Background: Eosinophilic oesophagitis is thought to be an isolated oesophageal disease associated with biopsy-verified eosinophilia of the squamous cell epithelium of the oesophagus. Food- or aeroallergens have been suggested to be the cause of eosinophilic oesophagitis; however, as these allergens pass through the pharynx sharing the same squamous cell epithelium, eosinophilic infiltration could be expected also here. Whether this is true or not has hitherto not been clarified.
Aim: To find out whether eosinophilia is present also within the pharyngeal epithelium in patients with eosinophilic oesophagitis.
Methods: In all, 10 patients (median age 34, range 15-70) with biopsy-verified eosinophilic oesophagitis [peak count >20 eosinophils per high power field (hpf)] were biopsied also in the pharynx. The biopsies underwent histopathological examination and at each level, the peak number of eosinophils per hpf was counted.
Results: None of the patients examined was found to have eosinophilia within the squamous cell epithelium of the pharynx (median peak count 0, range 0-1).
Conclusions: The pronounced eosinophilic infiltration in eosinophilic oesophagitis appears to be an isolated oesophageal phenomenon not shared by the adjoining organ sites and in particular, not by the pharynx. This may have implications for future research.