Hi, this sounds like fluoride sensitivity to me. I had the same problem; I was getting dizzy in the shower, having heart palpitations, panic attacks, anxiety and much more. I found out it was fluoride in my public water. Fluoride concentrates and produces toxic fumes when it's heated.
I got the whole house water fluoride filter and I haven't gotten dizzy since.
Low blood pressure (hypotension) By Mayo Clinic Staff
When to seek medical advice
In many instances, low blood pressure isn't serious. If you have consistently low readings but feel fine, your doctor is likely to monitor you during routine exams. Even occasional dizziness or lightheadedness may be relatively minor — the result of mild dehydration, low blood sugar or too much time in the sun or a hot tub (MAYBE HOT SHOWER ALSO?), for example. In these situations, it's not a matter so much of how far, but of how quickly, your blood pressure drops. Still, it's important to see your doctor if you experience any signs or symptoms of hypotension because they sometimes can point to more serious problems. It can be helpful to keep a record of your symptoms, when they occur and what you were doing at the time. If these occur at times that may endanger you or others, you should talk to your doctor.
http://www.mayoclinic.com/health/low-blood-pressure/DS00590/DSECTION=when-to-seek-medical-advice
Some people with NCS or other Dysautonomia disorder experiences problems in the shower due to standing and the warm/hot water. They feel faint and may actually faint. I find it better for me to take baths. I also have RA and the hot water is nice on my joints, but I have to get out of the tub slowly.
Moving too quickly with NCS can cause lightheadedness as well.
Glad she is going to the doctor.
Keep us posted
PJ
Sounds like she showers in the morning? Before breakfast? What about a little low blood sugar? Tossing out thoughts.
Both my kids fainted in the shower when they were that age, a boy and a girl. This was 30 years ago so I'm sure there are better explanations today than I can speak to, but in both cases it was explained away as new hormones combined with physical stress the night before, both were exhausted when they went to bed. Both repeated the problem, same situations, and the doctor simply suggested a little coffee before showering as the warm water combined with being run down equaled fainting. Our family has a history of very slow heart beats. After drinking a bit of coffee, no more fainting spells.
Whats her heart rate during one of these episodes?