A clinical case of secondary eosinophilia in a child

A couple of decades ago, the diagnostic search for the cause of blood eosinophilia concerned, mainly, the three major allergic diseases (bronchial asthma, allergic rhinitis, atopic dermatitis), or parasitic invasion. In recent years, more and more complex clinical syndromes, from reactive (secondary) eosinophilia to eosinophilic leukemia are increasingly considered by the doctors of different specialties. The aim of our work was to present a clinical case of secondary eosinophilia in a child with minimal clinical manifestations. Highlights: Sometimes blood eosinophilia in a patient is an “unexpected finding” for a physician, especially if the complaints are scanty, nonspecific, and objective examination does not reveal any significant health abnormalities. In the presented case, secondary (reactive) peripheral blood eosinophilia was diagnosed due to intestinal damage induced by food allergens. This clinical case is of practical interest to physicians, presenting a diagnostic search for the cause of blood eosinophilia, which eventually proved to be a mixed IgE/ non-IgE mediated food allergy manifesting as allergic enterocolitis. The IgE-mediated mechanism of food allergy is evidenced by a high level of IgE and its decrease with administered elimination diet; delayed-type response and low severity of clinical manifestations of food allergy, as well as blood eosinophilia suggest a non-IgE mediated food allergy. In this particular case, the severity of laboratory changes (blood eosinophilia, a significant increase in the levels of specific IgE) was associated with scarce intestinal symptoms. An opposite situation is observed, especially, in young children where the disease manifests with a pronounced clinical pattern of enterocolitis in the absence of laboratory changes.