SUCCESSFUL RAPID ORAL DESENSITIZATION TO SULFASALAZINE: A NOVEL 11 STEP PROTOCOL

Introduction Sulfasalazine (SSZ) is usually associated with non-immediate hypersensitivity reactions. Immediate hypersensitivity reactions from sulfasalazine have not been well described. Case Description A 58-year-old female was evaluated for SSZ hypersensitivity reaction. She had a history of inflammatory arthritis with persistent arthralgia despite oral prednisone and methotrexate. The patient had a history of recurrent infections in the setting of hypogammaglobulinemia thus treatment with biologic agents was deferred given concern for worsening hypogammaglobulinemia. SSZ was prescribed 5 years prior for inflammatory arthritis, however, the patient developed bilateral ear pruritus and cough with wheezing within 30 minutes of receiving the drug. The patient deferred skin testing to sulfasalazine. The patient underwent an open oral challenge with 125 mg of SSZ and developed bilateral ear pruritus and coughing within 20 minutes of administration; vital signs were stable without evidence of hypotension. She received antihistamines with resolution of symptoms 40 minutes thereafter. Given that no alternative disease-modifying anti-rheumatic drug was identified, the patient underwent a successful novel 11-step oral desensitization to sulfasalazine 500 mg following pre-medications (Table 1). The patient only developed mild throat pruritus during step 6 without further reactions. The patient has tolerated SSZ without further reactions till date. Discussion Immediate reactions to SSZ are rare and most previous limited number of published desensitization protocols were intended for non-immediate hypersensitivity reactions. We present a successful oral desensitization protocol to SSZ in a patient with a previous immediate hypersensitivity reaction to SSZ which was confirmed by an open oral challenge.