Physical urticaria is considered a subgroup of chronic urticaria (CU) and is characterized by lesions reproducibly triggered by physical stimuli, including cold, heat, physical pressure, vibration, sunlight, water, and exercise. This physical stimulation of the skin incites the characteristic pruritic wheal and flare (ie, hive) response characteristic of urticaria; physical triggers also can provoke angioedema. Physical urticaria can occur alone or concomitantly with other types of chronic or spontaneous urticarial syndromes. The exact pathogenesis of the various physical urticarial syndromes is unknown. The diagnosis of physical urticaria is established by history and physical examination, and in many physical urticaria subtypes, the diagnosis can be confirmed by specific skin provocation testing. As with CU in general, the goals of treatment of physical urticaria are focused on symptom control from identifying and avoiding provocative physical stimulation and from managing symptoms with medical therapy to maximize symptom relief with the least possible toxicity.Strategies and EvidenceThe prevalence of physical urticaria is likely underestimated in the general population. Less severe cases may not come to medical attention or may be treated by primary care providers and thus under-reported. Studies on physical urticaria in the literature are derived largely from specialist experience at tertiary care centers,predisposing to centripetal bias in reports of the severity and duration of the various physical urticarial syndromes. With this in mind, up to 0.5% of the general population has been estimated to have a physical urticaria/angioedema condition and in up to 20% of patients with CU a physical urticaria component is present.The prevalence of the various physical urticaria syndromes also varies. Simple dermatographism, a subgroup of dermatographic urticaria, is likely the most common form of physical urticaria, occurring in up to 5% of the general population.3 Cholinergic urticaria is also common, accounting for approximately 5% of all cases of CU and up to 30% of all cases of physical urticaria.4 It affects the 2 sexes equally.5 Delayed pressure urticaria and angioedema (DPUA) has been described in up to one third of all patients with CU.
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