Why are my armpits so itchy and red!

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Hello, I know that you have done a lot of research on odor of the armpit, but I was wondering if you have any ideas on why my armpits are itchy. Ever since I was like 13 my armpits have been very itchy (and of course I itch them so they are always red and irritated). I am 23 now and still have this problem. I have tried almost every brand of deodorant I can find, a lot of the natural ones did not protect me from scent and some of them burned. When I wear deodorant it is itchy/painful but it does stop me from smelling. I have been to multiple doctors from different fields and no one knows what is going on. My most recent dermatologist took a sample of my skin under my armpit and tested it in his lab. He said that I was allergic to aluminum zirconium tetrachloride. I bought a deodorant without this and for a while the itching stopped! It was amazing my armpits went back to normal looking, but unfortunately it didn't last forever and I am having the problem again even with multiple different deodorants that do not have that ingredient. I have even tried deodorant without aluminum or zirconium with no luck. Any ideas or tips would be greatly appreciated!!