Dermatomyositis: A Case Report and Review of a Rare Autoimmune Inflammatory Disease

Abstract

Dermatomyositis is a chronic progressive autoimmune disease of unknown etiology and rare occurrence worldwide. It is an immunologically mediated idiopathic inflammatory disease in which damage to small blood vessels contributes to injury and inflammation of muscle and skin. Dermatomyositis belongs to a heterogeneous group of three autoimmune rheumatological diseases termed idiopathic inflammatory non-suppurative myopathies, with polymyositis and inclusion body myositis as other component diseases. Dermatomyositis and polymyositis typically show characteristic clinical features of autoimmune inflammatory diseases and association with autoantibodies, HLA-DR genotype, and other autoimmune diseases. While it is known that inflammation plays a significant role in the pathogenesis of these diseases, its role in inclusion body myositis remains unclear. Overlapping forms of inflammatory myopathies that are poorly differentiated and defy a precise classification have also been identified. However, the clinical response to steroids and other immunosuppressive agents may help distinguish the subtypes of inflammatory myopathies from one another. Dermatomyositis is further described as a multisystemic rheumatologic disease presenting with muscular and cutaneous symptoms. It is associated with malignancy in 20 – 25% of patients. Dermatomyositis occurs in children and adults, with a higher incidence observed in women. Diagnosis is usually made from clinical manifestations, elevated blood enzymes, autoantibody testing, electromyography (EMG), and muscle biopsy. The diagnosis, however, remains challenging in third-world countries. There is no known cure for dermatomyositis. However, corticosteroids and other immunosuppressive agents, and intravenous immunoglobins are routinely used for treatment. The index patient in this review is a 22-year-old Afro-Caribbean woman whose presentation met the probable-to-definite criteria for diagnosis based on the Bohan and Peter Classification Criteria. This article is a case report and a detailed review of the autoimmune inflammatory disease known as dermatomyositis that can be used to teach about the disease condition.