Systemic sclerosis (SSc)/Scleroderma
Systemic sclerosis, also known as scleroderma, is a complex, multisystem, inflammatory autoimmune disease that often progressively affects the skin, blood vessels, lungs, gastrointestinal tract, kidneys, heart, and musculoskeletal tissues. Individuals with scleroderma overproduce collagen as a result of chronic inflammation. This fibrous protein makes up connective tissue including skin, resulting in symptoms that range from cosmetic problems to tissue damage to life-threatening organ dysfunction. Although SSc is relatively rare and its prevalence is difficult to determine, it is estimated to affect as many as 250 out of every million American adults. Scleroderma can affect anyone at any age, including children, but most cases are observed in individuals aged 30 to 50, with women being affected four times more often than men. The condition may be more common in certain Native Americans, European descendants, and women of African descent.
Polymyositis (PM)
Polymyositis is a relatively uncommon chronic inflammatory disease that produces muscle weakness. The condition is characterized by chronic muscle inflammation accompanied by muscle weakness and affects skeletal muscles on both sides of the body. PM can make it difficult to climb stairs, rise from a seated position, lift objects, or reach overhead. It is considered an autoimmune disease typically observed in adults between the ages of 31 and 60 and is more common in blacks than in whites, with women affected more than men. The condition is relatively rare, with an incidence of approximately 0.5-8.4 cases per million people in the United States.
Dermatomyositis (DM)
Dermatomyositis is an uncommon inflammatory disease marked by muscle weakness and a distinctive skin rash. The condition is similar to PM in that it produces inflammation of the muscles and may also affect the joints. It produces inflammation of the skin and the underlying muscle tissue, typically involving collagen degeneration, discoloration, and swelling. The skin rash appears patchy with purple or red discolorations and typically develops on the eyelids and the muscles used to extend or straighten joints. The rash can also appear in other areas of the body. DM affects adults and children alike. In adults, DM usually occurs from the late 40s to early 60s. In children, the disease most often appears between 5 and 15 years of age. DM affects more females than males. The incidence of DM is approximately 9 cases per million population in the US.
