Successful treatment of a case of hypereosinophilia with suplatast tosilate monotherapy

Hypereosinophilia (HE) is a rare disease characterized by an increase in eosinophils. Suplatast tosilate is a selective Th2 cytokine inhibitor. This case report presents the course and prognosis of a patient with hypereosinophilia treated with suplatast tosilate monotherapy. A 41-year-old female patient who complained of "Elevated blood eosinophils were found during physical examination for more than 2 months" visited the Allergy Department. The systematic screening results of parasites, autoantibodies spectrum, tumor markers, peripheral blood morphology analysis, and leukemia fusion gene (FIP1L1-PDGFR α) were all negative. Gastrointestinal endoscopy only indicated mild gastritis. The dust mites and multiple fungal mixtures were weakly positive in intradermal tests. Finally diagnosed HE. After treatment with suplatast tosilate 2 months of 100mg three times daily, the blood eosinophils decreased to normal. Then, maintenance treatment with 50mg three times a day for 3 months. And without recurrence during nearly five years of follow-up. The report indicates that suplatast tosilate can reduce peripheral blood eosinophils levels in patients with HE, and may be a reliable option for individualized treatment of HE. However, there is still no consensus on whether suplatast tosilate can be used as a first-line treatment or as an adjuvant therapy to reduce the corticosteroids dosage for patients with eosinophilia, and further research is needed.