Levamisole-Adulterated Cocaine-Induced Mucous Membrane Pemphigoid: Case Reports and Literature Review.

Purpose: The aim of this study was to report 2 cases of levamisole-adulterated cocaine-induced mucous membrane pemphigoid.

Methods: This study is a review of case reports and literature.

Results: Two patients presented with bilateral severe purulent conjunctivitis, corneal ulceration, and rapidly progressive forniceal shortening. Both patients were active cocaine users. A complete blood analysis showed a positive antineutrophil cytoplasmic antibody immunofluorescence with a mixed perinuclear antineutrophil cytoplasmic antibody and cytoplasmic-staining antineutrophil cytoplasmic antibody pattern. Direct immunofluorescence examination of conjunctival tissue showed linear deposition of component 3 and immunoglobulins at the basal membrane. A diagnosis of levamisole-adulterated cocaine-induced mucous membrane pemphigoid was made. In case 1, this suspicion was confirmed by investigating remnants of cocaine on the patient's debit card using mass spectrometry, which contained traces of levamisole. In both cases, aggressive immunosuppressive therapy combining systemic corticosteroids and rituximab was able to control the disease. However, by the time these therapies were initiated, significant corneal injury had occurred requiring corneal grafts in both patients.

Conclusions: Given the rising abuse of cocaine, it is important that ophthalmologists are made aware of its association with severe atypical cicatricial conjunctivitis. To the best of our knowledge, we present the first case proving the causal relationship between levamisole and ocular cicatricial pemphigoid.