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What is PSS?

PSS is a group of connective tissue disorders with similar symptoms. They are associated with thickened, hardened skin, fibrosis, inflammation, blood vessel degeneration and tissue damage. PSS may be localised or systemic. It may be confined to patches of skin on the trunk, face, or extremities, or may affect large areas of the body, penetrating deep into muscle, bone, and internal organs such as the heart, lungs, gastrointestinal tract, and kidneys. Symptoms may range from cosmetic concerns to tissue damage and from pain and a decreased ability to move and use the hands to life-threatening kidney or lung dysfunction.

Localised sclerosis affects the skin and, in some cases, the muscle beneath it. There are two general types: morphea and linear scleroderma.

  • Morphea is associated with firm, thickened, discoloured oval patches of skin on the chest, back, legs, arms, or face. The patches may be reddened or white with a purplish border and may appear singly or cover large areas.
  • Linear scleroderma appears as a line or band of thickened tissue. If it forms over a child's joint, it may limit joint development and mobility.

Systemic sclerosis (SS) can be categorised as either limited SS or diffuse SS.

  • Limited SS typically affects specific areas of the body and may be referred to as "CREST," an acronym for the most common symptoms (see Signs & Symptoms).
  • Progressive SS is widespread. It can affect the skin and cause dysfunction in systems and organs throughout the body.

PSS is relatively rare and its prevalence is somewhat difficult to determine. It is estimated that there are about 240 cases for every million people, with about 19 new cases per million people each year. PSS is inflammatory and appears to have an autoimmune component, but the exact cause of the related disorders is not yet known. They can affect anyone at any age but most cases are seen in those who are between 20 and 40 years old. Women of child-bearing age are affected four times more often than men, so it is suspected that the disorders also have a hormonal component. Although a predisposition is not directly inherited, there are some increased frequencies of PSS tied to ethnicity. Localised SS is more common in those of European descent, while systemic sclerosis affects more women of African descent. PSS-like disorders are seen with exposures to chemicals such as vinyl chloride, trichloroethylene, and contaminated rapeseed oil, but SS itself has not been tied to an environmental trigger.


Last Review Date: July 18, 2016