DefinitionEosinophilic fasciitis is a syndrome in which muscle tissue underneath the skin, called fascia, becomes swollen and thick. Rapid swelling can occur in the hands, arms, legs, and feet.The disease is similar to scleroderma.Causes, incidence, and risk factorsThe cause of eosinophilic fasciitis is unknown. People with this condition have a build up of eosinophils, a type of white blood cell, into the affected fascia and muscles. Eosinophils are associated with allergic-type reactions, but their specific function is largely unknown.The syndrome is most common in people between ages 30 and 60. In some cases, it appears to be triggered by strenuous physical activity.SymptomsBone pain or tendernessCarpal tunnel syndromeDry, shiny nails and skinInability to make a fist with one or both ha