Q: I have a red, itchy rash under my armpit. I work out a lot. Could it be from sweating?
It is difficult to say exactly what is causing the itching you are experiencing without seeing the rash in person. However, there are a few possibilities of what commonly cause an itchy rash in an individual’s armpits.
First, an allergic contact dermatitis can develop secondary to products, like from antiperspirants and deodorants that are used in the area. Irritant contact dermatitis or an allergic contact dermatitis can also result from deodorant soaps or other products that are used in cleansing the skin if they are not washed off completely, because the skin of the armpits is very thin.
Finally, a skin condition called erythrasma, which can be very itchy, can be found in the armpits. Erythrasma is often found in areas of excessive sweating, like the groin or armpits. It is caused by a superficial bacterial infection with Corynebacterium species. Erythrasma can be treated with prescription topical or oral antibiotics.