Scleroderma overlap syndrome: Scleroderma is a connective tissue disease that causes fibrosis and vascular abnormalities, but that also has an autoimmune component.

It is described by connective tissues complications. Blood testing includes screening for the positive antinuclear antibody.

Patients have symptoms of both systemic scleroderma and/or polymyositis and dermatomyositis.

1. Scleroderma: a group of rare diseases that involve the hardening and tightening of the skin and connective tissues

and/or:

Polymyositis: a rare inflammatory disease that causes muscle weakness affecting both sides of your body

Dermatomyositis: an inflammatory disease of skin and muscle marked especially by muscular weakness and skin rash.

Scleromyositis or the PM/Scl overlap syndrome is a complex autoimmune disease (a disease in which the immune system attacks the body). Patients with scleromyositis have symptoms of both systemic scleroderma and either polymyositis or dermatomyositis, and is therefore considered an overlap syndrome. Although it is a rare disease, it is one of the more common overlap syndromes seen in scleroderma patients, together with MCTD and Antisynthetase syndrome. Autoantibodies often found in these patients are the anti-PM/Scl (anti-exosome) antibodies.

The symptoms that are seen most often are typical symptoms of the individual autoimmune diseases and include Raynaud's phenomenon, arthritis, myositis and scleroderma. Treatment of these patients is therefore strongly dependent on the exact symptoms with which a patient reports to a physician and is similar to treatment for the individual autoimmune disease, often involving either immunosuppressive or immunomodulating drugs.

- Clinical characteristics:

- Overlap Syndrome: scleroderma overlap syndrome

- Autoimmune disease

- Scleroderma myositis overlap syndrome

An overlap syndrome is an autoimmune disease of connective tissue in which a person presents with symptoms of two or more diseases.

Examples of overlap syndromes include mixed connective tissue disease and scleromyositis. Diagnosis depends on which diseases the patient shows symptoms and has positive antibodies for in their lab serology.

In overlap syndrome, features of the following diseases are found (most common listed):

- Systemic lupus erythematosus (SLE),

- Systemic sclerosis,

- Polymyositis,

- Dermatomyositis,

- Rheumatoid arthritis (RA)

- Sjögren's syndrome

- Eosinophilic granulomatosis with polyangiitis (EGPA)

- Autoimmune thyroiditis

- Antiphospholipid antibody syndrome

The treatment of overlap syndrome is mainly based on the use of corticosteroids and immunosuppressants. Biologic drugs, i.e. anti-TNFα or anti-CD20 monoclonal antibodies, have been recently introduced as alternative treatments in refractory cases. There are some concerns with the use of anti-TNF agents in patients with systemic autoimmune diseases due to the risk of triggering disease exacerbations.