Severe immune thrombocytopaenia in a patient taking benznidazole for chronic Chagas disease

Chagas disease is a parasitic disease that mostly affects Latin American countries, but it has currently become a worldwide epidemic due to migration. Both drugs marketed for its treatment (benznidazole and nifurtimox) are associated with a high rate of adverse reactions. Benznidazole is preferred initially because of its more favourable toxicity profile and perceived greater efficacy. Hypersensitivity dermatological reactions, gastrointestinal and neurological disturbances represent the most common drug-related adverse events. General symptoms such as fever, arthralgia, myalgia or bone marrow depression (leucopaenia) are seen less frequently. We describe the case of a 33-year-old woman with chronic Chagas disease who presented with acute gingival bleeding and severe thrombocytopaenia, probably related to benznidazole treatment. Temporal association with drug initiation and recovery after treatment withdrawal were demonstrated. Clinicians should be aware of the possible association between immune thrombocytopaenia and benznidazole, even though the pathogenesis remains unclear at present.