Desensitization for sulfasalazine skin rash

Thirteen patients with inflammatory bowel disease and a documented allergy to sulfasalazine, manifested by skin rash with or without fever, were enrolled in a sulfasalazine-desensitization protocol. Twelve patients were successfully desensitized by using two concentrations of a liquid suspension of sulfasalazine. Four of thirteen patients developed a rash during the protocol. Although one patient refused further attempts at desensitization, the remainder completed the regimen successfully, despite recurrence of the rash on two occasions in one patient. No predilection to either fast or slow acetylator phenotype was found. This simple and convenient tolerance induction regimen may be used safely to desensitize most patients with sulfasalazine allergy manifested by skin rash with or without fever, despite recurrence of the rash during tolerance induction. Patients with serious reactions to sulfasalazine, such as agranulocytosis, toxic epidermal necrolysis, or fibrosing alveolitis, are not candidates for desensitization.