ALLOPURINOL-INDUCED SEVERE CUTANEOUS ADVERSE REACTIONS: A REPORT OF TWO CASES

Background and Objectives: Severe cutaneous adverse reactions (SCARs) are rare and frequently represent with a drug reaction. The use of allopurinol is among the drugs with the highest risk factors for SCARs worldwide. There are multiple risk factors for allopurinol-induced SCARs, including genetic and non-genetic factors. Allopurinol-induced SCARs such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome are reportedly associated with the HLA-B*58:01 genotype. Genotyping before allopurinol has not been used routinely yet; We aimed to draw attention to genotypic analysis with two cases we followed.

Material-Methods: We presented the treatment and follow-up protocol of two cases of allopurinol-induced SCARs followed in our clinic.

Results: Two patients who were treated with allopurinol for gout were diagnosed with SCARs based on clinical, laboratory and pathology results, one was diagnosed with TEN and the other was DRESS syndrome. These two cases were treated with systemic corticosteroid therapy. However, one patient died due to Covid19 pandemic infection. The patient with the diagnosis of DRESS was discharged with a corticosteroid reduction scheme and the follow-up was continued.

Conclusions: Allopurinol is the first-line agent for the treatment of gout, but it also carries the risk of serious side effects, potentially including risks of morbidity and mortality, as seen in our patient with TEN. Therefore, HLA-B genotyping can help prevent serious problems attributable to allopurinol therapy.