Treating Vasculitis Arising From Levamisole-Contaminated Cocaine
Researchers have noted an increasing incidence in both cutaneous vasculopathy and levamisole-contaminated cocaine. Accordingly, these authors describe the diagnosis and treatment of lower extremity vasculitis caused by use of the adulterated narcotic.
Levamisole is an immunomodulator that veterinarians use as an anthelmintic agent. Physicians previously used levamisole to treat nephritic syndrome, autoimmune disorders, various cancers and some skin conditions in humans, but it was pulled from the market in the United States in 1999 secondary to leukopenia, agranulocytosis and skin vasculitis.1-8 Recently, levamisole has become more prevalent in the medical literature as a widespread adulterant to street cocaine. Reports from the Centers for Disease Control and Prevention (CDC) indicate 69 percent of cocaine is contaminated with levamisole with other sources estimating even higher rates.9,10 The incidence of cutaneous vasculopathy has experienced concordant growth in emergency department encounters and in the medical literature.10
In addition to finding pathognomonic cutaneous lesions of the nose and ears in those who have come into contact with levamisole, research from Maricopa Medical Center in Phoenix has indicated that 87.5 percent of cases involve lesions in the lower extremity, which is similar to other published data.10,11 Note that more than just “coming in contact” with the levamisole is required to produce the cutaneous lesions. Therefore, with the increased incidence and the implications for the lower extremities, foot and ankle specialists taking ER calls need to know how to recognize and treat these lesions.
Current Insights On Levamisole Use In Cocaine
The emergence of this cutaneous vasculopathic condition is relatively recent despite cocaine’s use since the 1800s. Currently, cocaine use is widespread in the United States. With an estimation of 2 to 5 million users, the United States is the world’s largest consumer of cocaine.12-14 In July 1999, the Drug Enforcement Administration reported that 69 percent of all cocaine seized at U.S. borders contained levamisole and at a concentration of about 10 percent.9 There have been various hypotheses regarding the addition of levamisole to cocaine but a recent study found that its metabolite aminorex is a powerful inhibitor of dopamine and norepinephrine reuptake, increases the release of serotonin and enhances synaptic catecholamine activity, which may enhance or prolong the effects of cocaine.15 As the presence of the contaminant and the frequency of cocaine use have increased, so have the associated numbers of levamisole-related adverse effects.
Agranulocytosis is not common. There are reportedly only 7.2 cases per 1 million in population per year, excluding patients with cancer and patients receiving cytotoxic drugs. However, agranulocytosis carries a risk for opportunistic infections and can be fatal in approximately 7 to 10 percent of cases.16 Cocaine use alone does not evoke agranulocytosis, neutropenia and characteristic vasculitis, but research has shown that these conditions can result from oral levamisole in up to 13 percent of patients using levamisole clinically.17