Uncovering a Severe Patient Group With Pollen-Related Extrarespiratory Allergic Symptoms: A Year-Long Diary Survey in Japan

Abstract

BackgroundThe most common symptoms of pollen allergy are rhinitis and conjunctivitis. However, in real-world clinical practice, we sometimes encounter patients with pollen allergy suffering from severe extrarespiratory symptoms including skin, gastrointestinal, or flu-like symptoms in relation to exposure to sensitized pollen. ObjectiveThe aim of this study was to elucidate the extrarespiratory symptoms in patients with pollen allergy MethodsWe performed a non-drug-focused, prospective study of patients with pollen allergy (n=384). During the 1-year observational period, they were asked to complete a weekly e-diary consisting of visual analogue scale (VAS) scores to assess all symptoms experienced in various organs over the past week. An association between seasonal pollen levels and seasonal increase in VAS scores was evaluated using a mixed-effect model for repeated measures. A k-means cluster analysis was performed to identify a group of patients experiencing stronger extrarespiratory symptoms. ResultsIn patients sensitized to grass or birch pollen, higher seasonal levels of these pollen grains were associated with higher VAS scores for headache, gastrointestinal symptoms, skin symptoms, and fatigue. A cluster analysis identified a group of severe pollen-allergic patients with higher extrarespiratory symptoms (n=42). This group was characterized by a higher frequency of comorbid food allergy/atopic dermatitis, higher rate of IgE-sensitization to pollens, and higher impaired activity and work productivity. ConclusionThis 1-year survey identified a small but non-negligible group of patients with pollen-related extrarespiratory symptoms. More attention should be paid to this patient group considering their impaired activity and work productivity.