She was well-appearing with palpebral conjunctival pallor and lacked lymphadenopathy, hepatosplenomegaly, or a rash. White blood cell count was 37.8 x 109/L with an eosinophilic predominance (71%), hemoglobin 7.7 g/dL (with MCV 53 fL and RDW of 22%), and platelet count 624,000 109/L. Her iron level was 211 ug/dL and transferrin was 313 mg/dL with a transferrin saturation of 5% and total iron binding capacity of 391 ug/dL. Lead level was 2.9 ug/dL. LDH and uric acid values were normal. A peripheral smear corroborated eosinophilia, a microcytic hypochromic anemia, and thrombocytosis. Stool was negative for ova and parasites.
With a high suspicion for Toxocara and pending serologies, our patient was discharged on a five-day course of albendazole with iron supplementation and scheduled for follow-up in the pediatric infectious disease clinic. After discharge, serologies returned positive for both Strongyloides and Toxocara antibodies. Unfortunately, our patient missed her follow-up appointment and when finally seen, her leukocytosis and severe eosinophilia remained unchanged. She had a mild cough, perhaps secondary to auto-infection from Strongyloides. She was no longer taking iron supplements and resumed eating soil, possibly leading to re-infection. She was re-treated with albendazole plus ivermectin, and her iron supplementation was resumed.
Discussion: Anemia and leukocytosis are common findings encountered by a pediatric hospitalist. In this case, the work-up of the iron deficiency secondary to excessive cow’s milk consumption revealed a severe eosinophilia that required the consideration of a broad differential including atopic and parasitic diseases, drug reactions, and malignancies. Her history of frequent outdoor play with dogs, pica, and eosinophilia raised suspicion for a parasitic disease. Although many helminths are known to cause eosinophilia, the confirmed diagnoses were the most probable prior to testing given that up to 14% of the population in the United States is seropositive for Toxocara, Strongyloidiasis is endemic in the southeastern United States, and both are transmitted through soil.
Conclusions: This case demonstrates the value of a thorough history (especially environmental) in the evaluation of eosinophilia. Not only is appropriate treatment (albendazole is the drug of choice for toxocariasis but is second to ivermectin for strongyloidiasis) important, but it must be emphasized that the treatment of iron deficiency and subsequent resolution of pica are key to preventing re-infections with certain parasites. Additionally, follow-up is vital, particularly when medication compliance and access are uncertain.