My 9 year old son has a rash that started in his arm pits. I thought it was an allergic reaction to antiperspirant so I had him discontinue use. He also developed the same type of rash in his crotch. He was also using an after shower deodorant powder. I had him discontinue use of that as well. The rash appears o be spreading. it consists of red itchy bumps that have a head, like a pimple, but very small. I gave Benadryl last night before bed, seemed to help.