5-aminosalicylate compounds (mesalazine, sulfasalazine) are widely used in therapy of inflammatory bowel diseases. Mesalazine-induced interstitial nephritis is a rare complication, however, the risk of chronic kidney disease in affected individual is high.
A 15-year-old boy with treated idiopathic proctocolitis, consequent mesalazine-induced nephritis, and favorable response to corticotherapy is presented.