Aquagenic pruritus explained

Aquagenic pruritus is a skin condition characterized by the development of severe, intense, prickling-like epidermal itching without observable skin lesions and evoked by contact with water.^{[1] [2]}

Presentation

Presentation varies from person to person. Some people have discrete attacks, which can last between 10 and 120 minutes^[3] while others are symptomatic almost constantly due to atmospheric humidity levels and/or sweating. Itching most frequently occurs on the legs, arms, chest, back, and abdomen, though it can also occur elsewhere.^[4]

Itching on contact with water that also includes hives is known as aquagenic urticaria.

Pathogenesis

The exact mechanism of the condition is unknown. Some studies have suggested the itching occurs in response to increased fibrinolytic activity in the skin,^{[5] [6]} inappropriate activation of the sympathetic nervous system,^[7] increased activity of acetylcholinesterase,^{[8] [9]} or an increase in mast cell degranulation that releases histamine and other chemicals into the body.^[10]

Diagnosis

No definitive medical test is known for aquagenic pruritus. Rather, diagnosis is made by excluding all other possible causes of the patient's itching, including polycythemia vera. Since pruritus is a symptom of many serious diseases, it is important to rule out other causes before making a final diagnosis.^[11]

Treatment

Beta-Alanine, a nonessential amino acid and freely available as a nutritional supplement in many countries, has been found to suppress or significantly reduce the symptoms in many cases.^[12] Anecdotal evidence indicates that it is commonly consumed in doses of 750 mg to 2 grams before water contact.^[13] A study found that a dose of 2 grams twice per day led to a "dramatic and sustained improvement" of symptoms in a 13-year-old male patient, allowing him to comfortably shower, exercise, and swim.^[12]

Other treatment is usually focused on topical itch management. This can be effected by the application of hot water at the end of a bath or shower, antipruritic lotions or creams such as lotion containing capsaicin, using phototherapy, or the application of hot or cold packs to the skin after water contact.^[14] Paradoxically, hot baths or showers help many patients, possibly because heat causes mast cells in the skin to release their supply of histamine and to remain depleted for up to 24 hours afterward.^{[15] [16]}

H1 and H2 blockers, such as loratadine, doxepin, or cimetidine, have historically been the first line of pharmacological treatment, but not all people find relief with these medications. When antihistamines do work, loratadine seems to be the most effective for mild cases and doxepin most effective for more severe cases.

Naltrexone, hydrocortisone, or propranolol may relieve itching for some people.^{[17] [7]}

Sertraline or other Selective serotonin reuptake inhibitors (SSRIs) is also a line of treatment.Gabapentin is very helpful.

Etymology

The name is derived from Latin: aquagenic, meaning water-induced, and pruritus, meaning itch.

See also

• Aquadynia
• Aquagenic urticaria
• List of cutaneous conditions
• List of allergies

Further reading

• Steinman HK, Greaves MW . Aquagenic pruritus . Journal of the American Academy of Dermatology . 13 . 1 . 91–96 . July 1985 . 2411768 . 10.1016/S0190-9622(85)70149-1 .
• Web site: Office of Rare Diseases Research . National Institute of Health . Aquagenic pruritus . 18 April 2012.
• Salami TA, Samuel SO, Eze KC, Irekpita E, Oziegbe E, Momoh MO . Prevalence and characteristics of aquagenic pruritus in a young African population . BMC Dermatology . 9 . 4 . April 2009 . 19374742 . 2673209 . 10.1186/1471-5945-9-4 . free .
• Santoso I, Santoso-Pham JC . September 1999 . Aquagenic Pruritus: Two Cases That Resolved with Histamine₁ and Histamine₂ Antagonists . Hospital Physician . 67–8.
• Web site: Aquagenic Pruritus. Family Practice Notebook. 14 June 2020. dead. https://web.archive.org/web/20130508200621/http://www.fpnotebook.com/Sports/DER/AqgncPrts.htm. 8 May 2013.
• News: Boodman SG . May 16, 2011 . Common symptom, uncommon cause . Washington Post . 3 Jul 2012.
• Sekine R, Satoh T, Takaoka A, Saeki K, Yokozeki H . Anti pruritic effects of topical crotamiton, capsaicin, and a corticosteroid on pruritogen-induced scratching behavior . Experimental Dermatology . 21 . 3 . 201–204 . March 2012 . 22379965 . 10.1111/j.1600-0625.2011.01433.x . 23982356 .

Notes and References

1. Book: Freedberg IM, Eisen AZ, Wolff K, Austen KF, Goldsmith LA, Katz SI . 2003 . Fitzpatrick's Dermatology in General Medicine . 6th . McGraw-Hill . 401 . 978-0-07-138066-9.
2. Book: James WD, Berger TG, Elston DM . 2005 . Andrews' Diseases of the Skin: Clinical Dermatology . 10th . Saunders . 978-0-7216-2921-6 . 56.
3. Steinman HK, Greaves MW . Aquagenic pruritus . Journal of the American Academy of Dermatology . 13 . 1 . 91–96 . July 1985 . 2411768 . 10.1016/S0190-9622(85)70149-1 .
4. Web site: Aquagenic pruritus . U.S. Department of Health and Human Services.
5. Sekar CS, Srinivas CR, Jacob S . Aquagenic pruritus: beneath water "lies" . Indian Journal of Dermatology . 56 . 4 . 446–447 . July 2011 . 21965864 . 3179019 . 10.4103/0019-5154.84734 . free .
6. Lotti T, Steinman HK, Greaves MW, Fabbri P, Brunetti L, Panconesi E . Increased cutaneous fibrinolytic activity in aquagenic pruritus . International Journal of Dermatology . 25 . 8 . 508–510 . October 1986 . 3771051 . 10.1111/j.1365-4362.1986.tb00863.x . 41847126 .
7. Nosbaum A, Pecquet C, Bayrou O, Amsler E, Nicolas JF, Bérard F, Francès C . Treatment with propranolol of 6 patients with idiopathic aquagenic pruritus . The Journal of Allergy and Clinical Immunology . 128 . 5 . 1113 . November 2011 . 21616525 . 10.1016/j.jaci.2011.05.001 .
8. Bircher AJ, Meier-Ruge W . Aquagenic pruritus. Water-induced activation of acetylcholinesterase . Archives of Dermatology . 124 . 1 . 84–89 . January 1988 . 3337547 . 10.1001/archderm.1988.01670010048020 .
9. Kligman AM, Greaves MW, Steinman H . Water-induced itching without cutaneous signs. Aquagenic pruritus . Archives of Dermatology . 122 . 2 . 183–186 . February 1986 . 3947125 . 10.1001/archderm.1986.01660140073021 .
10. Web site: Aquagenic pruritus Genetic and Rare Diseases Information Center (GARD) – an NCATS Program. 2020-12-03. rarediseases.info.nih.gov.
11. Butler DF . James WD . Aug 17, 2018 . Pruritus and Systemic Disease . Medscape.
12. Friedlander MS, Admani S . Aquagenic pruritus in an adolescent effectively managed with β-alanine supplementation . Pediatric Dermatology . 38 . 1 . 320–321 . January 2021 . 33170524 . 10.1111/pde.14440 . 226297428 .
13. https://www.facebook.com/groups/230640150306723/
14. Holme SA, Anstey AV . Aquagenic pruritus responding to intermittent photochemotherapy . Clinical and Experimental Dermatology . 26 . 1 . 40–41 . January 2001 . 11260176 . 10.1046/j.1365-2230.2001.00757.x . 7564543 .
15. Web site: People's Pharmacy. Hot Water for Itches. 25 July 2012. 2012-06-18.
16. Book: Sulzberger MB . Dermatology: Diagnosis and Treatment . 1961 . Year Book Publishers . Chicago . 978-0801648083 . 94 . 2nd . 11 September 2018.
17. Ingber S, Cohen PD . Successful treatment of refractory aquagenic pruritus with naltrexone . Journal of Cutaneous Medicine and Surgery . 9 . 5 . 215–216 . October 2005 . 16502200 . 10.1007/s10227-005-0144-x . 24439125 .