Scleroderma is a disease of the body’s connective tissue. Connective tissue is found throughout the body, providing support and form for organs and structures. Scleroderma is thought to be an autoimmune disorder, a condition in which the immune system mistakes the body’s own tissue for a foreign invader, attacking and damaging it. Researchers believe that the immune system’s interaction with the connective tissue causes an overproduction of collagen, a tough, hard protein that makes up tendons, bones, ligaments, and scar tissue. When this collagen is deposited in various places throughout the body, it causes hardening and stiffening.

The most common areas of the body affected by scleroderma are the skin, blood vessels, joints, and internal organs, such as the heart, lungs, kidneys, and digestive system.

Layers of the Skin

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Scleroderma is classified as:

This primarily affects the skin. Localized scleroderma is further divided into:

  • Morphea—Skin lesions are firm, at times oval, whitish or brownish plaques, surrounded by a purplish ring. Different types include:
    • Plaque morphea—superficial lesions usually confined to the dermis
    • Generalized morphea—individual plaques multiply or merge and are present in 2 or more sites
    • Bullous morphea—lesions form blisters
  • Linear
    • Skin lesions appear as hardened streaks or lines along the arms, legs, or forehead.
    • May also involve subcutaneous tissue, muscle, and bone.

Usually involves Raynaud’s phenomenon, skin thickening, and involvement of lungs, gastrointestinal system, or kidneys

This is divided into:

  • Limited
    • A gradually progressing form of scleroderma that initially causes skin thickening, most commonly on the hands, forearms, feet, and lower legs
    • Usually progresses to affect the internal organs.
  • Diffuse
    • A more quickly progressing form of scleroderma that causes the skin to thicken throughout the body.
    • It may also affect the internal organs.
  • Sclerosis sine scleroderma—very rare form of scleroderma in which there are no skin manifestations, but the internal organs are affected.

Overlap syndrome occurs when a person has symptoms of 2 or more autoimmune diseases. The most common diseases include:

Involves Raynaud phenomenon and some features of systemic sclerosis.