BACKGROUND: Treatment with sulphasalazine of patients with mild and moderate 
forms of Crohn's disease may result in side effects in some of them.
CASE REPORT: An 11-year-old girl with Crohn's disease was given 40 mg/kd/day of 
sulphasalazine after achieving remission with prednisone. She developed 
urticaria and eosionophilia 8 days later, then extended skin edema during a 
second course of sulphasalazine requiring methyl prednisolone therapy. 
Mesalazine administration (25 mg/kg/day), one month later, resulted to watery 
stools, vomiting, and fever, a side effect observed again after two further 
mesalazine challenges of one-month interval. Eosionophilia was present and the 
lymphocyte stimulation test with mesalazine was positive. Successful 
desensitization to sulphasalazine could be obtained 9 months later permitting 
further safe administration of this drug up to 18 months.
CONCLUSION: Hypersensitivity to sulphasalazine may be successfully overcame by 
oral desensitization, especially in those patients with low-grade activity of 
Crohn's disease.