[5] Angular cheilitis is a fairly non specific term which describes the presence of an inflammatory lesion in a particular anatomic site (i.e. the corner of the mouth).

[2] Later, the usual appearance is a roughly triangular area of erythema, edema (swelling) and breakdown of skin at either corner of the mouth.

[2][4] Sometimes contributing factors can be readily seen, such as loss of lower face height from poorly made or worn dentures, which results in mandibular overclosure ("collapse of jaws").

[2][9] Angular cheilitis is thought to be a multifactorial disorder of infectious origin,[10] with many local and systemic predisposing factors.

Potassium hydroxide preparation is recommended by some to help distinguish between the harmless and the pathogenic forms, and thereby highlight which cases of angular cheilitis are truly caused by Candida.

[citation needed] A lesion caused by recurrence of a latent herpes simplex infection can occur in the corner of the mouth.

Rather than utilizing antifungal creams, angular herpes simplex is treated in the same way as a cold sore, with topical antiviral drugs such as aciclovir.

Because of the delayed onset of contact dermatitis and the recovery period lasting days to weeks, people typically do not make the connection between the causative agent and the symptoms.

[medical citation needed] Several different nutritional deficiency states of vitamins or minerals have been linked to angular cheilitis.

[5] Chronic iron deficiency may also cause koilonychia (spoon shaped deformity of the fingernails) and glossitis (inflammation of the tongue).

[5] Vitamin B2 deficiency (ariboflavinosis) may also cause AC, and other conditions such as redness of mucous membranes, magenta colored glossitis (pink inflammation of the tongue).

[5] Vitamin B5 deficiency may also cause AC, along with glossitis, and skin changes similar to seborrhoeic dermatitis around the eyes, nose and mouth.

[5] Vitamin B3 deficiency (pellagra) is another possible cause, and in which other association conditions such as dermatitis, diarrhea, dementia and glossitis can occur.

[5] Acrodermatitis enteropathica is an autosomal recessive genetic disorder causing impaired absorption of zinc, and is associated with AC.

[5] In general, these nutritional disorders may be caused by malnutrition, such as may occur in alcoholism or in poorly considered diets, or by malabsorption secondary to gastrointestinal disorders (e.g. Coeliac disease or chronic pancreatitis) or gastrointestinal surgeries (e.g. pernicious anemia caused by ileal resection in Crohn's disease).

[5] Some systemic disorders are involved in angular cheilitis by virtue of their association with malabsorption and the creation of nutritional deficiencies described above.

[5] Other disorders may cause lip enlargement (e.g. orofacial granulomatosis),[5] 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.

[9] Glucagonomas are rare pancreatic endocrine tumors which secrete glucagon, and cause a syndrome of dermatitis, glucose intolerance, weight loss and anemia.

[citation needed] 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.

[citation needed] Severe tooth wear or ill fitting dentures may cause wrinkling at the corners of the lip that creates a favorable environment for the condition.

The loss of vertical dimension has been associated with angular cheilitis in older individuals with an increase in facial laxity.

Where Candida species are involved, angular cheilitis is classed as a type of oral candidiasis, specifically a primary (group I) Candida-associated lesion.

[24] Oral candidiasis, especially denture-related stomatitis is often found to be present where there is angular cheilitis, and if it is not treated, the sores at the corners of the mouth may often recur.

Commercial preparations are marketed for this purpose, although dentures may be left in dilute (1:10 concentration) household bleach overnight, but only if they are entirely plastic and do not contain any metal parts, and with rinsing under clean water before use.

[4] Secondly, there may be a need to increase the vertical dimension of the lower face to prevent overclosure of the mouth and formation of deep skin folds.

[2][4] Other measures which seek to reverse the local factors that may be contributing to the condition include improving oral hygiene, stopping smoking or other tobacco habits and use of a barrier cream (e.g. zinc oxide paste) at night.

[14] If Staphylococcus aureus infection is demonstrated by microbiological culture to be responsible (or suspected), the treatment may be changed to fusidic acid cream,[8] an antibiotic which is effective against this type of bacteria.

Finally, if the condition appears resistant to treatment, investigations for underlying causes such as anemia or nutrient deficiencies or HIV infection.