While many conditions may cause irritation in the armpits, WebMD notes that intertrigo usually causes a burning sensation along with redness and itching. When a person has intertrigo, the moist, warm skin becomes irritated and often mildly infected. A rash also typically appears between the folds of the skin.
Intertrigo most commonly occurs on the larger skin-folding areas of the body, including the abdomen, armpits, beneath the breasts and genital area. It usually appears in any skin folds that rub together and trap moisture, which includes in between the toes, in the inner thighs, in the crease of the neck or in between the buttocks. For instance, WebMD states that intertrigo often shows up as diaper rash in infants. Symptoms of intertrigo include cracked or crusty skin, foul odor, a red or reddish-brown rash and raw, itchy or oozing skin. Friction between folds of the skin, heat, lack of air circulation and moisture may not only cause intertrigo but may also worsen the condition. WebMD also notes that sweat, urine and feces also contribute to the skin problem. Intertrigo often appears in conjuntion with other infections, such as bacteria, yeast and other types of fungi, and skin diseases, such as psoriasis, may prompt the development of intertrigo.