frequency of sulfasalazine-related hypersensitivity reactions in patients with rheumatic disease.

Methods A total of 136 patients (84 RA and 52 AS) were included in this study. Patients were screened for those who recently started using sulfasalazine treatment. The type of the reaction, duration of the reaction, administered medicines, and their doses were recorded in patients with detected hypersensitivity during the follow-up. The drug was stopped and anti-histaminic and/or corticosteroid treatment was administered as needed. In patients with a negative prick test, a drug provocation test (DPT) was performed after drugs were stopped and amino salicylic acid.

Results A total of 136 patients, with ages ranging from 19 to 71 (mean 41.97±12.04), were included in the study. Hypersensitivity reaction was observed in 12/136 (8.8%) of the patients. The SSZ related hypersensitivity reaction types were: urticaria in 7 patients, urticaria and angioedema in 4 patients, and pruritus in 1 patient.

Conclusions Sulfasalazine is widely used by rheumatologists in treatment of rheumatic diseases. These reactions might be ignored because, when type 1 reaction occurs, the patient has the possibility of changing to alternative treatments. Patients who have SSZ-related allergic reactions should be advised to avoid sulfanilamide antibiotics such as sulfamethoxazole.