Hypereosinophilic Dermatitis: Successful Treatment with Dupilumab.

Hypereosinophilic dermatitis (HED) is a subtype of hypereosinophilic syndrome. HED is characterized by eosinophilic granulocytes increased in peripheral blood and bone marrow and infiltrated in skin. The clinical manifestations of HED are diffussed by erythema, papule and maculopapule with severe itching. The etiology of HED is unknown. At present, in addition to HED with FIP1L1-PDGFRA fusion gene positive, whose treatment is tyrosine kinase inhibitor, other types of HED first-line treatment are oral glucocorticoids, supplemented by antihistamines and immunosuppressants. Dupilumab is a human monoclonal antibody, which inhibits the IL-4 and IL-13 signaling by binding to the IL-4R-α and IL-13R-α-1 subunits of the receptor. We report a 76-year-old male patient with HED whose peripheral blood eosinophils decreased from 20.7% to 4.1% after 8 weeks of dupilumab, and his pruritus was completely relieved. Dupilumab was discontinued after 6 months of treatment. It is exciting that the patient has not experienced relapse for 17 months after the discontinuation. No adverse event was reported.