[Physical urticarias].

Abstract

Ten percent of chronic urticarias are physical urticarias. Patients suffering from physical urticaria all have a suggestive history with specific eliciting stimuli (cold, heat, water, sun.) and wheals in the areas where the stimulus acts. The involved pathomechanisms are not well known. An unknown allergen (related to a cold or a heat injury, a polar molecule contained in the stratum corneum and soluble into water, a photoallergen) could induce a mast cell mediator release, followed by an infiltration by eosinophil then neutrophils polymorphonuclears. T-cells are not highly involved. Dermographism, the most frequent can be cured by anti-H1. In diagnosing cholinergic urticaria physical exercise has to be done by the patient (jogging, running, riding), anti-H1 are efficient. In other physical urticarias (delayed-pressure, cold, solar, heat, vibratory urticarias) as to be managed as follows: (1) to perform specific tests with respectively (weights; ice cube; UVA, UVB and visible light exposure; hot water contained in a tube; a vortex mixer); (2) to avoid eliciting stimuli; (3) to treat the associated diseases e.g. in secondary cold urticaria; (4) to try to induce a physical tolerance, a review is enclosed concerning cold, solar, heat and aquagenic urticarias; (5) to associate or not non sedative 2(nd) generation antihistamines. All the other alternative treatments are discussed but none of them has been evaluated.