<P> Some systemic disorders are involved in angular cheilitis by virtue of their association with malabsorption and the creation of nutritional deficiencies described above . Such examples include people with anorexia nervosa . Other disorders may cause lip enlargement (e.g. orofacial granulomatosis), which alters the local anatomy and extenuates the skin folds at the corners of the mouth . More still may be involved because they affect the immune system, allowing normally harmless organisms like Candida to become pathogenic and cause an infection . Xerostomia (dry mouth) is thought to account for about 5% of cases of AC . Xerostomia itself has many possible causes, but commonly the cause may be side effects of medications, or conditions such as Sjögren's syndrome . Conversely, conditions which cause drooling or sialorrhoea (excessive salivation) can cause angular cheilitis by creating a constant wet environment in the corners of the mouth . About 25% of people with Down syndrome appear to have AC . This is due to relative macroglossia, an apparently large tongue in a small mouth, which may constantly stick out of the mouth causing maceration of the corners of the mouth with saliva . Inflammatory bowel diseases (such as Crohn's disease or ulcerative colitis) can be associated with angular cheilitis . In Crohn's, it is likely the result of malabsorption and immunosuppressive therapy which gives rise to the sores at the corner of the mouth . Glucagonomas are rare pancreatic endocrine tumors which secrete glucagon, and cause a syndrome of dermatitis, glucose intolerance, weight loss and anemia . AC is a common feature of glucagonoma syndrome . Infrequently, angular cheilitis may be one of the manifestations of chronic mucocutaneous candidiasis, and sometimes cases of oropharyngeal or esophageal candidiasis may accompany angular cheilitis . Angular cheilitis may be present in human immunodeficiency virus infection, neutropenia, or diabetes . Angular cheilitis is more common in people with eczema because their skin is more sensitive to irritants . Other conditions possibly associated include plasma cell gingivitis, Melkersson - Rosenthal syndrome, or sideropenic dysphagia (also called Plummer - Vinson syndrome or Paterson - Brown - Kelly syndrome). </P> <P> Several drugs may cause AC as a side effect, by various mechanisms, such as creating drug - induced xerostomia . Various examples include isotretinoin, indinavir, and sorafenib . Isotretinoin (Accutane), an analog of vitamin A, is a medication which dries the skin . Less commonly, angular cheilitis is associated with primary hypervitaminosis A, which can occur when large amounts of liver (including cod liver oil and other fish oils) are regularly consumed or as a result from an excess intake of vitamin A in the form of vitamin supplements . Recreational drug users may develop AC . Examples include cocaine, methamphetamines, heroin, and hallucinogens . </P> <P> Allergic reactions may account for about 25--34% of cases of generalized cheilitis (i.e., inflammation not confined to the angles of the mouth). It is unknown how frequently allergic reactions are responsible for cases of angular cheilitis, but any substance capable of causing generalized allergic cheilitis may present involving the corners of the mouth alone . </P> <P> Examples of potential allergens include substances that may be present in some types of lipstick, toothpaste, acne products, cosmetics, chewing gum, mouthwash, foods, dental appliances, and materials from dentures or mercury containing amalgam fillings . It is usually impossible to tell the difference between irritant contact dermatitis and allergic contact dermatitis without a patch test . </P>

Is angular cheilitis the same as a cold sore