A systematic review of aquagenic urticaria - subgroups and treatment options
Published: May 6, 2022
Aquagenic urticaria (AquaU) is a rare variant of chronic inducible urticaria characterized by the occurrence of itchy wheals after exposure to water. The diagnosis of AquaU is confirmed by provocation testing. AquaU markedly affects many daily activities such as washing and taking a shower. Because of this, most patients experience a significant reduction of their quality of life. At present, little is known about the clinical manifestations of AquaU, and its treatment is a challenge.
In an effort to better understand AquaU subgroups as well as treatment options and outcomes, Rujithranawong and colleagues performed a systematic review, published in a recent issue of The Journal of Allergy and Clinical Immunology: In Practice. Related articles were searched by use of the terms “aquagenic urticaria” and “aquagenic angioedema” until June 2021 and reviewed according to Preferred Reporting Items for Systematic Reviews and Meta-analysis recommendations.
A total of 77 AquaU patients were investigated in 59 studies including 47 case reports and 12 case series. AquaU predominantly presented in women, and the mean age of onset of the disease was 20 years. Wheals commonly occurred in localized areas especially on the trunk and regardless of the water temperature. Based on the evidence, this systematic review proposed to classify AquaU into 2 subtypes, i.e. familial AquaU (which affects about 1 in 5 patients) and the more common acquired AquaU. Tap water was the most common reported trigger. Body fluids including sweat, saliva and tears were also reported to induce AquaU. For water challenge testing, tap water was most commonly used for testing. The provocation test should be performed at the trunk or sites previously reported to be affected by the patient.
Although many treatments were used in both subtypes of AquaU, second generation H1 antihistamine (2ndAH1) treatment is the recommended first-line therapy for both. Updosing of 2ndAH1 and omalizumab may be considered if symptoms are uncontrolled with a standard-dosed antihistamine. Phototherapy may be used in patients with refractory AquaU. The use of topical therapies in AquaU, which most commonly use hydrophobic vehicles, is poorly documented and of controversial efficacy. Further studies are required to fill the remaining knowledge gaps.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.
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