Purpose of review: The purpose of this paper is to comprehensively evaluate secondary causes of inflammatory myopathies (myositis) and to review treatment options. Recent findings: This review highlights recent advancements in our understanding of known causes of myositis, including newer drugs that may cause myositis such as checkpoint inhibitors and viruses such as influenza, HIV, and SARS-CoV2. We also discuss treatment for malignancy-associated myositis and overlap myositis, thought to be a separate entity from other rheumatologic diseases. Summary: Infections, drugs, rheumatologic diseases, and malignancies are important causes of myositis and are important to diagnose as they may have specific therapies beyond immunomodulatory therapy.