Hemolysis and acquired methemoglobinemia associated with lidocaine and benzocaine topical application: a case report

BACKGROUND: Topical anesthetics are commonly used over the counter, and one of the adverse effects of these medications is methemoglobinemia, which is a serious and life-threatening condition. CASE PRESENTATION: We describe a 25-year-old Persian male presenting with generalized weakness, dizziness, headache, and cyanosis. In addition, he had genital warts starting 3 weeks ago, which were self-treated with podophyllin, resulting in itching and pain. He used over-the-counter topical anesthetics, including benzocaine and lidocaine, to reduce the symptoms. According to the lab data, signs and symptoms of methemoglobinemia and hemolysis were diagnosed. Considering the hemolysis, ascorbic acid was used for treatment. The patient was discharged after 5 days with normal arterial blood gas and pulse oximetry and no signs and symptoms. CONCLUSION: This case highlights that self-administration of some topical anesthetics may lead to potentially fatal conditions.