EF presents similarly to localized scleroderma and SSc. All 3 diseases can present with indurated plaques involving the upper and lower extremities. EF can be differentiated from these conditions by clinical, laboratory, and histopathological findings. Clinically, EF presents as a symmetrical, bilateral circumferential swelling and induration of the bilateral upper and lower extremities.
1 The involvement in EF occurs predominantly on the distal extremities (forearms, lower legs) but can also spread proximally and centrally to involve the trunk. It generally spares the hands, feet, and face.
2 Early in the disease course, EF can present with prominent swelling, pain, and redness. Fever and fatigue are present in most patients.
2 Induration becomes more prominent in later stages.
1 The skin of affected areas can exhibit a peau d’orange appearance due to edema of the underlying deep dermis, subcutaneous tissue, fascia, and/or muscle. A characteristic “groove sign” appears on elevation of affected limbs due to depression of the superficial veins overlying the fascial edema.
3 The peau d’orange appearance and groove sign in EF can differentiate it from localized scleroderma and SSc. Additionally, EF presents symmetrically and bilaterally, whereas localized scleroderma presents unilaterally.
1 Importantly, EF can be complicated by localized scleroderma in 20% to 30% of cases.
1 Clinically, EF can be differentiated from SSc by the absence of Raynaud’s phenomenon, sclerodactyly, and by the absence of nail fold capillary abnormalities. EF rarely affects internal organs, in contrast to SSc.
3 Moreover, the skin in SSc is smooth and shiny (in contrast to the peau d’orange appearance in EF) and can affect the hands, feet, and face, whereas these areas are spared in EF.
2 Differentiating EF from SSc is integral, as the diagnostic criteria for EF include the exclusion of SSc.
2EF can also be differentiated from localized scleroderma and SSc by laboratory findings. Eosinophilia is present in most (63%–86%) patients with EF, although it is not required for diagnosis and can appear transiently during the acute stages of the disease.
3 Eosinophilia is rare in SSc (~ 7%) and atypical in localized scleroderma.
3,4 Erythrocyte sedimentation rate can be elevated in EF, although specific SSc markers (anti-RNA polymerase III, antitopoisomerase-I, anticentromere antibodies) are usually absent but can be positive in 15% to 20% of patients.
2,3 EF can present with positive antinuclear antibody or rheumatoid factor in 10% of cases and elevated serum aldolase in 60%, the latter of which can serve as a marker of disease severity (
Table).
1,3The gold standard diagnostic tool for EF is en bloc skin to fascial biopsy.
2 Histopathology usually reveals fascial edema and inflammatory cell infiltration by plasma cells and lymphocytes; eosinophilic infiltration may be present in early stages.
1 Moreover, the diagnosis of EF can be made in the absence of classic histopathological findings. In such cases, an MRI of the involved areas can be used to support the diagnosis. MRI in EF reveals fascial edema and inflammation.
3 MRI may also guide the selection of optimal biopsy sites. Further, MRI can be used to evaluate disease activity and response to treatment.
1,3 In cases where MRI is unavailable or contraindicated, a CT scan, positron emission tomography scan, or ultrasound should be ordered.
2,3