Q:

6/20/2012
We all have pruritic patients and know the differential diagnosis is long. I have a 35yo female with severe pruritis lasting 20 minutes with no associated rash only following a shower. Trials of antihistamines have been unsuccessful. It is not secondary to specific soaps, shampoos etc. All labs are completely normal. Any thoughts would be appreciated both with regard to diagnostic and therapeutic.

A:

Thank you for your inquiry.

As usual, when we do not clearly understand the pathogenesis of a condition and have no specific therapy, a number of therapeutic modalities have been suggested. Unfortunately, I have no personal experience with any of these because, although I have seen many patients who have pruritus after a shower, I have not found it necessary to treat them because they have not been severe enough to initiate any specific therapy.

So, the best I can do is offer you the reports that have claimed success in treating this disorder. As you can see from the abstracts copied below, ultraviolet B phototherapy, naltrexone, capsaicin, Psoralen photochemotherapy (PUVA), sodium bicarbonate baths, and propranolol have all been reported to improve the symptoms of this condition.

Thank you again for your inquiry and we hope this response is helpful to you.

Journal of the American Academy of Dermatology
Volume 13, Issue 1 , Pages 91-96, July 1985Abstract
The clinical characteristics of aquagenic pruritus (AP) based on a series of thirty-six patients are presented. AP is characterized by the development of severe, prickling-like skin discomfort that is without observable skin lesions and that is evoked by contact with water at any temperature. Other causes of pruritus associated with water contact must be excluded. In the thirty-six patients, skin discomfort developed within minutes of water contact in approximately half. In others, discomfort began 2 to 15 minutes after water exposure had ceased. The pruritus was usually generalized, lasting from 10 to 120 minutes (average, 40.6 minutes), and in 55% was associated with symptoms of acute emotional liability. There was no increased prevalence of atopy. Thirty-three percent reported a family history of water-related itching. Of fourteen patients treated with ultraviolet B phototherapy, eight (57%) noted significant relief. Of thirty-four patients, sixteen (47%) noted partial relief with oral antihistamine therapy. Patients with polycythemia rubra vera (PRV) may present with symptoms similar to those of AP, and all patients with symptoms consistent with AP should be investigated for the presence of PRV. (J Am Acad Dermatol 1985 Jul;13(1):91-6.

Journal of Cutaneous Medicine and Surgery: Incorporating Medical and Surgical Dermatology
Volume 9, Number 5 (2005), 215-216, DOI: 10.1007/s10227-005-0144-xAbstract
Background: Aquagenic pruritus is an intense prickling sensation that develops in affected individuals immediately after contact with water at any temperature. It is most commonly associated with polycythemia rubra vera. Common but often ineffective treatments include anticholinergics and antihistamines. Other moderately successful treatments include capsaicin cream, UVB phototherapy, and sodium bicarbonate bath water.
Objective: In this case report we describe a 55-year-old female with severe itching following showers. Underlying causes were ruled out with a series of blood tests, a chest X-ray, and serum protein electrophoresis. After multiple treatment failures, her itching was relieved with naltrexone.
Conclusion: Endogenous opiates, like naltrexone, can modify pruritus by influencing the peripheral and central sensation of itch. It has been found to be successful in suppressing the perception of pruritus from many diverse origins including aquagenic pruritus.

Journal of the American Academy of Dermatology
Volume 30, Issue 2 , Pages 232-235, February 1994Abstract
Background: Aquagenic pruritus is characterized by pruritus after contact with water; there are no objective cutaneous changes. Capsaicin, which induces the release of neuropeptides from A delta and C cutaneous nerve fibers, has been successfully used in the treatment of several dermatoses associated with pruritus. Among the many different neuropeptides present in human skin, the undecapeptide substance P has been shown to cause pruritus.
Objective: We evaluated the clinical effect and searched for alterations in cutaneous neuropeptidergic fibers before and after treatment with capsaicin cream.
Methods: Five patients with aquagenic pruritus were treated with capsaicin cream 0.025%, 0.5% or 1.0% three times daily for 4 weeks. Direct immunofluorescence (DIF) was performed before and after treatment to evaluate the storage of neuropeptides in the A delta and C type cutaneous nerve fibers.
Results: Before treatment (when by DIF the neuropeptidergic fibers appeared filled with neuropeptides), contact with water consistently provoked itching. After capsaicin treatment (when by DIF the neuropeptidergic fibers were depleted of neuropeptides), contact with water did not evoke pruritus. Areas of skin treated with the vehicle alone showed no clinical improvement or change in neuropeptide content.
Conclusion: This study suggests that neuropeptides, including substance P, may contribute to mediating the itch in aquagenic pruritus. (J Am Acad Dermatol 1994 Feb; 30(2 Pt 1):232-5).

British Journal of Dermatology
Volume 129, Issue 2, pages 163–165, August 1993
Summary Psoralen photochemotherapy (PUVA) was effective in the treatment of five patients with aquagenic pruritus, associated in one with polycythaemia rubra vera and in another with the myelodysplastic syndrome. Relapse occurred within 2–24 weeks when treatment was discontinued. Maintenance therapy or a further course of PUVA was necessary to maintain remission. This requirement may limit the value of the therapy.

Journal of the American Academy of Dermatology
Volume 18, Issue 5 , Pages 1081-1083, May 1988Abstract
We report our experience in the treatment of two patients with aquagenic pruritus of the elderly and two patients with aquagenic pruritus. Our findings confirm previous reports by others indicating that aquagenic pruritus is not one homogenous entity but rather is composed of two similar but distinct entities, each of which responds to a different treatment. Patients with aquagenic pruritus were helped by adding sodium bicarbonate to the bath water while patients with aquagenic pruritus of the elderly responded to emollients. It is suggested that aquagenic pruritus and aquagenic pruritus of the elderly are two similar but distinct entities. Separating these two entities provides the key to successful treatment, because each of them responds to a different treatment without crossover. This report is only the second report indicating the effectiveness of sodium bicarbonate baths in patients with aquagenic pruritus. It is clear that further examples are needed to confirm these findings. (J Am Acad Dermatol 1988 May;18(5 Pt 1):1081-3).

J Allergy Clin Immunol. 2011 Nov; 128(5):1113. Epub 2011 May 25. Treatment with propranolol of 6 patients with idiopathic aquagenic pruritus. Nosbaum A, Pecquet C, Bayrou O, Amsler E, Nicolas JF, Bérard F, Francès C.

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology