Levamisole toxicity mimicking autoimmune disease

Area of Science:

• Rheumatology
• Toxicology
• Dermatology

Background:

• Levamisole is a common adulterant in cocaine, linked to agranulocytosis and vasculopathy.
• Diagnostic features of levamisole-induced vasculopathy, including ANCA positivity, are often overlooked.
• Misdiagnosis leads to aggressive, unnecessary treatments for presumed autoimmune conditions.

Observation:

• A case series of six patients with purpuric lesions and vasculitic changes.
• Five patients were initially misdiagnosed with autoimmune conditions.
• All patients reported recent cocaine abuse.

Findings:

• All six patients tested positive for antineutrophil cytoplasmic antibodies (ANCA).
• Four patients exhibited additional autoimmune marker abnormalities.
• The diagnosis was confirmed as levamisole-induced vasculopathy.

Implications:

• Patients with purpuric lesions and ANCA positivity should be evaluated for cocaine use.
• Levamisole can induce ANCA positivity and other autoimmune marker abnormalities.
• Accurate diagnosis allows for less aggressive treatment strategies compared to primary ANCA-associated vasculitides.