Erythematous (atrophic) candidiasis is when the condition appears as a red, raw-looking lesion. Some sources consider denture-related stomatitis, angular stomatitis, median rhombiod glossitis, and antiobiotic-induced stomatitis as subtypes of erythematous candidiasis, since these lesions are commonly erythematous/atrophic. It may precede the formation of a pseudomembrane, be left when the membrane is removed, or arise without prior pseudomembranes. Some sources state that erythematous candidiasis accounts for 60% of oral candidiasis cases. Where it is associated with inhalation steroids (often used for treatment of asthma), erythematous candidiasis commonly appears on the palate or the dorsum of the tongue. On the tongue, there is loss of the lingual papillae (depapillation), leaving a smooth area.

Acute erythematous candidiasis usually occurs on the dorsum of the tongue in persons taking long term corticosteroids or antibiotics, but occasionally it can occur after only a few days of using a topical antibiotic. This is usually termed "antibiotic sore mouth", "antibiotic sore tongue", or "antibiotic-induced stomatitis" because it is commonly painful as well as red.

Chronic erythematous candidiasis is more usually associated with denture wearing (see denture-related stomatitis).

Acute pseudomembranous candidiasis is a classic form of oral candidiasis, commonly referred to as thrush. Overall, this is the most common type of oral candidiasis, accounting for about 35% of oral candidiasis cases.

It is characterized by a coating or individual patches of pseudomembranous white slough that can be easily wiped away to reveal erythematous (reddened), and sometimes minimally bleeding, mucosa beneath. These areas of pseudomembrane are sometimes described as "curdled milk", or "cottage cheese". The white material is made up of debris, fibrin, and desquamated epithelium that has been invaded by yeast cells and hyphae that invade to the depth of the stratum spinosum. Due to the fact that an erythematous surface is revealed beneath the pseudomembranes, some consider pseudomembranous candidiasis and erythematous candidiasis stages of the same entity. Some sources state that if there is bleeding when the pseudomembrane is removed, then the mucosa has likely been affected by an underlying process such as lichen planus or chemotherapy. Pseudomembraneous candidiasis can involve any part of the mouth, but usually it appears on the tongue, buccal mucosae or palate.

It is classically an acute condition, appearing in infants, people taking antibiotics or immunosuppressant medications, or immunocompromising diseases. However, sometimes it can be chronic and intermittent, even lasting for many years. Chronicity of this subtype generally occurs in immunocompromised states, (e.g., leukemia, HIV) or in persons who use corticosteroids topically or by aerosol. Acute and chronic pseudomembranous candidiasis are indistinguishable in appearance.

Despite the alternative name for this condition, "denture sore mouth", it is usually painless and asymptomatic. The appearance of the involved mucosa is erythematous (red) and edematous (swollen), sometimes

with petechial hemorrhage (pin-points of bleeding). This usually occurs beneath an upper denture. Sometimes angular cheilitis can coexist, which is inflammation of the corners of the mouth, also often associated with "Candida albicans". Stomatitis rarely develops under a lower denture. The affected mucosa is often sharply defined, in the shape of the covering denture.

This condition is characterized by a persistent erythematous, rhomboidal depapillated lesion in the central area of the dorsum of the tongue, just in front of the circumvallate papillae. Median rhomboid glossitis is a type of oral candidiasis, and rarely causes any symptoms. It is treated with antifungal medication. Predisposing factors include use of corticosteroid sprays or inhalers or immunosuppression.

Geographic tongue, also termed benign migratory glossitis, is a common condition which usually affects the dorsal surface of the tongue. It is characterized by patches of depapillation and erythema bordered by a whitish peripheral zone. These patches give the tongue the appearance of a map, hence the name. Unlike glossitis due to nutritional deficiencies and anemia, the lesions of geographic tongue move around the tongue over time. This is because in geographic tongue, new areas of the tongue become involved with the condition whilst previously affected areas heal, giving the appearance of a moving lesion. The cause is unknown, and there is no curative treatment. Rarely are there any symptoms associated with the lesions, but occasionally a burning sensation may be present, which is exacerbated by eating hot, spicy or acidic foodstuffs. Some consider geographic tongue to be an early stage of fissured tongue, since the two conditions often occur in combination.

Also called smoker's palatal keratosis, this condition may occur in smokers, especially pipe smokers. The palate appears dry and cracked, and white from keratosis. The minor salivary glands appear as small, red and swollen bumps. It is not a premalignant condition, and the appearance reverses if the smoking is stopped.

The Newton classification divides denture-related stomatitis into three types based on severity. Type one may represent an early stage of the condition, whilst type two is the most common and type three is uncommon.

- Type 1 - Localized inflammation or pinpoint hyperemia

- Type 2 - More diffuse erythema (redness) involving part or all of the mucosa which is covered by the denture

- Type 3 - Inflammatory nodular/papillary hyperplasia usually on the central hard palate and the alveolar ridge

The term "necrotizing ulcerative gingivostomatitis" is sometimes used as a synonym of the necrotizing periodontal disease more commonly termed necrotizing ulcerative gingivitis, or a more severe form (also termed necrotizing stomatitis). The term "necrotizing gingivostomatitis" is also sometimes used.

Aphthous stomatitis (also termed recurrent aphthous stomatits, RAS, and commonly called "canker sores") is a very common cause of oral ulceration. 10–25% of the general population suffer from this non-contagious condition. The appearance of aphthous stomatitis varies as there are 3 types, namely minor aphthous ulceration, major aphthous ulceration and herpetiform ulceration. Minor aphthous ulceration is the most common type, presenting with 1–6 small (2-4mm diameter), round/oval ulcers with a yellow-grey color and an erythematous (red) "halo". These ulcers heal with no permanent scarring in about 7–10 days. Ulcers recur at intervals of about 1–4 months. Major aphthous ulceration is less common than the minor type, but produces more severe lesions and symptoms. Major aphthous ulceration presents with larger (>1 cm diameter) ulcers that take much longer to heal (10–40 days) and may leave scarring. The minor and major subtypes of aphthous stomatitis usually produce lesions on the non-keratinized oral mucosa (i.e. the inside of the cheeks, lips, underneath the tongue and the floor of mouth), but less commonly major aphthous ulcers may occur in other parts of the mouth on keratinized mucosal surfaces. The least common type is herpetiform ulceration, so named because the condition resembles primary herpetic gingivostomatitis. Herpetiform ulcers begin as small blisters (vesicles) which break down into 2-3mm sized ulcers. Herpetiform ulcers appear in "crops" sometimes hundreds in number, which can coalesce to form larger areas of ulceration. This subtype may cause extreme pain, heals with scarring and may recur frequently.

The exact cause of aphthous stomatitis is unknown, but there may be a genetic predisposition in some people. Other possible causes include hematinic deficiency (folate, vitamin B, iron), stopping smoking, stress, menstruation, trauma, food allergies or hypersensitivity to sodium lauryl sulphate (found in many brands of toothpaste). Aphthous stomatitis has no clinically detectable signs or symptoms outside the mouth, but the recurrent ulceration can cause much discomfort to sufferers. Treatment is aimed at reducing the pain and swelling and speeding healing, and may involve systemic or topical steroids, analgesics (pain killers), antiseptics, anti-inflammatories or barrier pastes to protect the raw area(s).

Persons with aphthous stomatitis have no detectable systemic symptoms or signs (i.e., outside the mouth). Generally, symptoms may include prodromal sensations such as burning, itching, or stinging, which may precede the appearance of any lesion by some hours; and pain, which is often out of proportion to the extent of the ulceration and is worsened by physical contact, especially with certain foods and drinks (e.g., if they are acidic). Pain is worst in the days immediately following the initial formation of the ulcer, and then recedes as healing progresses. If there are lesions on the tongue, speaking and chewing can be uncomfortable, and ulcers on the soft palate, back of the throat, or esophagus can cause painful swallowing. Signs are limited to the lesions themselves.

Ulceration episodes usually occur about 3–6 times per year. However, severe disease is characterized by virtually constant ulceration (new lesions developing before old ones have healed) and may cause debilitating chronic pain and interfere with comfortable eating. In severe cases, this prevents adequate nutrient intake leading to malnutrition and weight loss.

Aphthous ulcers typically begin as erythematous macules (reddened, flat area of mucosa) which develop into ulcers that are covered with a yellow-grey fibrinous membrane that can be scraped away. A reddish "halo" surrounds the ulcer. The size, number, location, healing time, and periodicity between episodes of ulcer formation are all dependent upon the subtype of aphthous stomatitis.

Herpetiform ulcers, (also termed stomatitis herpetiformis, or herpes-like ulcerations) is a subtype of aphthous stomatitis so named because the lesions resemble a primary infection with herpes simplex virus (primary herpetic gingivostomatitis). However, herpetiform ulceration is not caused by herpes viruses. As with all types of aphthous stomatitis, it is not contagious. Unlike true herpetic ulcers, herpetiforme ulcers are not preceded by vesicles (small, fluid filled blisters). Herpetiforme ulcers are less than 1 mm in diameter and occur in variably sized crops up to one hundred at a time. Adjacent ulcers may merge to form larger, continuous areas of ulceration. Healing occurs within fifteen days without scarring. The ulceration may affect keratinized mucosal surfaces in addition to non keratinized. Herpetiform ulceration is often extremely painful, and the lesions recur more frequently than minor or major aphthous ulcers. Recurrence may be so frequent that ulceration is virtually continuous. It generally occurs in a slightly older age group than the other subtypes, and females are affected slightly more frequently than males.

As a result of radiotherapy to the mouth, radiation-induced stomatitis may develop, which can be associated with mucosal erosions and ulceration. If the salivary glands are irradiated, there may also be xerostomia (dry mouth), making the oral mucosa more vulnerable to frictional damage as the lubricating function of saliva is lost, and mucosal atrophy (thinning), which makes a breach of the epithelium more likely. Radiation to the bones of the jaws causes damage to osteocytes and impairs the blood supply. The affected hard tissues become hypovascular (reduced number of blood vessels), hypocellular (reduced number of cells), and hypoxic (low levels of oxygen). Osteoradionecrosis is the term for when such an area of irradiated bone does not heal from this damage. This usually occurs in the mandible, and causes chronic pain and surface ulceration, sometimes resulting in non-healing bone being exposed through a soft tissue defect. Prevention of osteradionecrosis is part of the reason why all teeth of questionable prognosis are removed before the start of a course of radiotherapy.

Homogenous leukoplakia (also termed "thick leukoplakia") is usually well defined white patch of uniform, flat appearance and texture, although there may be superficial irregularities. Homogenous leukoplakia is usually slightly elevated compared to surrounding mucosa, and often has a fissured, wrinkled or corrugated surface texture, with the texture generally consistent throughout the whole lesion. This term has no implications on the size of the lesion, which may be localized or extensive. When homogenous leukoplakia is palpated, it may feel leathery, dry, or like cracked mud.

Most cases of leukoplakia cause no symptoms, but infrequently there may be discomfort or pain. The exact appearance of the lesion is variable. Leukoplakia may be white, whitish yellow or grey. The size can range from a small area to much larger lesions. The most common sites affected are the buccal mucosa, the labial mucosa and the alveolar mucosa, although any mucosal surface in the mouth may be involved. The clinical appearance, including the surface texture and color, may be homogenous or non-homogenous (see: classification). Some signs are generally associated with a higher risk of cancerous changes (see: prognosis).

Leukoplakia may rarely be associated with esophageal carcinoma.

In the initial phase of the disease, the mucosa feels leathery with palpable fibrotic bands. In the advanced stage the oral mucosa loses its resiliency and becomes blanched and stiff. The disease is believed to begin in the posterior part of the oral cavity and gradually spread outward.

Other features of the disease include:

- Xerostomia

- Recurrent ulceration

- Pain in the ear or deafness

- Nasal intonation of voice

- Restriction of the movement of the soft palate

- A budlike shrunken uvula

- Thinning and stiffening of the lips

- Pigmentation of the oral mucosa

- Dryness of the mouth and burning sensation

- Decreased mouth opening and tongue protrusion

The symptoms can be mild or severe and may include:

- Not able to chew or swallow

- Sores on the inside of the cheeks or gums

- Fever

- General discomfort, uneasiness, or ill feeling

- Very sore mouth with no desire to eat

- Halitosis (bad breath)

There are many oral and maxillofacial pathologies which are not fully understood.

- Burning mouth syndrome (BMS) is a disorder where there is a burning sensation in the mouth that has no identifiable medical or dental cause. The disorder can affect anyone but tends to occur most often in middle aged women. BMS has been hypothesized to be linked to a variety of factors such as the menopause, dry mouth (xerostomia) and allergies. BMS usually lasts for several years before disappearing for unknown reasons. Other features of this disorder include anxiety, depression and social isolation. There is no cure for this disorder and treatment includes use of hydrating agents, pain medications, vitamin supplements or the usage of antidepressants.

- Aphthous stomatitis is a condition where ulcers (canker sores) appear on the inside of the mouth, lips and on tongue. Most small canker sores disappear within 10–14 days. Canker sores are most common in young and middle aged individuals. Sometimes individuals with allergies are more prone to these sores. Besides an awkward sensation, these sores can also cause pain or tingling or a burning sensation. Unlike herpes sores, canker sores are always found inside the mouth and are usually less painful. Good oral hygiene does help but sometime one may have to use a topical corticosteroid.

- Migratory stomatitis is a condition that involves the tongue and other oral mucosa. The common migratory glossitis (geographic tongue) affects the anterior two thirds of the dorsal and lateral tongue mucosa of 1% to 2.5% of the population, with one report of up to 12.7% of the population. The tongue is often fissured, especially. in elderly individuals. In the American population, a lower prevalence was reported among Mexican Americans (compared with Caucasians and African Americans) and cigarette smokers. When other oral mucosa, beside the dorsal and lateral tongue, are involved, the term migratory stomatitis (or ectopic geographic tongue) is preferred. In this condition, lesions infrequently involve also the ventral tongue and buccal or labial mucosa. They are rarely reported on the soft palate and floor of the mouth.

A great many diseases involve the mouth, jaws and orofacial skin. Some example pathologies which can involve the oral and maxillofacial region are listed. Some are more common than others, and this list is by no means complete. The examples are considered according to a surgical sieve.

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). As there are different possible causes and contributing factors from one person to the next, the appearance of the lesion is somewhat variable. The lesions are more commonly symmetrically present on both sides of the mouth, but sometimes only one side may be affected. In some cases, the lesion may be confined to the mucosa of the lips, and in other cases the lesion may extend past the vermilion border (the edge where the lining on the lips becomes the skin on the face) onto the facial skin. Initially, the corners of the mouth develop a gray-white thickening and adjacent erythema (redness). Later, the usual appearance is a roughly triangular area of erythema, edema (swelling) and breakdown of skin at either corner of the mouth. The mucosa of the lip may become fissured (cracked), crusted, ulcerated or atrophied. There is not usually any bleeding. Where the skin is involved, there may be radiating rhagades (linear fissures) from the corner of the mouth. Infrequently, the dermatitis (which may resemble eczema) can extend from the corner of the mouth to the skin of the cheek or chin. If "Staphylococcus aureus" is involved, the lesion may show golden yellow crusts. In chronic angular cheilitis, there may be suppuration (pus formation), exfoliation (scaling) and formation of granulation tissue.

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"). If there is a nutritional deficiency underlying the condition, various other signs and symptoms such as glossitis (swollen tongue) may be present. In people with angular cheilitis who wear dentures, often there may be erythematous mucosa underneath the denture (normally the upper denture), an appearance consistent with denture-related stomatitis. Typically the lesions give symptoms of soreness, pain, pruritus (itching) or burning or a raw feeling.

Cancer patients undergoing chemotherapy usually become symptomatic four to five days after beginning treatment, reaching a peak at around day 10, and then slowly improving over the course of a few weeks. Mucositis associated with radiotherapy usually appears at the end of the second week of treatment and may last for six to eight weeks.

As a result of cell death in reaction to chemo- or radio-therapy, the mucosal lining of the mouth becomes thin, may slough off and then become red, inflamed and ulcerated. The ulcers may become covered by a yellowish white fibrin clot called a pseudomembrane. Peripheral erythema is usually present. Ulcers may range from 0.5 cm to greater than 4 cm. Oral mucositis can be severely painful. The degree of pain is usually related to the extent of the tissue damage. Pain is often described as a burning sensation accompanied by reddening. Due to pain, the patient may experience trouble speaking, eating, or even opening the mouth.

Dysgeusia, or an alteration in taste perception, is common, especially for those who are receiving concomitant radiation therapy to the neck and mouth area. "Taste blindness", or an altered sense of taste, is a temporary condition that occurs because of effects on taste buds that are mostly located in the tongue. Sometimes, only partial recovery of taste occurs. Common complaints are of food tasting too sweet or too bitter or of a continuous metallic taste.

Although often the terms "erythroplasia" and "erythroplakia" are used synonymously, some sources distinguish them, stating that the latter is maccular (flat) while the former is papular (bumpy).

Erythroplakia of the genital mucosae is often referred to as erythroplasia of Queyrat.

The most common areas in the mouth where erythroplakia is found are the floor of the mouth, buccal vestibule, the tongue, and the soft palate. It appears as a red macule or plaque with well-demarcated borders. The texture is characterized as soft and velvety. An adjacent area of leukoplakia may be found along with the erythroplakia.

Erythroplasia may also occur on the laryngeal mucosa, or the anal mucosa.

Gingivostomatitis (also known as primary herpetic gingivostomatitis or orolabial herpes) is a combination of gingivitis and stomatitis, or an inflammation of the oral mucosa and gingiva. Herpetic gingivostomatitis is often the initial presentation during the first ("primary") herpes simplex infection. It is of greater severity than herpes labialis (cold sores) which is often the subsequent presentations. Primary herpetic gingivostomatitis is the most common viral infection of the mouth.

Primary herpetic gingivostomatitis (PHGS) represents the clinically apparent pattern of primary herpes simplex virus (HSV) infection, since the vast majority of other primary infections are symptomless. PHGS is caused predominantly by HSV-1 and affects mainly children. Prodromal symptoms, such as fever, anorexia, irritability, malaise and headache, may occur in advance of disease. The disease presents as numerous pin-head vesicles, which rupture rapidly to form painful irregular ulcerations covered by yellow–grey membranes. Sub-mandibular lymphadenitis, halitosis and refusal to drink are usual concomitant findings.

22% of cases of angular cheilitis are due to irritants. Saliva contains digestive enzymes, which may have a degree of digestive action on tissues if they are left in contact. The corner of the mouth is normally exposed to saliva more than any other part of the lips. Reduced lower facial height (vertical dimension or facial support) is usually caused by edentulism (tooth loss), or wearing worn down, old dentures or ones which are not designed optimally. This results in overclosure of the mandible (collapse of the jaws), which extenuates the angular

skin folds at the corners of the mouth, in effect creating an intertriginous skin crease. The tendency of saliva to pool in these areas is increased, constantly wetting the area, which may cause tissue maceration and favors the development of a yeast infection. As such, angular cheilitis is more commonly seen in edentulous people (people without any teeth). It is by contrast uncommon in persons who retain their natural teeth. Angular cheilitis is also commonly seen in denture wearers. Angular cheilitis is present in about 30% of people with denture-related stomatitis. It is thought that reduced vertical dimension of the lower face may be a contributing factor in up to 11% of elderly persons with angular cheilitis and in up to 18% of denture wearers who have angular cheilitis. Reduced vertical dimension can also be caused by tooth migration, wearing orthodontic appliances, and elastic tissue damage caused by ultraviolet light exposure and smoking.

Habits or conditions that keep the corners of the mouth moist might include chronic lip licking, thumb sucking (or sucking on other objects such as pens, pipes, lollipops), dental cleaning (e.g. flossing), chewing gum, hypersalivation, drooling and mouth breathing. Some consider habitual lip licking or picking to be a form of nervous tic, and do not consider this to be true angular cheilitis, instead calling it "perlèche" (derived from the French word "pourlècher" meaning "to lick one’s lips"), or "factitious cheilitis" is applied to this habit. The term "cheilocandidiasis" describes exfoliative (flaking) lesions of the lips and the skin around the lips, and is caused by a superficial candidal infection due to chronic lip licking. Less severe cases occur during cold, dry weather, and is a form of chapped lips. Individuals may lick their lips in an attempt to provide a temporary moment of relief, only serving to worsen the condition.

The sunscreen in some types of lip balm degrades over time into an irritant. Using expired lipbalm can initiate mild angular cheilitis, and when the person applies more lipbalm to alleviate the cracking, it only aggravates it. 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.

STK typically occurs in the buccal sulcus (inside the cheek) or the labial sulcus (between the lips and the teeth) and corresponds to the site where the tobacco is held in the mouth. It is painless.

The appearance of the lesion is variable depending upon the type of tobacco used, and the frequency and duration of use. It takes about 1-5 years of smokeless tobacco use for the lesion to appear. Early lesions may appear as thin, translucent and granular or wrinkled mucosa. The later lesion may appear thicker, more opaquely white and hyperkeratotic with fissures and folds. Oral snuff causes more pronounced changes in the oral mucosa than tobacco chewing. Snuff dipping is associated more with verrucous keratosis.

As well as the white changes of the oral mucosa, there may be gingival recession (receding gums) and staining of tooth roots in the area where the tobacco is held.

True hyposalivation may give the following signs and symptoms:

- Dental caries (xerostomia related caries) – Without the anticariogenic actions of saliva, tooth decay is a common feature and may progress much more aggressively than it would otherwise ("rampant caries"). It may affect tooth surfaces that are normally spared, e.g., cervical caries and root surface caries. This is often seen in patients who have had radiotherapy involving the major salivary glands, termed radiation-induced caries.

- Acid erosion. Saliva acts as a buffer and helps to prevent demineralization of teeth.

- Oral candidiasis – A loss of the antimicrobial actions of saliva may also lead to opportunistic infection with "Candida" species.

- Ascending (suppurative) sialadenitis – an infection of the major salivary glands (usually the parotid gland) that may be recurrent. It is associated with hyposalivation, as bacteria are able to enter the ductal system against the diminished flow of saliva. There may be swollen salivary glands even without acute infection, possibly caused by autoimmune involvement.

- Dysgeusia – altered taste sensation (e.g., a metallic taste) and dysosmia, altered sense of smell.

- Intraoral halitosis – possibly due to increased activity of halitogenic biofilm on the posterior dorsal tongue (although dysgeusia may cause a complaint of nongenuine halitosis in the absence of hyposalivation).

- Oral dysesthesia – a burning or tingling sensation in the mouth.

- Saliva that appears thick or ropey.

- Mucosa that appears dry.

- A lack of saliva pooling in the floor of the mouth during examination.

- Dysphagia – difficulty swallowing and chewing, especially when eating dry foods. Food may stick to the tissues during eating.

- The tongue may stick to the palate, causing a clicking noise during speech, or the lips may stick together.

- Gloves or a dental mirror may stick to the tissues.

- Fissured tongue with atrophy of the filiform papillae and a lobulated, erythematous appearance of the tongue.

- Saliva cannot be "milked" (expressed) from the parotid duct.

- Difficulty wearing dentures, e.g., when swallowing or speaking. There may be generalized mucosal soreness and ulceration of the areas covered by the denture.

- Mouth soreness and oral mucositis.

- Lipstick or food may stick to the teeth.

- A need to sip drinks frequently while talking or eating.

- Dry, sore, and cracked lips and angles of mouth.

- Thirst.

However, sometimes the clinical findings do not correlate with the symptoms experienced. E.g., a person with signs of hyposalivation may not complain of xerostomia. Conversely a person who reports experiencing xerostomia may not show signs of reduced salivary secretions (subjective xerostomia). In the latter scenario, there are often other oral symptoms suggestive of oral dysesthesia ("burning mouth syndrome"). Some symptoms outside the mouth may occur together with xerostomia.

These include:

- Xerophthalmia (dry eyes).

- Inability to cry.

- Blurred vision.

- Photophobia (light intolerance).

- Dryness of other mucosae, e.g., nasal, laryngeal, and/or genital.

- Burning sensation.

- Itching or grittiness.

- Dysphonia (voice changes).

There may also be other systemic signs and symptoms if there is an underlying cause such as Sjögren's syndrome, for example, joint pain due to associated rheumatoid arthritis.