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Eosinophilic Fasciitis: Background, Pathophysiology, Epidemiology
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Background

Eosinophilic fasciitis (EF), also called Shulman syndrome, is a rare, localized fibrosing disorder of the fascia. The etiology and pathophysiology are unclear.

In 1974, Shulman provided an early description of eosinophilic fasciitis as a disorder characterized by peripheral eosinophilia and fasciitis that could be differentiated from scleroderma by the distinctive pattern of skin involvement that spares the digits, involves fascia rather than dermis, and is not accompanied by Raynaud phenomenon.[1, 2, 3]

Since 1974, over 300 patients with eosinophilic fasciitis have been reported.[4, 5] Despite this, the current understanding of the disease relies on a relatively few large case series and multiple case reports. Therefore, the understanding of key aspects of the disease continues to evolve.

The etiology of eosinophilic fasciitis remains unknown, although many possible triggers and disease associations have been suggested. Some aspects of pathophysiology have been elucidated; however, a more complete understanding has yet to develop.

The available literature has generated a broader clinical image of the condition, but fascial thickening in the setting of eosinophilia, elevated erythrocyte sedimentation rate, and hypergammaglobulinemia remain critical elements of the syndrome. Visceral involvement in eosinophilic fasciitis is generally absent, a finding that helps differentiate eosinophilic fasciitis from systemic sclerosis and other differential considerations. However, an association with several hematologic diseases is recognized and frequently carries a grave prognosis.

The diagnosis of eosinophilic fasciitis is suspected in a patient presenting with characteristic skin changes and consistent laboratory findings. It is confirmed with full-thickness biopsy or characteristic MRI findings. See Presentation and Workup.

Eosinophilic fasciitis is generally corticosteroid-responsive, and initial treatment regimens are based on this therapy. Multiple additional agents have been used in steroid-refractory disease. The evidence for many of these agents is anecdotal, and there is no general consensus regarding the best agent for treatment of steroid-resistant disease or cases refractory to steroid withdrawal. See Treatment and Medication.

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Pathophysiology

Although the etiology of eosinophilic fasciitis is unknown, studies have shed light on some of the mechanisms involved in its pathogenesis.

In general, the pathophysiology underlying eosinophilic fasciitis is postulated to involve an inflammatory response resulting in an activated inflammatory cell infiltrate of affected tissues and subsequent dysregulation of extracellular matrix production by lesional fibroblasts.

Viallard et al demonstrated that, when stimulated, peripheral blood mononuclear cells of eosinophilic fasciitis patients produce significantly higher amounts of five cytokines, including interleukin (IL)–5 and interferon (IFN)–gamma.[6] IL-5 is known to activate mature eosinophils and to stimulate eosinophil chemotaxis, growth, and differentiation. IFN-gamma activates tissue macrophages and T cells. The findings of Dziadzio et al support increased levels of IL-5 in eosinophilic fasciitis, in addition to increased levels of transforming growth factor (TGF)–beta, another fibrogenic cytokine.[7]

Toquet et al investigated the phenotype of the lesional inflammatory cell infiltrate in patients with eosinophilic fasciitis and demonstrated a predominance of macrophages, CD8+ lymphocytes, and few eosinophils.[8] Pathologic specimens from patients with eosinophilic fasciitis demonstrate increased numbers of eosinophils, especially early in the disease course.

Taken together, the findings of these studies suggest a mechanistic framework marked by a proinflammatory and fibrogenic cytokine response with resultant tissue inflammatory cell infiltration.

In the tissues, the end effector cell of fibrosis is the fibroblast. Fibroblasts from lesional tissue of patients with eosinophilic fasciitis produce excess collagen in vitro and display elevated TGF-beta and type 1 collagen mRNA levels when examined via in situ hybridization with specific cDNA.[9, 10] Therefore, the pathogenesis appears to involve the concomitant increase in the expression of genes for TGF-beta and extracellular matrix proteins in fibroblasts in the affected tissues.

Mori et al suggested that an autocrine stimulatory loop involving major basic protein, a product of eosinophil degranulation, IL-6, which enhances collagen production and is induced my major basic protein, and TGF-beta could account for the progressive fibrosis seen in several eosinophil prominent disorders.[11]

Other studies showed elevated levels of serum manganese superoxide dismutase and tissue metalloproteinase 1 (TIMP-1) in eosinophilic fasciitis, suggesting a role in pathogenesis and providing a possible marker of disease activity.[12]

Fasciitis may be a common manifestation of various pathophysiologic processes associated with eosinophilia. The existence of primary and secondary forms of fasciitis has recently been suggested.

Understanding the mechanisms involved in the development of fascial inflammation and fibrosis in these conditions may yield insights into the pathogenesis of other fibrotic skin diseases.

Epidemiology

Frequency

United States

Eosinophilic fasciitis is very rare.

Mortality/Morbidity

No data are available on morbidity or mortality rates associated with eosinophilic fasciitis. Morbidity may result from joint contractures or carpal tunnel syndrome associated with fascial fibrosis. Rarely, a fatal aplastic anemia may develop.

Race

Eosinophilic fasciitis affects whites more often than it affects other races. It has been reported in African Americans, Africans, and Asians.[13, 14, 15, 16, 17]

Sex

In adults, eosinophilic fasciitis affects women more often than men.[18, 19, 20]

Age

The age range in eosinophilic fasciitis is 1-88 years, although most patients present during the third to sixth decades of life.[19] The average age of onset in two recent case series was 54.4 and 49.8 years.[19, 20]

Clinical Presentation    

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