Practical Approach to Children Presenting with Eosinophila and Hypereosinophilia

Abstract

Eosinophilia is not a rare finding in clinical practice, and often poses problems in terms of etiologic research and differential diagnosis. Peripheral eosinophilia is defined by a blood eosinophil count > 500 cells/μL. It is classified into mild (500-1500 cells/μl), moderate (1500-5000 cells/μl) and severe for an eosinophil count > 5000 cells /μl. The term "hypereosinophilia” defines a condition characterized by a blood eosinophil count >1500 cells/μl in at least two consecutive tests made with a minimum of a 4-week interval. The causes of eosinophilia are various, and can be summarized by the acronym “APLV” which refers to Allergic disorders, Parasitic infections, Leukemia/ Lymphomas (and solid tumors) and Vasculitis-Immunodeficiency diseases, with allergic disorders and parasitic infections representing the most commonly identified causes. Allergic disorders are usually associated with mild eosinophilia, whereas values >20.000 cell/μl are highly suggestive for myeloproliferative disorders. Eosinophils may also be directly responsible for organ damage, mainly at cardiac, pulmonary and cutaneous level, deriving from the release of the granule products, of lipidic mediators and cytokines. Therefore, in the physician’s approach to a patient with persistent hypereosinophilia, it is also important to investigate the presence of organ involvement. In this review, we propose a diagnostic algorithm for children presenting with either blood eosinophilia or hypereosinophilia. This algorithm focuses on the patient’s history and clinical manifestations as the first step and the level and persistence of blood eosinophilia as the second, and this can help the physician to identify patients presenting with an elevated blood eosinophil count that need further laboratory or instrumental investigations.

Eosinophilia in Migrant Children

“…25 While certain etiologies found in this study are well-accepted causes of eosinophilia (helminths, Schistosoma , Strongyloides , and Toxocara 13,18,19,26–28 ), others are controversial. Protozoa are not commonly linked to eosinophilia, but Isospora belli, Sarcocystis and Dientamoeba fragilis 5,6,28,29 have been reported to induce eosinophilia. Additionally, Campylobacter and Shigella , 30 mycobacterial infections 28 and scabies 14 have been suggested to produce eosinophilia.…”

“…1 Organ involvement cannot, however, be accurately predicted by absolute eosinophil counts, and, therefore, even mild eosinophilia deserves study. [4][5][6] Among other diagnostic tests used for the screening of imported diseases, peripheral blood eosinophil counts are recommended for adults 2,7 and children. 6 Helminths are known to cause eosinophilia.…”

“…1 Organ involvement cannot, however, be accurately predicted by absolute eosinophil counts, and, therefore, even mild eosinophilia deserves study. 4–6…”

Severe eosinophilia in hospitalized patients

“…The differential diagnosis requires a thorough review of patient history, physical examination, and laboratory evaluation [2], while eosinophil levels constitute a helpful clue in the search for a diagnosis [3]. For example, mild increases of 0.5-1.5 × 10 9 /L may represent atopic disorders such as atopic dermatitis, allergic rhinitis, and asthma [4]. Conversely, severe eosinophilia (SE), exceeding 5 × 10 9 /L, is more likely to accompany hematologic disorders [5], severe drug reactions, and vasculitis.…”