Abstract
RATIONALE: Acquired methemoglobinemia, a rare condition, occurs due to the presence of elevated methemoglobin levels in the blood, leading to tissue hypoxia. Dapsone, commonly used in dermatological conditions, can induce methemoglobinemia. This study is important as acquired methemoglobinemia, especially induced by dapsone, is a rare but life-threatening condition. The aim of this case report is to highlight its clinical presentation and the importance of prompt diagnosis and treatment. PATIENT CONCERNS: A previously healthy 16-year-old female presented with acute cyanosis, dyspnea, palpitations, and headache 1 day after initiating dapsone 200 mg for acne. On examination, she was hemodynamically stable but had central and peripheral cyanosis. Oxygen saturation was 83% despite supplemental oxygen. Cardiopulmonary and neurological examinations were unremarkable. DIAGNOSES: Laboratory tests, including complete blood count, renal function tests, liver function tests, and electrocardiography, were within normal limits. However, arterial blood gas analysis revealed a methemoglobin level of 17%, confirming dapsone-induced methemoglobinemia. INTERVENTIONS: The offending agent was discontinued, and supportive oxygen therapy was initiated. OUTCOMES: Within 6 hours, the methemoglobin level decreased to 3%, with complete resolution of symptoms. The patient was discharged home with advice to avoid dapsone in the future. LESSONS: This case focused on the importance of methemoglobinemia in a differential diagnosis for a patient with a history of drug use, including dapsone, who exhibits symptoms and cyanosis suggestive of tissue hypoxia. In such a patient, prompt care and appropriate action will have a favorable prognosis.