Levamisole1_0314 Derm Dx
Levamisole2_0314 Derm Dx
Levamisole3_0314 Derm Dx
Levamisole4_0314 Derm Dx
A 36-year-old female presents complaining of fever and of tender purplish patches on her ears and trunk. She denies any prior medical problems, prescription medication use, or drug, tobacco or alcohol use.
A urine toxicology screen is positive for cocaine. Other significant labs include neutropenia and a positive P-ANCA. Platelet, fibrinogen and D-dimer levels are normal.
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Levamisole is a veterinary anthelmintic drug. It has a similar appearance and melting point as cocaine, and in recent years has been noted to be a common contaminant of illicit cocaine in the United States.
In July 2009, 69% of the cocaine seized by the Drug Enforcement Agency was contaminated with levamisole at an average concentration of 10%. There have been multiple reports of levamisole-induced toxicity in cocaine users.
The classic syndrome consists of neutropenia, anti-neutrophil cytoplasmic antibody (ANCA) positivity and characteristic retiform purpura. Lesions favor the face and ears but may also appear on the trunk and extremities. Purpura may lead to frank necrosis of the affected tissue.
Skin biopsy of the affected area may show small vessel vasculitis, vasculopathy or both. Patients may develop infectious complications related to immunosuppression secondary to the neutropenia.
Levamisole has a fast half-life; therefore, it is generally not possible to detect in routine drug screenings. A urine toxicology screen to detect cocaine may be more useful.
Treatment & Prognosis
Routine wound care is appropriate treatment for skin purpura/necrosis due to levamisole toxicity. In many cases the skin will heal without significant sequelae; however, there have been cases of catastrophic necrosis of the skin and underlying soft tissue that resulted in significant morbidity.
The systemic and laboratory changes associated with levamisole will normalize within months. Infections related to the neutropenia must be treated as appropriate.
Levamisole toxicity is often considered a diagnosis of exclusion. An evaluation for other causes of vasculopathy/vasculitis, neutropenia and ANCA-positivity may be warranted.
Adam Rees, MD, is a graduate of the University of California Los Angeles School of Medicine and a resident in the Department of Dermatology at Baylor College of Medicine also in Houston.
- Rietkerk W, Pereira F, Poste J. “Small vessel vasculitis associated with cocaine use.” Cutis. 2013;91(1):21-4.
- Gaertner E, Switlyk S. “Dermatologic Complications From Levamisole-Contaminated Cocaine: A Case Report and Review of the Literature.” Cutis. 2014; 93:102-106.
- Chung C, Tumeh PC, Birnbaum R et al. “Characteristic purpura of the ears, vasculitis, and neutropenia — a potential public health epidemic associated with levamisole-adulterated cocaine.” J Am Acad Dermatol. 2011;65(4):722-5.