The first sign of a skin yeast infection is itchy, red skin area around the anal area for men, and in addition, in and around the reproductive area for women. Yeast infections, including skin yeast infections, begin within the digestive and reproductive tracts of the body and then spread outside the body from the endings of the digestive and reproductive tracts. Another sign of a yeast infection is a white coating on the tongue. Tea tree oil was helpful earlier on because tea tree oil has antifungal/anti-yeast properties. Tea tree oil won't help for very long, however, if the yeast continues to grow and entrenches itself within the body. Hopefully, your wife's OB/GYN will be better at diagnosing a yeast infection than your doctors may have been. In addition to Difulcan and Nystatin, a topical antifungal that is effective against skin yeast is Clotrimazole and Betamethasone Dipropionate. Best wishes for your continued health and the continued health of your wife.