@moylandavis Hello, I am 64 years old and live in Germany. However, I have not been able to find a support group here, and I have had aquagenic pruritus since early childhood. Since I have had the same symptoms my entire life and my daughter reports similar symptoms, I assume that it is genetic. I do not have polycythemia vera and am otherwise completely healthy metabolically and do a lot of sports. However, as far as I have researched, there have been no studies to date that have been able to identify a genetic cause. I have only recently become aware of treatment with ß-alanine; previously, I thought it might cause itching. As I am a neurologist myself and know that conventional medicine can do little to help, I would like to share my experience and thoughts on my symptoms. I hope not to hurt Community Guidelines so far. Please tell me if I made a mistake. As I´m not so firm in English, I made translation via Deepl.
After a cold shower or even in a swimming pool with cold water, intense itching quickly develops, lasting about half an hour to an hour and usually spreading to the whole body. The itching can also occur spontaneously, without contact with water, and can be triggered by slight mechanical stimuli. However, frequent triggers also include light sweating with or without cooling of the skin. The pruritus has the characteristic of spreading when scratched (for relief) and eventually covering the entire body. Over the years, I have found that extremely hot, almost painful showers provide relief, and I always check first in every hotel to see if the shower is hot enough. In addition, pregabalin 75 mg is relatively effective in preventing my itching, but I do not use it regularly. When the skin is well tanned in summer, the pruritus subsides very well overall. I have experienced this frequently during vacations in the Canary Islands. When landing in humid air, the itching occurs immediately, but after the vacation with a corresponding tan, there is no more pruritus.
If the pruritus starts in one area, e.g., the thigh or forearm, I can prevent it from spreading by using a very hot water bottle, which I sometimes do when the pruritus manifests itself at bedtime. A sauna with moist heat is not a problem. Exercising in a room below 20°C and sweating is a risk factor for triggering pruritus. Trying to exercise when pruritus is starting is pointless, as it becomes unbearable. However, it is usually possible to exercise despite sweating. Occasionally, I also have the impression that excessive coffee consumption promotes pruritus. When the pruritus subsides under the effect of heat, and sometimes when it subsides spontaneously, I feel a slight burning sensation that indicates improvement. Wearing cotton clothing after showering is beneficial. Recently, I tried ß-alanine because the symptoms were getting worse again. So far, 2*1250 mg seems to have had some effect. After the first dose, I felt a slight burning sensation on my face, but otherwise there were no negative effects.
I hope that ß-alanine remains effective in my case, as it can also be used as a training booster. I wish you continued success.
PS : I read the literature you posted and I´m interested in studies to elucidate a possible genetic background.

@moylandavis /@panache22

Hopefully, y'all both see my post. Thank you for the information on the Beta Alanine. I went to my dermatologist for severe itching with no rash on my torso and thighs. She said I have Pruritus and prescribed triamcinolone acetonide. It occurs every time I'm in the sun, as if I'm allergic. I know what you are thinking. However, I own a farm in South Carolina and avoiding the blazing, humid heat is not an option. I just want to know what is causing this terrible itch. My PCP ran blood tests but found nothing.