I have a red rash in my left armpit. When this has happened before, I have simply kept it clean and avoided deodorant and anti-perspirant for a few days, and all is well. This happened a few times a year. I almost always use deodorant based on mineral salt: very natural.
However, this time I left it alone except keeping it clean, and it did not go away after almost two weeks. Thinking it might be bacterial, I applied Neosporin after cleaning, but this made little difference after a few days. So next, thinking it might be fungal, I applied 2% Miconazole Nitrate creem after cleaning, and again, this made little difference.
What next? Working at home to care for my mother, I usually shower every other day, I do not sweat heavily, am only a little overweight, use glycerin soap, and mineral salt based deodorant. My right armpit has no similar problem. This is the first time that cleaning and avoiding deodorants for a few days has not solved the problem.
In the mean time, I will try washing twice a day and see what happens.