Angular Cheilitis: Cracked Corners of the Mouth

Table of Contents

1. What It Looks Like and Who Gets It
2. Saliva and Lip-Licking
3. Dentures and Bite Height
4. Candida and Staphylococcus aureus in Cultures
5. Riboflavin, Iron, B12, Folate, B6 and Zinc
6. How Often a Deficiency Is Actually Found
7. Diabetes, Immune Disease and Bowel Disease
8. Isotretinoin and Other Retinoid Drugs
9. Other Drugs and Face Masks
10. Whole-Food Sources of These Nutrients
11. Treatment Trials and What Is Reported
12. Recurrence: Eighty Percent in One Follow-Up
13. When the Same Spot Is Another Disease
14. Cheap Home Measures People Report
15. What Is Not Known
16. Key Research Papers
17. Connections
18. Featured Videos

What It Looks Like and Who Gets It

A 2020 review in Oral Diseases describes redness, cracks, ulcers and crusting of one or both corners of the lips and the skin next to them, with unpleasant, painful discomfort. A 2024 review in Wiener Medizinische Wochenschrift reports two age peaks, one in childhood and one in adulthood, with the condition becoming more frequent with age. The same review calls it a possible sign of an underlying disease.

The shape of the crack differs by mouth. In a 1986 study of 64 patients, people with their own teeth most often had a crack at the corner that reached the nearby skin, while denture wearers often had a deep crack running along the fold beside the lips. In 36 Southern Chinese adults, 32 had both corners affected and 4 had one. In that study 65% of the lesions were mild and 35% moderate. A Sri Lankan group of 49 adults had lesions that had lasted anywhere from 1 month to more than 4 years.

Measured rates depend almost entirely on who is examined:

• General adults: 2.9% of 308 adults over 30 in Oviedo, Spain.
• Older people in the community: 2.9% of 889 people over 65 in Santiago, Chile.
• Older denture wearers: 34% of 84 denture wearers from geriatric residences and day care centers, where it was the most common denture-related lesion. In 500 older Thai dental patients it ranked third among denture-related problems, at 4.8%.
• Braces: 11% of 660 patients in orthodontic treatment in Scotland and Greece. Good oral hygiene went with a lower rate.
• Down syndrome: about one quarter of 77 patients.
• People misusing alcohol: 3.0% of 693 in south London.
• Food-dependent adolescents: 26.8% of 369 Bhutanese refugees in Nepal.
• Rural schoolboys: 41.3% near Hyderabad, India, in a 1979 study.
• After a mouth held open in surgery: 44% of children on the first day after adenotonsillectomy in the group given no preventive ointment, falling to 10% at one week.

Saliva and Lip-Licking

Almost every review names saliva at the corners as a driver. The direct evidence is thinner than that suggests. In a 2023 study of 130 people with cheilitis of any kind, self-reported saliva at the corners of the mouth was significantly linked to angular cheilitis. Lip licking and biting, however, was linked to a different form, exfoliative cheilitis (peeling lips), and not to the corners. Angular and exfoliative cheilitis each made up only 7.7% of that group, so the numbers behind the link are small.

The proposed mechanism is simple: skin that is repeatedly wetted and then dries breaks down. A 2026 narrative review in Nutrients describes a moist, softened environment that favours microbial overgrowth, especially in older adults with dry mouth, a lowered bite and denture sore mouth. A report on health care workers in masks describes a wet-dry cycle from repeatedly putting saliva on the lips. A 1988 study of treatment supports the anatomy side of this: older age, dry skin and extended skin folds at the corner were closely tied to slower healing.

The page on dry mouth has the figures on saliva loss itself. At the other extreme is persistent drooling in older people, which a 2007 case report ties to long-lasting angular cheilitis. Surgery offers a short natural experiment: a 1999 study of 60 tonsillectomy patients found that the cracks were tied to the use of diathermy (odds ratio 3.5, with a confidence interval of 0.99 to 12.4 that just crosses no effect), in operations where the mouth is held open by instruments.

Dentures and Bite Height

The best single study on this is a 2014 analysis of 84 older denture wearers. After adjusting for other factors, angular cheilitis was tied to age, having no natural teeth at all, Candida in the mouth, an unstable denture and a reduced occlusal vertical dimension. That last term means the height between the jaws when the teeth or dentures meet. When that height falls, the jaws close further than they used to and the corners of the mouth fold in on themselves.

National data point the same way in broad terms. The U.S. Third National Health and Nutrition Examination Survey examined 17,235 people. Removable denture wearers had 3.57 times the odds of having an oral lesion of some kind, although that figure is not specific to the corners. Dentures are clearly not the whole story, though: in the Sri Lankan study only 5 of 49 patients wore full dentures.

Yeast under the denture is often assumed to feed the corners. A follow-up of 48 patients found that denture sore mouth (denture stomatitis) was not linked to how often the cracks returned. The section on thrush under dentures covers that infection itself.

Candida and Staphylococcus aureus in Cultures

These are the results of swabbing the cracks directly. The range is wide, and it depends on the group and the laboratory method:

• 64 patients, 1986: disease-causing organisms grew from all 64. Candida albicans grew in 45 and Staphylococcus aureus in 40, so many had both.
• 49 Sri Lankan adults, 1991: organisms grew from 59% of lesions. Candida grew in 24 patients and Staphylococcus aureus in 11.
• 36 Southern Chinese adults, 1995: organisms grew from 37 of 68 lesions (54%). Candida alone grew in 9, Staphylococcus aureus alone in 9 and both in 11. Among 28 people with no lesions, Candida was found in only one.
• 40 Indian patients, 2017: organisms grew in 33 (82.5%). Of those 33, Staphylococcus aureus grew in 25, Candida in 16 and streptococci in 5.
• Glasgow laboratory records, 1998 to 2000: angular cheilitis was the condition most often reported (22%) for mouth samples growing methicillin-sensitive Staphylococcus aureus. The rate of this organism rose with age, especially over 70.

Older antibiotic testing gives a sense of what this bacterium resists. Of strains from 360 patients in a 1984 report, 24% were sensitive to penicillin G, 74% to tetracycline, 93% to fusidic acid and 96% to erythromycin. Those figures are four decades old.

Finding an organism in a crack does not show that it started the crack. The authors of the Down syndrome study, who found Candida albicans more often in lip lesions than in people without them, wrote plainly that it is uncertain whether this is cause or effect. The strongest evidence that microbes matter is a small placebo-controlled comparison described under treatment.

Riboflavin, Iron, B12, Folate, B6 and Zinc

Each of these deficiencies is reported to cause cracked corners. The site's pages on riboflavin and cracked lips, vitamin B6 and folate explain the biology. What follows here is the measured data.

Riboflavin (vitamin B2)

A 2023 Annual Review of Nutrition article states that severe riboflavin deficiency is largely confined to low-income countries, where it appears as cheilosis, angular stomatitis, a sore tongue and other signs. Milder deficiency may be far more widespread and usually goes unmeasured. The field data pull in different directions:

• Bhutanese refugees, 2002: reported cases rose 6-fold, from 5.5 to 35.6 per 1,000 per month, after a fortified cereal was removed from rations. In the later survey, 85.8% had low riboflavin. Those with cracked corners had significantly lower levels, with an adjusted odds ratio of 5.1 (95% confidence interval 1.55 to 16.5).
• Southern China, 1984: adolescents averaged 0.45 mg of riboflavin a day. Cracked corners were seen in 5.8% of boys and 2.7% of girls. On 15 mg a day, scrotal skin signs cleared in three to six days, while the tongue and lip signs improved more slowly.
• Karamoja, Uganda, 2009 to 2010: only 399 of 179,172 people screened (0.2%) had cracked corners. Yet in small blood samples (58 people with symptoms and 18 without), deficiency was confirmed in 84.5% and 94.4%. In those samples deficiency was nearly universal, while the sign was rare in the screened population.
• Hyderabad schoolboys, 1979: almost all had riboflavin deficiency and 61% had pyridoxine deficiency. A month of B-complex vitamins (4 mg riboflavin and 10 mg pyridoxine a day) reduced sore tongue but had no effect on angular stomatitis, which responded to gentian violet painted on the skin. The authors concluded that the cracks had a more complex cause, perhaps linked to infection.
• Chennai school meals, 2009: in a school given iron (28 mg) and riboflavin (1 mg) in its meals on 100 days, cracked corners fell from 21% to 0%. In the comparison school with no added nutrients, they went from 23% to 20%. The children were not randomized, and the two nutrients were given together.

Iron

In 64 patients with sore mouths who proved to be iron deficient, 63% had angular cheilitis and 85% had Candida infection. Importantly, 22% were not anemic, so a normal hemoglobin did not rule the deficiency out. All the mouth changes improved on iron, plus antifungals where candidiasis was present. Two of the 64 were found to have colorectal cancer, and the authors state that finding the source of iron deficiency anemia is necessary because it may be the first sign of a more serious disease. In 37 geriatric patients, those with mouth disease had significantly lower serum iron. In the Sri Lankan group, 18 of 49 had low hemoglobin, 8 of them with the small, pale red cells typical of iron deficiency. On the other side, a 1986 study that tested serum iron and transferrin in 23 of its 64 patients ranked the other suggested causes as of subordinate importance compared with organisms. The pages on iron deficiency anemia and iron deficiency cover the wider picture.

Vitamin B12

A 2026 narrative review reports that vitamin B12 deficiency may appear with sore tongue, burning mouth and angular cheilitis even without anemia. Case data support the overlap more than they measure it. In 22 patients with vitamin B12 deficiency, the main complaint in all of them was a sore tongue, 7 had a normal-looking mouth lining, and most responded to antifungals plus vitamin B12. That abstract does not give a figure for angular cheilitis. In 43 Indian infants with the deficiency, 3 had cheilitis, and the mouth changes cleared within 3 to 4 weeks of treatment. A separate case report lists angular cheilitis among the oral signs of anemia from a dietary shortage of this vitamin. See vitamin B12 and the sore tongue and atrophic glossitis.

Folate

A letter titled “Folic-acid deficiency as a cause of angular cheilosis” appeared in The Lancet in 1971, and the 2026 review lists folate with iron and the B vitamins as linked to the condition. Studies rarely separate folate from vitamin B12, as the study in the next section shows.

Vitamin B6

The 1979 Hyderabad trial above included pyridoxine and saw no effect on the cracks. A 1975 study of 66 Aboriginal Australians found a marked decrease in angular stomatitis after fortified flour became available, alongside biochemical improvement in vitamins B1 and B6, without a control group. A 2019 report describes a woman 6 years after gastric bypass with critically low zinc and vitamin B6, a severe rash, angular cheilitis and a sore tongue. Her rash slowly improved over two weeks of replacement.

Zinc

Zinc is often listed, and direct data are scarce. That same 2019 gastric bypass case is the clearest report. In the geriatric study, plasma zinc did not differ between people with and without mouth disease, though 58% of the whole group tended to be below the reference range. The 2026 review's table of nutrients tied to angular cheilitis lists iron, folate, B vitamins and protein-energy malnutrition, and leaves out zinc. The site's zinc deficiency page covers its better-documented signs. Biotin also turns up: in a study of long-term intravenous feeding, three patients developed biotin deficiency with dry eyes and angular cheilitis or hair loss.

How Often a Deficiency Is Actually Found

This is the number most people want, and no large study answers it cleanly. The studies below tested people with this sign or a mix of similar signs, and their results differ widely:

• One dental practice, 11 years: 250 patients with burning mouth, angular cheilitis, mouth ulcers, a smooth tongue or a red mouth lining. A deficiency was found in 47.6%: iron in 24.8%, vitamin B12 or folate in 17.6%, and both in 5.2%. Most patients were women, and being female was the only predictor, and only for iron. The figures are not broken down by sign, so they do not show the rate for cracked corners alone.
• 130 people with cheilitis of all types, 2023: folate, vitamin B12 and iron were mostly within the normal range. Angular cheilitis was only part of this group, and the abstract gives no separate figure for it.
• Children, 2022: 152 children with mouth lesions and 65 healthy children had a broad panel of vitamins and zinc measured. Blood micronutrients showed no link with angular cheilitis, although they did show links with mouth ulcers and other lip disease.
• Sri Lankan adults, 1991: 18 of 49 had low hemoglobin (37%).

Two more findings narrow the picture. Blood tests can miss what the mouth shows: in the series of 64 iron-deficient patients, 22% of iron-deficient patients were not anemic. And in a smaller set of 30 people whose sore mouths led to a diagnosis (12 iron deficiency, 8 pernicious anemia, 2 both, and 8 anemia of chronic disease), none had general symptoms advanced enough to raise suspicion of anemia beforehand. Taken together, a deficiency is common in clinic groups with several mouth signs, and it is much less consistently found in people with cracked corners on their own.

Diabetes, Immune Disease and Bowel Disease

Diabetes

Among 391 people with type 2 diabetes and 391 without, angular cheilitis was significantly more common with diabetes (P = 0.006), and poor blood sugar control went with more mouth lesions overall. In type 1 diabetes, 15.1% of 405 patients had visible candidiasis of some kind, including angular cheilitis, compared with 3.0% of 268 controls. Smoking, dentures and higher long-term blood sugar were each tied to Candida threads in smears.

Human immunodeficiency virus (HIV) and other immune conditions

The textbook link with human immunodeficiency virus is less solid than it sounds. In the Women's Interagency HIV Study, with 577 women who had the virus and 152 who did not, 3% had angular cheilitis. Having the virus was linked to the other forms of oral candidiasis, but not to this one. In 1,566 patients in Yunnan, China, the rate was 4.9%. Researchers in South India did find that the organisms differ: Candida albicans and Staphylococcus aureus were more common in the cracks of people with the virus, and more common again with CD4 counts under 200. Immune drugs and related diseases also appear. Among people with oral candidiasis in a study of Sjögren's syndrome, 24% had angular cheilitis. Among 14 patients on interferon for hepatitis C, 3 had it.

Inflammatory bowel disease and celiac disease

In 198 Italian outpatients, angular cheilitis was found in 7.8% with Crohn's disease, 5% with ulcerative colitis and none of 89 controls. Disease activity did not track with it. In 62 adults with active Crohn's disease, the rate was 29.1%, and oral lesions as a whole tracked with lower hemoglobin and higher inflammation. A 2021 study of children at the time of bowel disease diagnosis found it to be the most frequent lesion in ulcerative colitis, at 12.5%. A systematic review of children with Crohn's disease reports that mouth signs may come before bowel inflammation or arrive with it, and a 2011 letter describes angular cheilitis as the first sign of Crohn's disease in two children. A 2025 systematic review of children with celiac disease also lists it among reported findings.

Plummer-Vinson syndrome

Cracked corners can be part of this rare combination of swallowing trouble, iron deficiency anemia and webs in the esophagus. The syndrome carries an increased risk of squamous cell cancer of the pharynx and esophagus.

Isotretinoin and Other Retinoid Drugs

Cheilitis, meaning the whole lip and not just the corners, is the most reliable side effect of this drug group. One caution on reading these figures: most of them count dry, inflamed lips in general. The corners are only part of it.

• 1,743 patients on isotretinoin: 78% had cheilitis. The rate depended on dose, from 47% under 0.25 mg per kg a day to 96% above 0.75 mg per kg a day. Cheilitis was involved in 22 of the 24 patients who stopped the drug because of side effects.
• 60 patients followed prospectively, 2026: 75% had cheilitis and 50% had dry mouth.
• U.S. Food and Drug Administration reports, 2004 to 2025: among 5,007 cheilitis reports, isotretinoin was the most frequently named drug, with a reporting odds ratio of 42.61. Reports of this type show a signal; they do not give a rate.
• Acitretin: a 1989 psoriasis study reported cheilitis among the most frequent side effects at 25 mg a day or more.

Researchers have built a grading scale for isotretinoin cheilitis that scores inflammation of the corners as one of four features. Not all of the lip trouble comes from the drug, though: in 400 acne patients with no previous use of oral retinoids, 34% already had cheilitis.

Trials of ways to reduce it are few. Two randomized trials, of 118 and 60 patients, reported less cheilitis with oral omega-3, given at 1 g a day in the larger one, where the difference appeared at weeks 4, 8 and 12. A trial of 82 patients found that vitamin E at 800 IU a day made no difference. A randomized pilot of 90 patients reported more improvement at 6 weeks with trichloroacetic acid 33% than with petroleum jelly.

Other Drugs and Face Masks

The Food and Drug Administration analysis above named thirty-eight drugs with significant associations. Crisaborole, a topical eczema drug, had the strongest signal. Other measured or reported drug links include:

• Immune checkpoint inhibitors for cancer: a pooled rate of 2% (95% confidence interval 0 to 4%) across trials, with the authors noting poor and inconsistent reporting.
• Selumetinib: 1 of 11 patients in a skin side-effect review.
• Single case reports: published letters describe angular cheilitis after paroxetine, after atomoxetine and repeatedly after secukinumab injections. A single report cannot establish that the drug was the cause.

Masks entered this literature during the pandemic. A 2020 letter describes 33 health care workers who complained of lip symptoms after wearing masks for a mean of 8.92 hours a day. Twelve (36.36%) had angular cheilitis, and secondary infection was seen in 27.27%. These were people who came forward with symptoms, so that figure does not show how common this is among mask wearers overall. In a separate measured study, 21 healthy people wore masks for 6 hours, and skin temperature, redness, hydration and oil all changed. The authors reported that the area around the mouth could be the most affected. A wet, warm, enclosed corner fits the saliva explanation above, though no study has tested that directly.

Whole-Food Sources of These Nutrients

These figures come from U.S. Department of Agriculture FoodData Central (SR Legacy records) and are per 100 grams. The foods are widely available, and many of them are low in cost. Full ranked lists are on the site's food-source pages for riboflavin, iron, vitamin B12, folate, vitamin B6 and zinc.

Rice shows how much milling removes. Cooked unenriched white rice has 0.013 mg of riboflavin, 0.2 mg of iron, 3 mcg of folate and 0.49 mg of zinc per 100 grams, against the brown rice figures above. Enrichment adds back iron and folate to white rice, but not the riboflavin or zinc in these records. Vitamin B12 in these foods comes from animal sources; the plant foods in the table contain essentially none, and natto is listed at zero. Beef liver is also very high in vitamin A, and the site's page on vitamin A toxicity covers that hazard. Among fermented soy foods, natto stands out at 8.6 mg of iron per 100 grams. The site's food section covers these foods further.

Treatment Trials and What Is Reported

The 2020 review states the problem directly: antifungals are the first choice of most clinicians, yet very limited evidence supports them, with just two randomized trials published in the 1970s and 1980s. Most other options rest on case reports or small case series.

Antifungal and antibacterial ointments

The key study is from 1988. In an open trial, 50 patients with Candida albicans, Staphylococcus aureus or both received nystatin and/or fusidic acid ointment chosen by culture result, and 96% had no sign of infection after 42 days. In a double-blind comparison on 8 patients with Candida on both sides, each patient served as their own control: the nystatin side healed by 28 days, and the placebo side persisted throughout. Eight people is a very small trial, and it remains close to the best evidence the searches for this page could find. In a separate group of 9 people with long-lasting lip erosions other than the corners, 7 grew Candida, and 6 had already failed topical steroids. On miconazole gel for about 2 weeks, 5 cleared, 2 clearly improved and 2 did not respond. The searches for this page found no modern randomized trial comparing antifungal, antibacterial and steroid ointments head to head.

Mild steroid combinations

The authors of the 2020 review report that in their clinical experience the most consistent result came from a combination of 1% isoconazole and 0.1% diflucortolone valerate ointment. This is their own experience and they call for larger trials to test it. Steroid use around the mouth has its own known hazard, which the page on perioral dermatitis describes.

Barrier and moisturising ointments

The clearest trial is about prevention. In 101 children having adenotonsillectomy, one application of dexpanthenol to the corners before surgery cut first-day cracks from 44% to 9.8% (odds ratio 0.14, 95% confidence interval 0.05 to 0.41). At one week the difference (3.9% against 10%) was no longer significant, and pain did not differ. As treatment, an oxygen-enriched oil gel used three times daily for 10 days was tested in 30 patients with no control group, and pain, lesion size and germ counts fell. The health care workers in masks were managed with plain emollients plus other drugs as needed, with no measured comparison.

Denture adjustment

Restoring bite height rests on the 2014 risk-factor study above. The 2020 review says the methods used for it have mostly been reported in case reports or series. A 2007 case report describes building a saliva channel into a denture for a person with chronic drooling. The searches for this page found no controlled trial.

Vitamins and minerals

In the 2020 review, B-vitamin supplementation is among the options mostly backed by small reports. Iron with antifungals improved the mouth changes in the series of 64 iron-deficient patients, but with no control group. The 1979 Hyderabad B-complex trial found no effect on the cracks, while gentian violet worked. The Chennai school meal study saw them disappear on a mix of iron and riboflavin. The two results do not agree, and only the Chennai children received iron.

Fillers and light therapy

Fillers aim to lift the fold itself. A 2018 case report describes complete remission with hyaluronic acid filler in an 80-year-old whose recurrent cracks had not resolved with conventional care, and an Indian dermatology guideline lists angular cheilitis as a filler indication. Photodynamic therapy, in which a light-activated dye is applied to the crack, healed 9 of 10 patients with stubborn or recurring cases in a 2025 pilot, one with a recurrence after a month. In 13 critically ill patients in a 2026 study, the cure rate was 61.5%, while 92.3% were also on antifungal drugs. Neither study had a control group.

Recurrence: Eighty Percent in One Follow-Up

The single most important long-term figure comes from a 1988 study of 48 patients who had been successfully treated with antimicrobial ointment and were checked at 8 months and 5 years. Eighty percent reported at least one recurrence. People with dry-skin conditions or white patches inside the mouth (leukoplakia) had more. Neither denture sore mouth nor which organism had been found at the start predicted it. The authors concluded that the benefit of antimicrobial treatment was short-lasting and that the condition needed to be seen in a longer perspective. This fits a model in which the ointment clears the germs and leaves the fold, the bite and the skin as they were. The searches for this page found no later study repeating this follow-up.

When the Same Spot Is Another Disease

Most cracked corners are benign, but the location is shared with conditions that have a very different outlook. These are the findings as published.

Squamous cell cancer

Lip cancer can start at the corner of the mouth: one surgical report gives the corner as the origin in 6% to 8.5% of lip cancers. A 1996 case report describes long-lasting angular cheilitis, with Candida albicans repeatedly isolated, that developed into carcinoma. It is a single case, and it does not show how often this happens. White patches also matter here: in Sri Lanka, leukoplakia at the corner of the mouth was linked to an infective cause of the cracks, and a separate study found Candida in 47% of oral leukoplakia, with angular cheilitis significantly tied to the Candida-infected form. Leukoplakia is a recognised precancerous lesion. Plummer-Vinson syndrome, covered above, adds a further link through long-standing iron deficiency; a 2025 systematic review of 7 case reports found head and neck cancers in such patients, including younger ones.

Clinicians treat these features at the corner of the mouth as signs of possible cancer: a sore that keeps enlarging, a firm or raised edge, a lasting white or red patch that does not wipe off, bleeding without reason, or a lesion on one side that does not heal. The site's oral cancer page lists an ulcer lasting more than two weeks in an adult as the leading warning sign, and a biopsy is the only way to tell these apart. Long-term sun damage to the lip is a further route, described under actinic keratosis and squamous cell carcinoma.

Syphilis

Secondary syphilis can produce a split papule at the corner of the mouth, known as false angular cheilitis or fausse perlèche. In a 2009 to 2019 series from Argentina, it appeared in 8 of 58 patients (13%) with oral secondary syphilis. All 8 were young women, average age about 25, and the lesions were painful fissured papules, on one side only, along with other mouth lesions and swollen glands under the jaw. A 2017 case report in a man with human immunodeficiency virus describes the same split papule plus a sore tongue, with no skin rash at all. A syphilis blood test (VDRL) gave a titer of 1/128, and the lesions cleared on penicillin. An ordinary cream does not treat syphilis, and syphilis lesions are contagious, so this mimic carries consequences well beyond the skin.

Other look-alikes

A 2018 review groups cheilitis into mainly reversible forms, including angular and contact, and mainly irreversible forms such as actinic and granulomatous. Others are contact allergy, impetigo, cold sores, and oral thrush spreading from inside the mouth.

Cheap Home Measures People Report

These come from what people describe in everyday use and from general clinical habit. They are reports, not trial results.

• Petroleum jelly or a plain, unflavoured lip ointment on the corners, especially at bedtime. People say it keeps saliva off the skin during sleep.
• Drying the corners with a clean tissue after eating or after waking, and trying to break a lip-licking habit.
• Taking dentures out overnight and cleaning them daily, which many denture wearers link with fewer flare-ups.
• Coconut oil, olive oil or honey dabbed on the cracks. These are popular home remedies.
• Changing toothpaste or lip products, for those who notice flare-ups after a flavoured or new product.
• Changing a damp mask more often, for long days in one.
• Eating more eggs, liver, sardines, beans and fermented soy, for those who suspect a poor diet is behind it.

What Is Not Known

• How much each cause contributes. No study has measured saliva, dentures, organisms, deficiency and drugs together in the same large group of people with cracked corners.
• Whether organisms start the cracks or settle in afterwards. The small placebo comparison shows that nystatin helped Candida-infected cracks heal in 8 people; it does not show that the yeast began the process.
• The true deficiency rate. The largest clinic figure (47.6%) mixes five different mouth signs, and riboflavin markers are rarely measured at all.
• Why deficiency alone so often fails to produce the sign. In Uganda nearly everyone tested was deficient, and 0.2% of those screened had cracks.
• The best treatment. There is no modern head-to-head trial of the common ointments, and none of denture correction or fillers.
• Whether anything reduces recurrence. The one long-term follow-up is from 1988, and no study has tested a way of preventing relapse over years.
• How often a chronic crack turns out to be cancer. The available evidence is case reports. No cohort has been followed for it.
• The real effect of masks. The figures come from a self-selected group of 33 and short skin measurements.
• The home measures above. None has been tested in angular cheilitis; the searches for this page found no such trial.

Key Research Papers

1. Chiriac A, Chiriac AE, Pinteala T, Spinei A, Savin L, Zelenkova H, Wollina U. Angular cheilitis-an oral disease with many facets. Wien Med Wochenschr. 2024;174(15-16):315-322. PubMed PMID: 38517608
2. Cabras M, Gambino A, Broccoletti R, Lodi G, Arduino PG. Treatment of angular cheilitis: A narrative review and authors' clinical experience. Oral Dis. 2020;26(6):1107-1115. PubMed PMID: 31464357
3. McNulty H, Pentieva K, Ward M. Causes and Clinical Sequelae of Riboflavin Deficiency. Annu Rev Nutr. 2023;43:101-122. PubMed PMID: 37603429
4. Ohman SC, Dahlén G, Möller A, Ohman A. Angular cheilitis: a clinical and microbial study. J Oral Pathol. 1986;15(4):213-7. PubMed PMID: 3088236
5. Oza N, Doshi JJ. Angular cheilitis: A clinical and microbial study. Indian J Dent Res. 2017;28(6):661-665. PubMed PMID: 29256466
6. Dias AP, Samaranayake LP. Clinical, microbiological and ultrastructural features of angular cheilitis lesions in Southern Chinese. Oral Dis. 1995;1(1):43-8. PubMed PMID: 7553380
7. Warnakulasuriya KA, Samaranayake LP, Peiris JS. Angular cheilitis in a group of Sri Lankan adults: a clinical and microbiologic study. J Oral Pathol Med. 1991;20(4):172-5. PubMed PMID: 2061855
8. Ohman SC, Jontell M. Treatment of angular cheilitis. The significance of microbial analysis, antimicrobial treatment, and interfering factors. Acta Odontol Scand. 1988;46(5):267-72. PubMed PMID: 3063051
9. Ohman SC, Jontell M, Dahlen G. Recurrence of angular cheilitis. Scand J Dent Res. 1988;96(4):360-5. PubMed PMID: 3166200
10. Cross D, Eide ML, Kotinas A. The clinical features of angular cheilitis occurring during orthodontic treatment: a multi-centre observational study. J Orthod. 2010;37(2):80-6. PubMed PMID: 20567030
11. Scully C, van Bruggen W, Diz Dios P, Casal B, Porter S, Davison MF. Down syndrome: lip lesions (angular stomatitis and fissures) and Candida albicans. Br J Dermatol. 2002;147(1):37-40. PubMed PMID: 12100182
12. Smith AJ, Robertson D, Tang MK, Jackson MS, MacKenzie D, Bagg J. Staphylococcus aureus in the oral cavity: a three-year retrospective analysis of clinical laboratory data. Br Dent J. 2003;195(12):701-3; discussion 694. PubMed PMID: 14718964
13. MacFarlane TW, McGill JC, Samaranayake LP. Antibiotic sensitivity and phage typing of Staphylococcus aureus isolated from non-hospitalized patients with angular cheilitis. J Hosp Infect. 1984;5(4):444-6. PubMed PMID: 6085101
14. Krishnan PA, Kannan R. Comparative study on the microbiological features of angular cheilitis in HIV seropositive and HIV seronegative patients from South India. J Oral Maxillofac Pathol. 2013;17(3):346-50. PubMed PMID: 24574650
15. Espinoza I, Rojas R, Aranda W, Gamonal J. Prevalence of oral mucosal lesions in elderly people in Santiago, Chile. J Oral Pathol Med. 2003;32(10):571-5. PubMed PMID: 14632931
16. Jainkittivong A, Aneksuk V, Langlais RP. Oral mucosal conditions in elderly dental patients. Oral Dis. 2002;8(4):218-23. PubMed PMID: 12206403
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Connections

• Dermatology — the parent section
• Riboflavin Deficiency: Cracked Lips and Mouth Sores — the vitamin side of the same sign
• Iron Deficiency Anemia — causes and tests
• Oral Thrush — Candida inside the mouth, including under dentures
• Dry Mouth — saliva loss and its causes
• Atrophic Glossitis — the smooth sore tongue that often comes with it
• Oral Cancer — warning signs at the same site
• Syphilis — the split papule that imitates it

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