OBJECTIVE:

To present a case of aquagenic urticaria and to review the literature regarding this very rare physical urticaria.

METHOD:

We described the clinical history of a patient with aquagenic urticaria. A water challenge test was performed, with plasma histamine levels measured before and after the challenge.

RESULT:

Our patient presented with a history of severe itching and wheals within five minutes of contact with water, regardless of its temperature or source (sea or tap water). A water challenge produced hives but serum histamine levels did not change. Prophylaxis with antihistamine or anticholinergic medications was not effective.

CONCLUSION:

Exposure to water can cause urticaria in susceptible patients and antihistamine and anticholinergic medication may not prevent the reaction. The mechanism of this phenomenon remains poorly understood.