I work for a veterinarian and my hubby works at the landfill. It seems one or the other of us always has some kind of rash we humorously refer to as "jungle rot".
I'm a big fan of a salve called Oto-Soothe, which I get at work. It's mainly prescribed for ear infection in dogs. It's an anti-fungal/bacterial. The stuff is wonderful.
Something else, your laundry soap and softener. I can't use any kind of softener, liquid or dryer sheets. All sweaty parts, plus anywhere bra, sock, underwear, waistbands, cuffs rub I turn red and it's like it's on fire. I've gotten up in the middle of the night and showered it's so bad.
I now use "All free and clear" and no softener. I realize changing soap isn't the answer to your question, but if you're using highly scented perfumy stuff and a lot of softener, changing to a non allergenic will at least not irritate the area more.
good luck!