polymyositisdermatomyositis

Polymyositis and dermatomyositis are rare autoimmune diseases that cause chronic muscle inflammation and weakness. Polymyositis affects muscles, while dermatomyositis affects both muscles and skin. These conditions are part of a group of diseases called inflammatory myopathies. The exact cause is unknown, but it is believed to involve a combination of genetic predisposition and environmental triggers.

Symptoms of polymyositis include gradual onset of muscle weakness, particularly in the muscles closest to the trunk, such as the shoulders, hips, and thighs. This weakness can make it difficult to perform everyday activities like climbing stairs, standing up from a chair, or lifting objects. Fatigue is also common. Dermatomyositis shares these muscle symptoms but also presents with characteristic skin rashes. These rashes can appear on the eyelids, knuckles, knees, elbows, and chest. Other skin manifestations may include a purplish rash on the face, a scaly scalp, or sores.

Diagnosis involves a combination of medical history, physical examination, blood tests to detect muscle enzymes and antibodies, electromyography (EMG) to assess muscle electrical activity, and muscle biopsy to examine tissue. There is no cure for polymyositis or dermatomyositis, but treatments aim to manage symptoms and prevent further muscle damage. These treatments often include corticosteroids to reduce inflammation, other immunosuppressive drugs, and physical therapy to maintain muscle strength and function. Early diagnosis and treatment are important for improving outcomes and quality of life.