Falsa hipersensibilidad a mesalazina como causa de escalamiento terapéutico

Mesalazine is the drug of choice in patients with mild-moderate forms of ulcerative colitis, both for inducing clinical remission and for maintenance. In fact, half of patients will be controlled with mesalazine only during their progress. It is overall considered a safe drug, with few adverse effects. Still, some cases of hypersensitivity to aminosalicylates of idiosyncratic nature have been described, which could lead to the withdrawal of the drug. This could notably limit the chances of therapeutic management, especially in patients with a mild or moderate activity or in those with exclusively rectal involvement. We present 2 cases of ulcerative proctitis where an allergy to mesalazine was suspected, what led to an inadequate control of the disease. Upon completion of the immunoallergic study the sensitivity was ruled out, the drug was reintroduced and fast and prolonged clinical remission was achieved.