[Aquadynia: a role for VIP?].

BACKGROUND: Aquadynia (water-related cutaneous pain) is a very rare disorder, recently described. CASE REPORT: A 40 year-old woman suffered from aquagenic pruritus, complicated by paresthesia and pain. There was no clinical argument in favor of a psychiatric disorder, Fabry's disease or any other disease. Clinical and histological cutaneous examinations were normal. Immunohistochemical study of neurotransmitters (substance P, calcitonin gene-related peptide or CGRP, vasoactive intestinal peptide or VIP, somatostatine) did not show any modification in nerve density. However, VIP-immunoreactive epidermal cells were observed. Electromyography and study of somesthesic-evoked potentials were normal. No treatment had provided any efficacy. Clonidine and capsaicin had been prescribed with partial success. DISCUSSION: Three other cases of aquadynia have been reported. Differential diagnoses of aquadynia are aquagenic pruritus and urticaria, hysteria or simulation, Fabry's disease, erythermalgia, peripheral neuropathy or polycythemia vera. The presence of VIP-immunoreactive cells suggests that VIP could be produced by these cells after contact with water. The effects of propanolol and clonidine on aquadynia are in favor of an adrenal component.