Recurring rashes in inner thighs

This has been an intermittent problem for a number of years, and seems to get worse every time summer comes around. In my area, the summertime heat brings high levels of sticky humidity and that seems to make it worse.

It's a rash in the inner upper thigh area, between the scrotum and anus, where the thighs rub together as I walk. Sometimes, it's so bad that I can't even walk because of it. Over the past few days, it's been getting worse.

Sometimes at night before I go to sleep, I'll rub some A&D diaper rash ointment on it and it will be okay for the next day. Baby powders and Gold Bond seem to work great in the morning for keeping the friction from creating pain, but that quickly wears off halfway through the day, probably through humidity and sweat.

It has to be some sort of heat- or friction-related rash, but I'm wondering if anyone's experienced it or what can be done about it.

If anyone can post some help, it would be greatly appreciated. Thanks in advance!

Dan