ABSTRACT
Infective gastroenteritis is by far the most common aetiology of sudden onset of diarrhoea, with or without vomiting in children. Although enteric viruses account for most cases in the developed world, bacterial and protozoal pathogens may also be responsible. Hypothetically a ‘slow onset’ food allergy may develop when intestinal immunity is compromised example during acute gastroenteritis or due to a longterm immunodeficiency that may predispose to excessive antigen absorption. Protracted diarrhoea with faltering growth that may commence in infancy after the neonatal period, or, less commonly, at any age throughout childhood. The onset often appears to be after acute infectious gastroenteritis with rapid resolution of symptoms in other affected family members. Loose, watery, frothy stools are produced following ingestion of milk, with perianal excoriation. It may develop following an acute infectious episode of gastroenteritis. Stool sugar chromatography identifies lactose in the stool.
