An eye witness perspective of the changing patterns of food allergy.

Food allergy may affect the gastrointestinal tract of children and adults too, albeit less commonly. The changing clinico-pathological expression of such food allergy in children over a 30 year period is related, from the eye witness perspective of a paediatric gastroenterologist in London. Tissue diagnosis by biopsy, related to dietary elimination and challenge has been the basis for the first clinico-pathological descriptions and accurate clinical diagnosis of these syndromes as they affect the gastrointestinal tract. In the 1970s cow's milk sensitive enteropathy presenting as chronic diarrhoea and failure to thrive in infancy often after infective gastroenteritis, especially with enteropathogenic Escherichia coli, was an important problem. By the late 1990s such presentations had become most uncommon in developed communities but they continue to occur in developing communities. By contrast in more recent times, multiple food allergy associated with minor small intestinal enteropathy and gastro-oesophageal reflux in older children has become an important clinical problem in children seen in developed communities. Accompanying these changes has been a dramatic fall in the number of children with clinically severe gastroenteritis with severe dehydration requiring hospital admission. Furthermore, the widespread diagnostic use of endoscopy of the upper and lower gastrointestinal tract in children with multiple biopsies has expanded gastroenterological diagnosis in children. This approach gives information about the oesophagus and ileo-colon not available in the earlier studies, which largely concentrated upon small intestinal biopsies, obtained by Crosby capsule biopsy. So, over this 30 year period clinico-pathological expression has altered but also the diagnostic approach has technically changed.