Objective: To describe the spectrum of clinical features in patients with minocycline-induced lupus (MIL) and determine their response to rechallenge.
Methods: The clinical features and laboratory findings of 23 patients with MIL were recorded. Ten patients were rechallenged, and their C-reactive protein (CRP) levels were monitored.
Results: All subjects complained of polyarthralgia; three had metacarpophalangeal and proximal interphalangeal joint synovitis and one had bilateral knee effusions. Elevated hepatic transaminases were noted in eight subjects. Cutaneous vasculitis was a feature in two cases. None had renal or central nervous system disease, although five patients complained of impaired concentration and poor memory and a single patient had a peripheral sensory neuropathy. The following serological abnormalities were detected: antinuclear antibodies (19/23 patients); antibodies to double-stranded DNA (4/23); perinuclear antineutrophil cytoplasmic antibodies (10/15); IgG anti-cardiolipin antibodies (6/23); hypergammaglobulinaemia (12/19). Anti-histone antibodies were negative in 9/9 cases. Rechallenge resulted in rapid recurrence of symptoms and elevation of CRP levels.
Conclusion: MIL is associated with a wide spectrum of clinical and serological features. The diagnosis can be confirmed by rechallenge, which results in rapid reappearance of symptoms and a rise in CRP.