The patient was given a diagnosis of levamisole toxicity, based on his clinical presentation and the fact that he had used cocaine around the time his ear lesions appeared. Levamisole—primarily a veterinary anthelmintic medication—is used on rare occasions to treat nephrotic syndrome in children. Levamisole's physical similarity to cocaine also allows it to act as a cutting or bulking agent, increasing the total weight of the sample and making the drug appear purer. Levamisole adulteration often occurs as part of the refining process of cocaine production.
Patients with levamisole toxicity present with sudden onset tender plaques or bullae with necrotic centers within days of cocaine use. Lesions primarily appear on the ears and cheeks, although they can appear almost anywhere on the body. It’s important to have a high index of suspicion for levamisole toxicity in patients using cocaine who present with unexplained neutropenia or vasculitis. If needed, tissue biopsy and urine detection of levamisole can be used to confirm the diagnosis.
Skin lesions have been reported to improve several weeks after discontinuing use of the contaminated cocaine. Known users should be referred to drug treatment centers and counseled on the risks of use.
When this patient came into the ED, he also complained of left thigh pain and swelling. A computed tomography scan revealed a deep sartorius abscess. The patient was admitted for ultrasound-guided aspiration of the abscess and IV antibiotics. His bilateral painful ear nodules persisted throughout his hospitalization, although his neutropenia resolved after 3 days.
Adapted from: Winter K, Ritter R, Viera AJ. Painful ear nodules. J Fam Pract. 2013;62:503-505.