For a few months now my partner has had several round, red lesions on his thighs, calves, groin, backs of the knees and buttocks, ranging in size from a pimple to a dime (and much smaller red bumps on his forearms that look more like heat rash, except they've lasted as long). They itch, and some have white scales on them. Many of the ones on his calves and forearms have developed scabs from his scratching. They aren't contagious; we're together constantly and I have had none of these lesions.
At first his doctor called it ringworm, but when antifungal cream and oral medication had no effect he suggested it could be psoriasis or eczema. We've tried coal tar ointment, salicylic acid shampoo, even things like tea tree oil, vinegar, bleach and bloodroot! None seem to have any effect at all.
He doesn't drink coffee at all and takes in very little caffeine. He hasn't had excessive sun exposure. We think a few particularly humid days where he had to wear a suit for work and was sweating prodigiously might have triggered it.... but what is it and why won't it go away??
What else could it be, what other treatments should he try, how do we determine exactly what it is?
Thanks in advance for your help.