Angular Cheilitis (also spelled Angular Chelitis and also called Angular Stomatitis) is an inflamed lesion at the corner of the mouth. It often occurs in both corners of the mouth. In severe cases of Angular Cheilitis the lesions can bleed when the mouth is opened, and in some cases ulcers may form.

Although the root cause is unknown, Angular Cheilitis is a fungal infection that has been linked to nutritional deficiencies. Specifically, deficiencies in iron, riboflavin, zinc, or vitamin B-2. Angular Cheilitis is frequently seen in the elderly population who experience a loss of vertical dimension due to tooth loss, leading to an over closure of the mouth. Many people with dentures develop Angular Cheilitis because the angular alignment of the false teeth may not fit properly. This can lead to the mouth closing further than it should, creating small folds of skin in the corners of the mouth. These pockets of skin can become damp with saliva which can be the perfect environment for fungal bacteria to form.

The Angular Cheilitis fungal infection is caused by the same fungus that causes a yeast infection (Candida). Your doctor can test a culture of the affected area to see if you have the bacteria present. Your doctor may also do a blood test to see if you have an immune system deficiency.

Because it is a fungal infection, Angular Cheilitis should not be treated with lip balms or petroleum jellies, as these will increase the moisture levels and possibly cause the infection to spread. More appropriate treatments would include over the counter creams with antifungal and antibacterial properties.