Under arm deodorants
I have irritation under both armpits, but especially my left one - Iím inclined to think that it is the deodorant I'm using, yet I have been using the same brand for years - there appears to be very small red lumps (pimples) under both arms.
The fact that you have been using the same deodorant for years does not exclude the possibility that it could be the cause of your problem. Deodorant sprays contain many chemicals any of which could cause your problem. Perfumes in particular are very potent sensitisers of the skin and with repeated application the skin can become sensitive to the particular perfume over time. However, I donít want to jump to conclusions and blame the spray. Alternatively you may have a minor infection of the skin in the armpit. It would be reasonable to stop using the spray and avoid using alternative deodorants to see if the irritation resolves spontaneously.