Skin yeast infections can occur under the arms, along the inner thigh, under the breasts, under excess fatty folds, in the crease of the buttocks, under finger nails, under toe nails, and in the webs of fingers and toes. Skin yeast infections have been linked with elevated blood cholesterol levels. Humidity, tight clothing, poor hygiene, topical steroids, and other skin diseases can contribute to skin yeast infections.