THE SPECTRUM of disorders characterized by peripheral blood and/or tissue eosinophilia is diverse and heterogeneous. The relative paucity of these diseases has limited the ability to better define clinical subsets, origin, mechanisms of tissue injury, and the development of pathogenically determined therapeutic intervention. Nevertheless, clinical and laboratory data emerging over the past several years have provided important evidence that these illnesses are mediated by cytokines specific to the production, migration, and activation of the eosinophil.
The currently recognized systemic eosinophilic syndromes (unrelated to infectious and neoplastic disease) are distinguished from each other by their clinical and pathological manifestations. Target organ involvement may be localized and benign or generalized, associated with systemic manifestations, and potentially fatal. Diffuse fasciitis with eosinophilia (DFE) (eosinophilic fasciitis or Schulman syndrome) is a sclerodermalike condition characterized by inflammation and fibrous thickening of the subcutaneous fascia.1 Although involvement is generally limited to the skin, more widespread features