Allergy consult for eosinophilia in an infant

Specialists in allergy/immunology are often asked to evaluate patients with eosinophilia, with the general assumption of an underlying allergic or immunologic disease. We present a case of an infant referred for marked eosinophilia. Although atopic disease may be in the differential diagnosis, it is rarely associated with hypereosinophilia, and other conditions need to be investigated. Until the underlying cause is identified, systemic corticosteroid therapy may be initiated, mainly in severe cases.