Seasonal Variation in Urticaria: The Role of Humidity, Pollen, and Environmental Modifiers

Abstract

Urticaria is a heterogeneous dermatological disorder characterized by transient wheals, angioedema, and pruritus, affecting up to 20% of individuals at least once during their lifetime. While many cases are idiopathic, a substantial proportion of patients report seasonal variation in disease activity, suggesting a contributory role of environmental factors. This narrative review examines the influence of humidity and pollen—two key seasonal environmental modifiers—on the onset and exacerbation of urticaria. Extremes of humidity can disrupt epidermal barrier integrity or promote sweat retention, thereby facilitating mast cell activation in chronic spontaneous and cholinergic urticaria. Seasonal pollen exposure, although classically associated with respiratory allergy, may act as an immune amplifier through IgE-mediated sensitization, cross-reactivity, and heightened mast cell reactivity in predisposed individuals. Additional seasonal contributors such as temperature extremes, viral infections, air pollution, and ultraviolet radiation are also discussed. Recognizing seasonal patterns in urticaria has important clinical implications, enabling anticipatory management through environmental modification, optimization of antihistamine therapy, and control of associated atopic comorbidities. Greater awareness of these modifiers may aid in reducing disease burden and improving quality of life in affected patients.

Keywords: Urticaria; Seasonal Variation; Humidity; Pollen; Environmental Triggers

Citation

Manocha G, Gulati S, Malhotra A, Gulati A. Seasonal Variation in Urticaria: The Role of Humidity, Pollen, and Environmental Modifiers. WebLog J Dermatol. wjd.2026.e1803. https://doi.org/10.5281/zenodo.20329315