Eosinophilic fasciitis is a very rate syndrome in which muscle tissue under the skin, called fascia, becomes swollen and thick. The hands, arms, legs, and feet can swell quickly.

The disease may look similar to scleroderma but is not related.

The cause of eosinophilic fasciitis is unknown. In people with this condition, white blood cells called eosinophils, build up in the muscles and tissues. Eosinophils are linked to allergic reactions. The syndrome is more common in people ages 30 to 60.

• Bone pain or tenderness
• Carpal tunnel syndrome
• Muscle weakness
• Tenderness and swelling of the arms, legs and sometimes the joints
• Thickened skin that looks puckered

Tests that may be done include:

• Gamma globulins (a type of immune system cell)
• Erythrocyte sedimentation rate (ESR)
• MRI
• Muscle biopsy
• Skin biopsy

Corticosteroids and other immune-suppressing medicines are used to relieve symptoms. These medicines are more effective when started  early in the disease. Nonsteroidal anti-inflammatory drugs (NSAIDs) may also help reduce symptoms.

In most cases, the condition goes away within 3 to 5 years. However, symptoms may last longer or come back.

Arthritis is a rare complication of eosinophilic fasciitis. Some people may develop very serious blood disorders or blood-related cancers, such as aplastic anemia or leukemia. The outlook is much worse if blood diseases occur.

Call your health care provider if you have symptoms of this disorder.

There is no known prevention.

Lee LA, Werth VP. The Skin and Rhematic Diseases. In: Firestein GS, Budd RC, Gabriel SE, et al, eds. Kelley's Textbook of Rheumatology. 9th ed. Philadelphia, Pa: Saunders Elsevier;2012:chap 43.