Unique Presentation of Postpartum Hypereosinophilic Syndrome With Atypical Features and Therapeutic Challenges.

Background: Hypereosinophilic syndrome (HES) is an assemblage of disorders leading to marked eosinophilic tissue infiltration resulting in organ dysfunction. This case report describes a challenging diagnosis of HES identified in the postpartum period, a rare presentation of this disease process. Case Presentation: A 32-year-old active-duty service member with allergic rhinitis and childhood eczema developed a progressive pruritic rash and severe, recurrent epigastric pain with vomiting and weight loss 3 months following the birth of her first child. The patient gradually developed intermittent facial swelling, night sweats, and dyspnea, resulting in hospitalization. Two absolute eosinophil counts (AECs) taken more than a month apart ranged from 1600 to 4787 cells/μL. Mature eosinophils were found on skin, bone marrow, and duodenal biopsies. Radiography revealed no detectable neoplasm, and there was no clinical evidence of cardiac involvement. Testing revealed no mutations indicative of familial, myeloproliferative, or lymphocytic variants. The patient was started on empiric treatment with symptom improvement, which was gradually discontinued due to a second pregnancy. Conclusions: The patient described in this case met diagnostic criteria for HES; however, the complicated clinical and laboratory features made it challenging to characterize her disease as a specific HES variant, rendering it difficult to determine the optimal treatment regimen. Further therapy was complicated by a new pregnancy. It is important for clinicians to recognize an abnormally elevated AEC, promptly initiate systematic evaluation, and minimize delays in diagnosis and treatment of potential HES in order to avoid the extensive morbidity and mortality that can be associated with HES.