Eosiniphilic Fasciitis

[Mike Bartolatz]

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The Merck Manual of Diagnosis and Therapy
Section 5. Musculoskeletal And Connective Tissue Disorders
Chapter 50. Diffuse Connective Tissue Disease
Topics
Rheumatoid Arthritis
Sjögren's Syndrome
Behçet's Syndrome
Relapsing Polychondritis
Systemic Lupus Erythematosus
Discoid Lupus Erythematosus
Systemic Sclerosis
Eosinophilic Fasciitis
Polymyositis And Dermatomyositis
Polymyalgia Rheumatica
Vasculitis
Temporal Arteritis
Polyarteritis Nodosa
Wegener's Granulomatosis
Mixed Connective Tissue Disease

Eosinophilic Fasciitis
A scleroderma-like disorder characterized by symmetric and painful inflammation, swelling, and induration involving arms and legs but not the most acral areas involved in scleroderma.

The cause of eosinophilic fasciitis (EF) is unknown. The disorder occurs mostly in middle-aged men but may occur in women and children.

Symptoms and Signs
Strenuous physical activity in a previously sedentary person may precipitate the illness. The initial features are pain, swelling, and inflammation of the skin, followed by induration, creating a characteristic orange-peel configuration most evident over the anterior surfaces of the extremities. The face and trunk may also occasionally be involved, with changes resembling systemic sclerosis. Carpal tunnel syndrome may also occur. Raynaud's phenomenon is not a feature.

Symptoms usually appear insidiously, with gradual restriction of arm and leg movement. Fascial involvement is characteristic, but the process may also involve tendons, synovial membranes, and muscle. Contractures commonly evolve, secondary to induration and thickening of the fascia. Fatigue and weight loss are common. Although muscle strength is unimpaired, myalgia and arthritis may occur. Sjögren's syndrome and cardiac abnormalities have been reported and, rarely, aplastic anemia and thrombocytopenia. The usual absence of Raynaud's phenomenon, telangiectasia, and significant visceral changes (eg, delayed esophageal motility) help distinguish EF from systemic sclerosis.

Diagnosis
Laboratory studies in early active disease show eosinophilia, elevated ESR, and a polyclonal IgG hypergammaglobulinemia. Serious hematologic disease, especially a lymphoproliferative process, may rarely develop. Antinuclear antibodies and rheumatoid factor are absent. There is no association with HLA class I or II antigens. Nonspecific electromyographic changes may be seen.

Diagnosis is confirmed by biopsy of affected skin and fascia deep enough to include adjacent muscle fibers. However, significant fascial inflammation may also occur in other diffuse disorders of connective tissue. The dermis may show cellular infiltration. The subdermal fascia is greatly thickened, with collagenous hyperplasia. Cellular infiltrates within the fascia, epimysium, perimysium, endomysium, and muscle include histiocytes, plasma cells, lymphocytes, and, in some cases, eosinophils. MRI can demonstrate thickened fascia, the increased signal intensity in the superficial muscle fibers correlating with the inflammation.

Prognosis and Treatment
Most patients respond rapidly to high doses of prednisone (40 to 60 mg/day followed by rapid reduction to 5 to 10 mg/day). Continued low doses may be required for 2 to 5 yr. Alternatively, hydroxychloroquine 200 to 400 mg/day may be used. Although the long-term outcome is unknown, in many patients EF is self-limited and uncomplicated.