Epidemiology of food protein-induced enterocolitis syndrome

To summarize the epidemiology of food protein-induced enterocolitis syndrome (FPIES).

FPIES is regarded as a rare non-IgE-mediated gastrointestinal allergic disorder. Older nonpopulation-based studies reported an average of 1-15 cases presenting to allergy clinics a year, but recent studies have reported figures as high as 90 cases a year. The yearly incidence of FPIES in one Australian study was one in 10,000 infants less than 2 years of age. Chronic FPIES typically presents in neonates, whereas acute FPIES is primarily a disorder of young infants. FPIES has a slight male predominance; eczema and a family history of atopy are commonly present at diagnosis; almost one in 10 infants have coexistent IgE food allergies and siblings are rarely affected. There is regional variation in common triggering foods, rates of combined cow milk and soy FPIES and multiple food group FPIES. Understanding of the epidemiology of FPIES is limited by the lack of a universally accepted definition and the publication of few prospective population-based case series.

FPIES is not as rare as once thought, but how common it is, what factors predispose to its development, and why there is regional variation needs to be addressed by future well designed population-based studies?