Aquagenic Urticaria

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Swelling of the wrists (A) and ankles of 3 months' duration prompted a 33-year-old man to seek medical attention. The swelling was highly migratory, with periods of regression that lasted several days at a time. The patient also had a 3-year history of "breaking out" after contact with water. He had no personal or family history of asthma, allergies, or other atopic disorders. He was not taking any medications.

The rash occurred regardless of the water source or temperature. Within 5 to 10 minutes after water exposure, the skin of his upper arms, shoulders, and inner thighs became red and pruritic. Small, pale wheals then developed, particularly in the most vigorously scratched areas (B and C). Vesicles and pustules intermittently surfaced within these wheals. Occasionally, he deroofed the lesions, which led to bleeding or weeping ulcers. Postinflammatory hyperpigmentation was noted in well-circumscribed areas of prior ulceration; some areas had coalesced into large dark patches (D).

A complete blood cell count, rheumatoid factor, serum uric acid levels, and sedimentation rate were normal. Histamine was not measured because of the historical unreliability of the results.

Aquagenic urticaria was diagnosed; this rare condition is characterized by periods of intense pruritus with erythema and wheals after exposure to water. The lesions may vary in presentation. Aquagenic urticaria can occur after exposure to tap water, rainwater, salt water, and purified water.¹ A female predilection, prominence of dermatographism, normal serum IgE levels, and normal complement C1 esterase inhibitor levels have been reported.¹ One study showed no significant change overall in serum histamine levels during an urticarial reaction; however, levels may increase in some patients during the acute phase of the reaction. An association between lactose intolerance and aquagenic urticaria has been reported; however, this patient was not lactose intolerant.¹

Angioedema occurs in up to 50% of cases of chronic urticaria, but unlike hereditary angioedema, it rarely affects the larynx. Chronic urticaria can be exacerbated by aspirin, penicillin, angiotensin-converting enzyme inhibitors, opiates, alcohol, and stress.² This patient denied use of these drugs, and stress did not seem to be a contributing factor.

Urticaria can be IgE-mediated, complement-mediated, or nonimmune-mediated. In aquagenic urticaria, theoretically, water interacts with sebum in the corneal layer of the epidermis. This interaction forms a compound that mast cells recognize as foreign; the cells degranulate and release histamine.¹

The patient was treated with fexofenadine, once daily at night. He was also advised to avoid long showers. After 3 weeks with no change, fexofenadine was discontinued and hydroxyzine was started. Both the rash and swelling resolved after 2 weeks of continuous treatment. At the 4-month follow-up, he remained symptom-free with regular use of hydroxyzine.

Although antihistamine treatment typically relieves symptoms initially, a definitive cure remains elusive.³ The lack of response to fexofenadine in this patient was likely related to individual variability and not to overall ineffectiveness of nonsedating antihistamines.⁴

 

References:

REFERENCES:

1. Luong KV, Nguyen LT. Aquagenic urticaria: report of a case and review of the literature. Ann Allergy Asthma Immunol. 1998;80:483-485.
2. Charlesworth EN. Urticaria and angioedema: a clinical spectrum. Ann Allergy Asthma Immunol. 1996;76:484-495.
3. Muller BA. Urticaria and angioedema: a practical approach. Am Fam Physician. 2004;69:1123-1128.
4. Breneman DL. Cetirizine versus hydroxyzine and placebo in chronic idiopathic urticaria. Ann Pharmacother. 1996;30:1075-1079.