A debilitating dermal condition characterized by intense itching, stinging, tingling or burning sensations, without observable skin lesions, precipitated by contact with water at any temperature. Typically occurs after a shower with warm water. Reported in 5%-69% of patients with polycythemia vera (PV) (41.2% of patients in a recent study of 102 patients with PV). Notably, the onset of aquagenic pruritus precedes diagnosis of PV in almost half of cases.