Aeroallergens linked to pathogenesis of eosinophilic oesophagitis
MedWire News: Aeroallergens may be involved in the pathogenesis of eosinophilic esophagitis (EoE), say researchers who found seasonal variations in diagnosis rates that correlated with pollen counts.
The pathogenesis of EoE is incompletely understood, but an association with food allergies, allergic rhinitis, asthma, and atopic dermatitis has been well described, say Fouad Moawad (Walter Reed Army Medical Center, Washington DC, USA) and colleagues. They add that aeroallergens have also been implicated as a contributing factor, but their contribution to the pathogenesis of EoE has not been confirmed.
To investigate, the researchers identified 127 patients (84% men), aged a median of 41 years, with confirmed EoE during 2006–2008. Daily pollen counts for grass, trees, and weeds were obtained from a certified monitoring station and compared with the number of EoE cases diagnosed per season.
The highest percentage of cases were diagnosed in the spring, while EoE diagnosis was least common in the winter months (33% vs 16%). The percentage of EoE cases diagnosed seasonally correlated positively and significantly with mean grass pollen count, but not with tree or weed pollen..
The team says that, although they were unable to determine the duration of EoE symptoms, they suspect that these follow a fluctuating course over the year, with exacerbation of symptoms during the high pollen months.
The researchers also found that a significantly greater number of EoE patients with seasonal allergies and atopic dermatitis presented in the spring time. However, asthmatics with EoE most often presented in the summer months, while the diagnosis of EoE in patients with food allergies remained constant throughout the year.
“EoE was still diagnosed during periods of lower atmospheric pollen concentrations and in patients without a history of atopic disease, which suggests a multi-factorial pathogenesis,” say Moawad et al.
The monthly variation in the number of upper endoscopies and clinic visits did not impact the likelihood of EoE diagnosis within a season. In addition, mean eosinophil counts in the proximal or distal esophagus were similar across all seasons.
“Future prospective studies with allergen sensitization testing may help further elucidate the exact relationship between aeroallergens and EoE,” writes the team in the journal Alimentary Pharmacology and Therapeutics.
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By Ingrid Grasmo