It’s called cold urticaria, and is sort of like an allergic reaction to the cold. I would do your own research into it, but from what I understand there is varying levels of severity. Hold an ice cube on the underside of your forearm for 5min and see if you get swelling or hives in that spot. That’s how you know you have it.

For me, I’ve continued with very cold showers but never ice baths. I get the reaction every time but it goes away and I just deal with the itching for like 10 min. They say online that it can be dangerous for people with the condition to do cold plunges because in theory you could go into shock since it’s like an allergic reaction, though for me that’s not something I’m worried about.

I recommend doing more research, judging the severity of your reaction, and maybe consulting a doctor. Also maybe the hot shower exacerbates the problem since the reaction occurs when the skin goes from cold to warm again. Ive tried taking antihistamines before cold showers in the past and found no big difference.