Prednisone 1mg/kg/day (up to 80mg/day)
Taper after 6-8 weeks
Taper after 6-8 weeks
Interstitial fibrosis or weakness of respiratory muscles
Methylprednisolone 1000mg/day x 3 days
Methotrexate or azathioprine for cases refractory to steroids
Methylprednisolone 1000mg/day x 3 days
Sunscreen!
Hydroxychloroquine
Other immunosuppressive meds (e.g. methotrexate, rituximab, azathioprine)
Calcium channel blockers for calcinosis
Dermatomyositis
Infection:
Polymyositis
Viral infection 
Pyomyositis
Bacterial infection
Lambert-Eaton myasthenic syndrome
Spirochete infection 