A retrospective cohort study of patients with eosinophilia referred to a tertiary centre

Introduction. Patients with eosinophilia (an increased number of eosinophilic granulocytes > 0.5 × 10⁹/l in the blood) are encountered in all medical specialties and frequently need thorough workup to identify the eliciting causes and decide whether treatment is indicated. In Denmark, highly specialised centres for eosinophilic diseases or conditions have been established to provide a foundation for the management of complicated cases. Here, we present experiences from such a multidisciplinary centre. Methods. This was a retrospective study of all patients seen in our tertiary centre for eosinophilia in the 2016-2019 period. Results. Referrals mainly derived from specialised secondary care and to a lesser degree from primary care physicians. Patients were either asymptomatic or exhibited symptoms from up to three organ systems and presented a median eosinophil count of 1.7 × 10⁹/l. Up to eight new clonality analyses or imaging studies per patient were performed after referral. One of these, T-cell receptor analysis, was performed frequently but provided limited information, whereas, e.g., flow cytometry proved more clinically applicable owing to its broader diagnostic range. In total, 51 patients were evaluated and classified as secondary (59%), myeloid neoplasm with PDGFRA rearrangement (2%), idiopathic hypereosinophilic syndrome (31%) and idiopathic hypereosinophilia (8%). Conclusion. The value of a multidisciplinary and versatile approach in a highly specialised centre has a positive impact on diagnostic processes as well as on the evaluation of treatment need.