It could be yeast, or just irritation. You can try over-the-counter 1% clotrimazole twice a day for a week--that should kill any yeasts that are there, if there are any. Beyond that, I'd just let the redness take care of itself. If it gets worse or doesn't go away, you can show it to a doctor. I don't think the other skin conditions you have are relevant.
Yeasts, by the way, are usually not contracted from someone else-. They live in the gut and mind their own business.
But I still don't think it's yeast.
Take care.
Dr. Rockoff