Hello,
It can be due to irritated skin and dryness of skin. It can be due to contact with cloth of underwear, sweating, abrasions or contact with detergents or soaps. If the area if itchy or there is some white discharge then we can think of a fungal infection.
Apply calamine lotion, wear cotton clothes and use mild soaps like Dove. Also use lubrication during intercourse or masturbation and apply plain Vaseline after bath. If the symptoms persist you can add 1% hydrocortisone to the regimen.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
You think that the fungus would return to the exact same areas after all these years. Also, can you explain why we pay $15 for a question to be asked in an expert forum for no response ?
Sounds like you need an antifungal cream like Lotrimin. Use as directed. When finished, moisturize the area regularly with 100% aloe vera gel (clear kind).