Side effects of minocycline treatment in patients with fragile X syndrome and exploration of outcome measures.
OBJECTIVE To report our experience with minocycline-induced autoimmunity (MIA) in children, with an emphasis on the potential for chronicity. STUDY DESIGN Retrospective cohort study of patients with development of rheumatologic symptoms while receiving minocycline between 1996 and 2006. RESULTS Twenty-seven children were diagnosed with MIA at a single pediatric rheumatology practice. The mean age at onset was 16.5 +/- 1.39 years. The mean duration of minocycline use before diagnosis was 13.0 +/- 10.8 months. All patients presented with constitutional symptoms. Twenty-two had polyarthralgia, and 17 had polyarthritis, mostly affecting hands and feet. On the basis of disease duration after discontinuation of minocycline, we divided subjects into 3 categories: transient, intermediate, and chronic. Seven patients had development of chronic autoimmune disease that was still active at last follow-up, a mean of 31.6 +/- 13.0 (13-48) months after onset. Six patients followed an intermediate course, with resolution of symptoms within 12 months, and 14 patients had symptoms that resolved rapidly on discontinuation of minocycline. All patients with a chronic course had evidence of arthritis at presentation. CONCLUSION A substantial proportion of children with MIA had development of chronic symptoms with the potential for significant morbidity. Physicians who prescribe minocycline should be aware of its propensity for inducing potentially serious autoimmune phenomena.