Persistent underarm rash

[Bossa09]

Just wondering if anyone on here had had a persistent underarm spots / rash?
I’ve had mines on and off since last May. Been on multiple rounds of antibiotics. It’s sore, itchy and unsightly.
Done all the bits to stop it. It comes without shaving however always after. I sweat a normal amount, changed and stopped deodorant for a bit. Stopped shaving, tried hair removal cream, then stopped altogether for a bit.
I will use a different razor each time and not for underarms and elsewhere.Tried multiple creams, I am genuinely baffled by what’s causing it.
It’s one side, not both.
Has anyone experienced this and managed to sort it out?

I'd possibly consider laser hair removal. If you get rid of the hair follicles then there's less chance of irritation.

I use a home IPL system. I used to get very stubbly and irritated underarms. Now the hair has been removed with the IPL they are completely smooth and clear of any irritation.