[Localized salt-dependent aquagenic urticaria: A case report].

BACKGROUND: Aquagenic urticaria is a rare but well-known form of physical urticaria mainly affecting young women. It is characterised by the appearance of erythematous and pruritic plaques a few minutes after initial contact with water and irrespective of temperature. The physiopathology of this condition remains poorly understood. Herein, we report a case of localised aquagenic urticaria occurring solely on contact with seawater.

PATIENTS AND METHODS: A 32-year-old woman reported onset of erythematous and pruritic plaques, confined to the neck and lower part of the face, several minutes after the start of bathing in seawater. Skin tests were carried out by applying wet compresses soaked in seawater (37°C for 30 min) to the areas in which the skin reaction usually occurred. A control test using a compress soaked in fresh water was carried out under identical conditions. An urticaria reaction was noted in the areas in contact with seawater, but no reaction was seen in the areas coming into contact with fresh water. Antihistamines taken on the days of bathing proved ineffective.

DISCUSSION: A number of similar cases have been reported in the literature, enabling the characterisation of this particular form of aquagenic urticaria and allowing its principal characteristics to be defined. It appears to be dependent solely on the salt content of the water. It is reported by young women while bathing in seawater. The urticaria plaques show a predilection for the neck and lower part of the face, as in our case, as well as the shoulders on occasion. The efficacy of antihistamines is inconsistent. The prevalence of this as yet poorly known entity is doubtless underreported.