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- Aquagenic pruritus is a rare condition characterized by intense itching, stinging, tingling, or burning sensations that occur immediately or within minutes after contact of the skin with water:
- Regardless of its temperature or source
- Without any visible skin changes such as wheals or rash.
- The pruritus usually begins within minutes of water exposure and can last for up to an hour or longer after water exposure.
- The itching most often occurs on the legs, followed by arms, chest, back, and abdomen, but typically spares the palms, soles, and mucous membranes.
- The discomfort can be so intense that individuals may avoid bathing or develop aversions to water due to psychological distress.
- Aquagenic pruritus can be idiopathic or associated with systemic diseases, most notably polycythemia vera and other myeloproliferative neoplasms, where it is a frequent and sometimes early symptom.
- The pathogenesis is not fully understood, but hypotheses include abnormal cutaneous nerve fiber function and the release of pruritogenic mediators (inappropriate mast cell degranulation with release of histamine or acetylcholine) upon water contact.
- Diagnosis is clinical, based on the characteristic history and absence of skin findings.
- Management is challenging; antihistamines are often ineffective, and treatment options include:
- Phototherapy (PUVA)
- Beta-blockers such as atenolol
- In the context of polycythemia vera, cytoreductive therapy or JAK2 inhibitors.