Eosinophilic oesophagitis: epidemiology, clinical aspects, and association to allergy.

Eosinophilic oesophagitis is characterised by age-dependent symptoms mimicking gastrooesophageal reflux disease, a distinct endoscopic appearance and a histological picture with extensive infiltration of eosinophils in the oesophageal mucosa. Eosinophilic oesophagitis is more frequently seen in males, and patients often belong to the paediatric or adolescence age groups. The exact prevalence of eosinophilic oesophagitis is unknown, but it has been suggested that the United States has a higher prevalence than Europe. Several treatment algorithms have been suggested, including elemental diets, oral steroids, inhaled (swallowed) steroids, and leucotriene receptor antagonists. Detailed information on the eosinophilic inflammatory processes in the oesophageal mucosa was initially obtained from animal models, in particular with regard to the role of interleukin-5 and the chemokine eotaxin-1 in eosinophilic recruitment. Studies have suggested a cytotoxic effect of eosinophilic degranulation products on nerve fibers in the gastric/intestinal mucosa, implicating a direct effect of allergic inflammation on gastrointestinal motility. Human studies recently have emphasized the role of eotaxin-3 and identified a single nucleotide polymorphism probably related to disease susceptibility.