Lipid-lowering agent-triggered dermatomyositis and polymyositis: a case series and literature review.

Lipid-lowering agent-triggered dermatomyositis (DM) or polymyositis (PM) is a rare event. Therefore, the aim of the present study was to describe a series of such cases. A retrospective cohort study of 5 DM and 4 PM cases triggered by prior exposure to lipid-lowering agents between 2001 and 2017 was carried out. All patients, except for two cases, had muscle biopsy compatible with inflammatory myopathy and no serum autoantibodies positive for anti-SRP or anti-HMGCoAR. Median age of the patients at time of diagnosis was 68 years. Seven patients had previously taken simvastatin 20 mg/day (exposure period from 2 days to 4 years) and two bezafibrate 100 mg/day (3-4 months). Median time from symptom onset to disease diagnosis was 6 months. All patients with DM had a heliotrope and/or Gottron's papules. All patients had symmetrical, predominantly proximal muscle weakness of limbs, with median serum creatine phosphokinase of 3087U/L (interquartile 25-75% range 1293-13,937 U/L). All patients received glucocorticoid and immunosuppressants. Complete reversal of clinical symptoms and normalization of serum creatine phosphokinase level occurred within a median of 12 months after starting the treatment. There was disease relapse in three cases, and one case of death was unrelated to the disease (pulmonary infectious complications resulting from lymphoma). In contrast to cases described in the literature, the patients in the present study had a relatively more aggressive course, requiring glucocorticoids and immunosuppressants, in addition to a tendency for a longer period to achieve disease remission.