My mother had this condition. I remember as a child watching her after she got out of the shower, it was awful. Her doctor told her she was allergic to water. Then when I got pregnant with my first son (23 years old) it happened to me. It was terrible. My husband thought I was crazy and that it was in my head. Now I'm almost 50 and two of my boys have this condition. So I can definitely tell you it is hereditary. It has gotten better with age. Although now that I'm in menopause my hot flashes are triggering the stinging attacks. There is a medicine that helps and I'm living proof, it's Gabapentin and/or Neurontin. As long as I take one before I shower I will not sting. This medicine works better and faster than Benadryl. I found out about Gabapentin by accident. I had injured my right hip very badly and was having severe sciatic nerve pain and was put on Gabapentin and my itching/stinging was gone. There is hope. Talk to your doctor. Never take a hot shower, it will make it worse. Yes cool air does help but for me it does not stop it fast enough. From someone who lives in middle Georgia and the humidity is a killer, I have opted for the meds.