Many conditions may cause painful edema of one or more extremities. Eosinophilic fasciitis (EF), also called Shulman syndrome, is an uncommon one, evolving into sclerodermoid cutaneous infiltration, associated with peripheral blood eosinophilia. EF is a fibrotic disease of muscle fascia and skin, whose etiology remains unclear. Several pathophysiological mechanisms have nevertheless been proposed, the major component being an imbalance between extracellular matrix production and degradation. Visceral involvement is uncommon. EF may be associated with blood disorders, which determine its prognosis. The diagnosis is confirmed by elliptical full-thickness incisional biopsy of skin and subcutaneous tissues down to the muscle surface. EF is most likely underdiagnosed due to its rarity and its similarities with other conditions, such as systemic sclerosis. The typical first-line treatment is systemic corticosteroid therapy tapered over several months. Cortico-resistant and severe-onset forms require adding another immunomodulatory agent. In this case report, we describe a typical presentation of EF, highlighting the diagnostic difficulties posed by this uncommon pathology. Based on a literature review, we also recall its underlying pathophysiological mechanisms, along with the diagnostic and therapeutic steps.
