Hypersensitivity to Febuxostat in a Patient with a Previous Allopurinolinduced Steven-Johnson Syndrome: A Case Report of Treatment with a Slow Desensitization Protocol

Background: We report the case of a 43-year-old Chinese male with Tophaceous gout who had been living in Italy for some years. Case Presentation: Previous treatments with allopurinol had induced Steven Johnson syndrome, dictating a switch to febuxostat 80 mg daily. After two years of treatment with febuxostat, he developed a diffuse maculopapular rash with severe itching. Rheumatologists stopped febuxostat; however, gout worsened over the following years despite treatment with kalnicitrate and colchicine. Therefore, an allergy consultation was called for. A slow desensitization protocol with febuxostat was started, with a low oral dosage scheme to be increased up to 80 mg/day. Febuxostat was prepared in a solid formulation by the consultation pharmacist as pills instead of the more frequently used liquid suspension. Conclusion: The patient is currently receiving febuxostat 80 mg, and he has shown no side effects as of now, while his gout has improved. This is the first reported example and he has shown no side effect till now, while his gout improved of a successful desensitization protocol using a solid preparation of diluted febuxostat given as pills.