Deposition of immunoglobulin and complement in mucocutaneous lesions related to treatment with D-penicillamine

A 23-year-old man suffering from sero-negative rheumatoid arthritis developed severe penicillamine-induced mouth ulcerations and erythematous macules. Immunohistochemical staining in a biopsy specimen from the affected lingual mucosa showed substantial deposition of IgM and C3 in vessel walls below the necrotic epithelium. In the affected skin, irregular granular staining for IgG and IgM along the epidermal basement membrane zone was noted, and granular deposits of IgM were present in small vessels of dermal papillae. The mouth ulcerations healed promptly after withdrawal of the drug, whereas the macules persisted for some months. The immunohistochemical findings indicated that the drug eruptions were related to a vasculitis induced by deposition of immune complexes.