The association between seasonality and diagnosis and/or recrudescence of EoE has been a matter of controversy in the medical literature. Some earlier studies demonstrated a increase in the diagnosis of new cases during the outdoor seasons (mainly spring and summer), and this fact led to researchers to propose a potential role for aeroallergens in triggering EoE. However, more recent studies excluded this seasonal variation, by showing that the new EoE patients distributed equally allong the year.
This important topic has been recently addressed by a group of researchers, that undertook a systematic review of the literature related with the seasonal apearance of EoE. The researches carried out an exhaustive search of all the published evidences on the season when EoE patients were diagnosed, and how their food impaction episodes were distrubuted along the year. The search was done in the most important bibliographical databases and abstracts books of the major Gastroenterology and Allergy international meetings.
After revising an overall of 1,078 references found, data was finally collected from 18 studies, which included a total of 16,846 EoE patients. Of all new cases of EoE diagnosed per year, 27.1% were diagnosed in spring and 21.5% in winter, with no overall statistical differences in the annual seasonal distribution of newly diagnosed EoE cases demonstrated with the appropiate statistical tests.
Similarly, a homogenous distribution of episodes of EoE recrudescence (clinally manifested by food impaction episodes) throughout the year was noted, with no significant differences between seasons.
The authors did not found a significant publication bias in their research, which reduces the risk of not having recovered all the relevant information on this topic.
In their new article recently published in Allergy (The European Journal of Allergy and Clinical Immunology), the research team explain that a higher opportunity for achieving a diagnosis of EoE in a patient with chronic esophageal symptoms who also suffer atopic recrudescence during the pollen season may explain, among other reasons presented in the discussion section of the paper, the seasonal differences shown in some previous research. Any case, the authors recognize that airborne allergens may still have a certain role in triggering and maintaining EoE, but this fact is restricted to a very little group of patients.
Article reference: Lucendo AJ, Arias Á, Redondo-González O, González-Cervera J. Seasonal distribution of initial diagnosis and clinical recrudescence of eosinophilic esophagitis: a systematic review and meta-analysis. Allergy. doi: 10.1111/all.12767.