Cholinergic urticaria is characterized by small pruritic papules triggered by exercise, emotions, hot environments, or hot food and beverages. The pathophysiology remains unclear, but one hypothesis is that a central temperature increase plays a key role. A pilot study conducted at university hospital center (CHU) of Montpellier found that infrared exposure triggered symptoms in some patients with cholinergic urticaria. The infrared source was the same as that commonly used in photobiological tests.
The objective of this study is to identify the proportion of patients who develop cholinergic urticaria when exposed to infrared light. the investigators then aim to determine whether these patients have specific clinical or epidemiological characteristics that would allow them to be classified as a distinct subgroup of cholinergic urticaria and to assess whether sensitivity to infrared light is a prognostic marker of disease severity. Furthermore, measuring the core temperature of all patients during infrared light exposure will help determine whether patients sensitive to infrared light experience a greater increase in core temperature during the IR test. This would support the hypothesis that an increase in core temperature is responsible for triggering cholinergic urticaria flare-ups in this subgroup.
A better understanding of this condition and the identification of different subgroups could ultimately, with additional studies, allow for a personalized approach to patient management based on the cholinergic urticaria subgroup and each subgroup's sensitivity to different treatments.
