Joint Sparing: The Key to Unlocking Early Treatment Success in Eosinophilic Fasciitis

Delayed diagnosis is recognized as a poor prognostic factor in eosinophilic fasciitis (EF). Elevated serum eosinophil counts, a minor criterion in the diagnostic standards, occur early in the disease course. However, signs such as the groove sign and orange-peel sign typically do not appear in the initial stages, posing challenges for early detection under the current diagnostic criteria. We report a case where the combination of "joint sparing" physical findings and elevated eosinophil counts facilitated early diagnosis and treatment. A 79-year-old woman presented with an acute onset of swelling in the upper and lower limbs. Physical examination revealed non-pitting edema with "joint sparing", and blood tests showed increased eosinophil counts. Contrast-enhanced MRI of the lower limbs showed post-contrast enhancement along the fascia, leading to a diagnosis of EF. The presence of non-pitting edema with "joint sparing" may be a valuable diagnostic indicator for EF. Furthermore, combining this with serum eosinophil counts can enable early diagnosis and treatment, potentially improving patient outcomes.