Eosinophilic Fasciitis Workup

Updated: Oct 10, 2022
  • Author: Peter M Henning, DO; Chief Editor: Herbert S Diamond, MD  more...
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Laboratory Studies

Characteristic laboratory findings of eosinophilic fasciitis (EF) include the following:

  • Peripheral blood eosinophilia is present in 61%-83% of patients. The degree of eosinophilia is variable over time, even in the absence of specific therapy. [14, 45, 46]
  • Hypergammaglobulinemia is characteristic, although this finding varies widely by case series, occurring in 18%-67% of patients. It is most often due to a polyclonal increase in immunoglobulin G. [34, 15, 45]
  • An increase in the erythrocyte sedimentation rate (ESR) is found in 29%-70% of cases. [34]

Additional laboratory findings of eosinophilic fasciitis include the following: [14, 15, 45]

  • Serum creatine kinase and aldolase levels are generally normal.
  • Rheumatoid factor (RF) and antinuclear antibodies are occasionally positive.
  • Hematologic abnormalities and disease are associated with eosinophilic fasciitis. Aplastic anemia, although rare, is the most frequent common associated hematological complication, but cases have been described with thrombocytopenia, hemolytic anemia, pernicious anemia, lymphoma, and leukemia. [35, 47]
  • Borrelia serology or polymerase chain reaction (PCR) findings are occasionally positive and may suggest a treatable etiology. However, as discussed above, the exact correlation between eosinophilic fasciitis and Borrelia remains unclear. [20, 21]
  • Metalloproteinase 1 (TIMP-1) may be a new serologic marker of disease activity. [13]

Imaging Studies

Magnetic resonance imaging (MRI) is the imaging modality of choice. MRI of the involved areas shows characteristic findings of fascial thickening, abnormal signal intensity, and contrast enhancement. Additionally, MRI aids in making the diagnosis, locating the biopsy site, and monitoring the response to treatment. [48, 49, 50, 51]

Although it has not been used frequently or studied extensively in eosinophilic fasciitis, one case report has shown that ultrasonography can aid in early diagnosis. [52] According to a study by Kissin et al that included 12 patients with eosinophilic fasciitis, a 12-MHz, B-mode ultrasound may be used to measure subcutaneous compressibility and thereby serve as an adjunctive tool to distinguish eosinophilic fasciitis from diffuse systemic sclerosis, especially when tissue sampling is less feasible or when the result of tissue sampling is equivocal. [53]

Au Eong and colleagues reported a case of eosinophilic fasciitis with ultrasonography findings of increased muscle fascial thickness, lack of compressibility of the muscular fascia, and a hyperechoic tram-track appearance of the borders of the superficial and deep layers of muscular fascia. After three weeks of treatment, a follow-up ultrasound showed a reduction in superficial and deep fascial thickness and a single linear fascia. [54]



Other Tests

While eosinophilic fasciitis is generally not associated with myositis or myopathy, electromyography has occasionally been performed, and findings may be abnormal in the presence of normal serum muscle enzymes. [15]

Pulmonary function testing may show a restrictive pattern in patients with severe truncal involvement. [15]



Definitive diagnosis relies on a full-thickness incisional skin biopsy. The specimen should include the skin, fat, fascia, and superficial muscle in continuity. Biopsy is especially important in an atypical presentation. [55, 56, 57]


Histologic Findings

Inflammation, edema, thickening, and sclerosis of the fascia are hallmarks of eosinophilic fasciitis. Acute findings include infiltration of deep fascia and an adjacent subcutis layer with lymphocytes, plasma cells, histiocytes, and eosinophils. Distribution of the eosinophils in the fascia may be focal, and a close relationship appears to exist between blood and tissue eosinophilia. In the deeper portions of the panniculus, a similar infiltrate is found in the fibrous septa and at the periphery of the fat lobules. Deep in the fascia, the inflammatory infiltrate can extend into the epimysium, perimysium, and endomysium. In addition, vascular cuffing with lymphocytes and plasma cells is often seen. [11, 30, 58]

As the disease progresses, inflammatory changes are replaced by generalized sclerosis and thickening of the fascia and adjacent tissue layers. The sclerosis can be dense with hyalinized collagen bands running parallel to the fascia and small foci of fat cells trapped between them. [45, 59] See the image below.

Eosinophilic fasciitis. Top: In this gross specime Eosinophilic fasciitis. Top: In this gross specimen, the dermis (A), subcutaneous adipose tissue (B), and skeletal muscle do not appear unusual. However, the fascia (D) is markedly thickened. Bottom left: The gross findings are recapitulated in this low-power photomicrograph. The epidermis, dermis (A), and subcutaneous adipose tissue are not remarkable in this case. The fascia (D) is markedly thickened and focally infiltrated by inflammatory cells (E). The small amount of skeletal muscle (C) appears normal (hematoxylin and eosin stain at low power). Bottom right: A close-up photograph of a portion of the fascia showing mostly edematous cellular connective tissue (F). It is focally infiltrated by inflammatory cells, including lymphocytes, plasma cells, and histiocytes. The more intensely stained hypocellular pink bands across the top of the field (G) are part of an interstitial exudate of fibrin (hematoxylin and eosin stain at medium power).