Eosinophilic fasciitis.

Eosinophilic fasciitis is a rare scleroderma-like syndrome of unknown cause. It is characterized by painful induration and progressive thickening of the muscular fascia and subcutaneous tissue of the limbs and trunk. The most common laboratory findings include peripheral eosinophilia, hypergammaglobulinemia, and an elevated erythrocyte sedimentation rate. The diagnosis is confirmed through a full-thickness wedge biopsy of the affected skin, revealing inflammation and thickening of the deep fascia. The differential diagnosis includes scleroderma, morphea, myofasciitis in graft-versus-host disease, and epidemic fasciitis syndromes caused by toxins, such as eosinophilia-myalgia syndrome and toxic oil syndrome. Although the diagnosis is based on clinical, laboratory, and histological findings, no universal diagnostic criteria exist. Glucocorticoids are the standard treatment, although some patients may improve spontaneously.