Ringworm and yeast are two common fungi that infect the skin, according to WebMD and Dr. Heather Brannon for About.com. Both of these fungi occur on multiple body surfaces, including the stomach.
Ringworm, or tinea corporis, is a fungus that takes on a raised, circular, worm-like appearance, explains WebMD. The skin around the affected area may also appear scaly. Multiple sores or no sores at all are both possible. Ringworm spreads through contact, either with affected animals or people, or with infected surfaces. Warmth and moisture enhance the spread of ringworm. Ringworm is not usually harmful and is easily treated with over-the-counter antifungal medicines.
The fungus Candida albicans causes intertrigo, a yeast infection of skin folds, reports Brannon. The groin and armpits are the most commonly affected areas, but areas of the torso beneath the breasts or folds of stomach fat are also optimal breeding grounds for Candida albicans. This fungus naturally inhabits the skin, but excess heat and moisture, tight clothing, poor hygiene and existing skin conditions can cause it to overpopulate and cause infection. A red, wet rash is the primary symptom of intertrigo, but a doctor can also diagnose the infection via cultures. Intertrigo responds well to antifungal medication, provided the affected area is kept dry. A reduction of skin-on-skin contact and good hygiene are key to preventing intertrigo.