Pneumoparotitis is often misdiagnosed and incorrectly managed. The diagnosis is based mainly on the history. Crepitus may be elicited on palpation of the parotid swelling, and massaging the gland may give rise to frothy saliva or air bubbles from the parotid papilla. Further investigations are not typically required, however sialography, ultrasound and computed tomography may all show air in the parotid gland and duct.

Management is simply by avoidance of the activity causing raised intraoral pressure which is triggering this rare condition.

The size of the swelling is variable, but it is soft and can occur on one side or both sides. It is typically non tender, although sometimes there may be pain. It usually resolves over minutes to hours, however occasionally this may take days. The condition can be transient or recurrent.

Phlegmon is a spreading diffuse inflammatory process with formation of purulent exudate (the suppuration of pus). This is the result of acute purulent inflammation which may be related to bacterial infection; however, the term 'phlegmon' (from Greek 'phlegmone', inflammation) mostly refers to a walled-off inflammatory mass without bacterial infection, one that may be palpable on physical examination.

An example would be phlegmon of diverticulitis. In this case a patient would present to the emergency department with left lower-quadrant abdominal tenderness, and the diagnosis of sigmoid diverticulitis would be high on the differential diagnosis, yet the best test to confirm it would be CT scan.

Another example, phlegmon affecting the spine, is known as spondylodiscitis and is associated with endplate destruction and loss of disc height. In adults, the bone marrow is affected first, while in children, the disease starts in the disc itself and spreads rapidly to the adjacent vertebral bodies. Phlegmon in the spine can be a diffuse enhancement, or localized abscess, (peripheral enhancement) in the epidural, subligamentous or paraspinous spaces. Under MRI examination, phlegmon will show dark with T1, and high signal (bright) with T2.

"Chronic nonspecific parotitis:"

This term is generally used for patients in whom no definite cause is found. Episodes may last for several days, paralleling the time course of a bacterial or viral illness. Others may experience episodes that last only a few hours from onset to resolution. Some episodes may last for several weeks. Quiescent periods between episodes last for hours, days, or even years.

"Recurrent parotitis of childhood:"

An uncommon syndrome in which recurring episodes clinically resembling mumps. Generally, episodes begin by age 5 years, and virtually all patients become asymptomatic by age 10–15 years. The duration of attacks averages 3–7 days but may last 2–3 weeks in some individuals. The spectrum varies from mild and infrequent attacks to episodes so frequent that they prevent regular school attendance.

Local heat applied to the gland, massaging the gland from back to front, and taking penicillin usually cure individual episodes. Treatment of individual infections may prevent injury to the gland parenchyma. Severe disease may be treated by parotidectomy.

"Sialadenosis (sialosis):"

In this disorder, both parotid glands may be diffusely enlarged with only modest symptoms. Patients are aged 20–60 years at onset, and the sexes are equally involved. The glands are soft and non-tender. Approximately half of the patients have endocrine disorders such as diabetes, nutritional disorders such as pellagra or kwashiorkor, or have taken drugs such as guanethidine, thioridazine, or isoprenaline.

"Sarcoidosis:"

The lungs, skin, and lymph nodes are most often affected, but the salivary glands are involved in approximately 10% of cases. Bilateral firm, smooth, and non-tender parotid enlargement is classic. Xerostomia occasionally occurs. The Heerfordt-Waldenstrom syndrome consists of sarcoidosis with parotid enlargement, fever, anterior uveitis, and facial nerve palsy.

"IgG4-related sialadenitis":

This term refers to IgG4-related disease (IgG4-RD) involving any of the major salivary glands, i.e. parotid or submandibular glands. This is often symmetrical and is usually associated with manifestations of IgG4-RD elsewhere in the body. IgG4-related sialadenitis is particularly associated with involvement of one or both of the lacrimal glands (referred to as IgG4-related dacryo-sialadenitis). "Mikulicz's disease", now considered to be a subtype of IgG4-related disease, was a term used when (i) any two of the parotid, submandibular and lacrimal glands were persistently and symmetrically enlarged and (ii) other diseases that may mimic this presentation were excluded.

"Pneumoparotitis:"

Air within the ducts of the parotid gland with or without inflammation. The duct orifice normally functions as a valve to prevent air from entering the gland from a pressurized oral cavity. Rarely, an incompetent valve allows insufflation of air into the duct system. Pneumoparotitis most commonly occurs in wind instrument players, glass blowers, and scuba divers.

Several lymph nodes reside within the parotid gland as a superficial and deep group of nodes. These nodes may be involved with any process that affects lymph nodes, including bacterial, fungal, viral, and neoplastic processes. Rarely, drugs such as iodides, phenylbutazone, thiouracil, isoproterenol, heavy metals, sulfisoxazole, and phenothiazines cause parotid swelling.

"Dehydration:"

This is a common, non-infectious cause of parotitis. It may occur in elderly or after surgery.

Systemic features of infection such as increased body temperature (up to 38-40 °C), general fatigue, chills, sweatings, headache, loss of appetite).

Inflammatory signs – dolor (localized pain), calor (increase local tissue temperature), rubor (skin redness/hyperemia), tumor (either clear or non-clear bordered tissue swelling), functio laesa (diminish affected function).

NB: severity of patient condition with phlegmons is directly proportional to the degree of intoxication level i.e. the more severe the condition, the higher the degree of intoxication level.

A noninfectious occurrence of phlegmon can be found in the acute pancreatitis of Systemic Lupus Erythematosus. The immunosuppressive aspects of this disease and the immunosuppressive medications used to treat it blunt each of the signs of infection.

Swelling may be severe enough to put pressure on the eye and distort vision. Some patients first thought to have dacryoadenitis may turn out to have a malignancy of the lacrimal gland.

Dacryoadenitis is inflammation of the lacrimal glands (the tear-producing glands).

Rhinoliths present as unilateral nasal obstruction. Foul-smelling, blood-stained discharge is often present. Epistaxis and pain may occur due to the ulceration of surrounding mucosa.

The location is often gravity dependent, and depends on the patient position. Generally, the right middle and lower lung lobes are the most common sites affected, due to the larger caliber and more vertical orientation of the right mainstem bronchus. Patients who aspirate while standing can have bilateral lower lung lobe infiltrates. The right upper lobe is a common area of consolidation in alcoholics who aspirate in the prone position.

Hypersalivation (also called ptyalism or sialorrhea) is excessive production of saliva. It has also been defined as increased amount of saliva in the mouth, which may also be caused by decreased clearance of saliva.

Hypersalivation can contribute to drooling if there is an inability to keep the mouth closed or in difficulty in swallowing the excess saliva (dysphagia) and lead to excessive spitting.

Hypersalivation also often precedes emesis (vomiting), where it accompanies nausea (a feeling of needing to vomit).

Aspiration pneumonia is often caused by a defective swallowing mechanism, often due to a neurological disease or as the result of an injury that directly impairs swallowing or interferes with consciousness. Examples of the former are stroke, Parkinson's disease, and multiple sclerosis, and examples of the latter are some types of dementia, seizures, intoxication, and general anaesthesia. For many types of surgical operations, patients are therefore instructed to take nothing by mouth (nil per os, abbreviated as NPO) for at least four hours before surgery.

Congenital disorders of the salivary glands are rare, but may include:

- Aplasia

- Atresia

- Ectopic salivary gland tissue

- Stafne defect - an uncommon condition which some consider to be an anatomic variant rather than a true disease. It is thought to be created by an ectopic portion of salivary gland tissue which causes the bone of the mandible to remodel around the tissue, creating an apparent cyst like radiolucent area on radiographs. Classically, this lesion is discovered as a chance finding, since it causes no symptoms. It appears below the inferior alveolar nerve canal in the posterior region of the mandible.

Infections involving the salivary glands can be viral or bacterial (or rarely fungal).

- Mumps is the most common viral sialadenitis. It usually occurs in children, and there is preauricular pain (pain felt in front of the ear), swelling of the parotid, fever, chills, and headaches.

- Bacterial sialadentitis is usually caused by ascending organisms from the oral cavity. Risk factors include reduced salivary flow rate.

- Human immunodeficiency virus-associated salivary gland disease (HIV-SGD).

Mendelson's syndrome is characterised by a bronchopulmonary reaction following aspiration of gastric contents during general anaesthesia due to abolition of the laryngeal reflexes. The main clinical features are signs of general hypoxia, two to five hours after anaesthesia. Such features may include cyanosis, dyspnea, fever, pulmonary wheeze, crepitant rales, rhonchi, and tachycardia with a low blood pressure. Decreased arterial oxygen tension is also likely to be evident. Pulmonary edema can cause sudden death or death may occur later from pulmonary complications.

An exanthem or exanthema (from Greek ἐξάνθημα "exánthēma", "a breaking out") is a widespread rash usually occurring in children. An exanthem can be caused by toxins, drugs, or microorganisms, or can result from autoimmune disease.

It can be contrasted with an enanthem.

Mendelson's syndrome is chemical pneumonitis or aspiration pneumonitis caused by aspiration during anaesthesia, especially during pregnancy. Aspiration contents may include gastric juice, blood, bile, water or an association of them.

A rhinolith is a calculus present in the nasal cavity. The word is derived from the roots "" and "", literally meaning "nose stone". It is an uncommon medical phenomenon, not to be confused with dried nasal mucus. A rhinolith usually forms around the nucleus of a small exogenous foreign body, blood clot or secretion by slow deposition of calcium and magnesium salts. Over a period of time, they grow into large irregular masses that fill the nasal cavity. They may cause pressure necrosis of the nasal septum or lateral wall of nose. Rhinoliths can cause nasal obstruction, epistaxis, headache, sinusitis and epiphora. They can be diagnosed from the history with unilateral foul smelling blood stained nasal discharge or by anterior rhinoscopy. On probing probe can be passed around all its corners. In both CT and MRI rhinolith will appear like a radiopaque irregular material. Small rhinoliths can be removed by foreign body hook. Whereas large rhinoliths can be removed either by crushing with luc's forceps or by Moore's lateral rhinotomy approach.

Pilonidal cysts are itchy and are often very painful, and typically occur between the ages of 15 and 35. Although usually found near the coccyx, the condition can also affect the navel, armpit or genital region, though these locations are much rarer.

Symptoms include:

- Pain/discomfort or swelling above the anus or near the tailbone that comes and goes

- Opaque yellow (purulent) or bloody discharge from the tailbone area

- Unexpected moisture in the tailbone region

- Discomfort with sitting on the tailbone, doing sit-ups or riding a bike (any activities that roll over the tailbone area)

Some people with a pilonidal cyst will be asymptomatic.

Conditions that can cause saliva overproduction include:

- Rabies

- Pellagra (niacin or Vitamin B3 deficiency)

- Gastroesophageal reflux disease, in such cases specifically called a water brash, and is characterized by a sour fluid or almost tasteless saliva in the mouth

- Gastroparesis (main symptoms are nausea, vomiting, and reflux)

- Pregnancy

- Excessive starch intake

- Anxiety (common sign of separation anxiety in dogs)

- Pancreatitis

- Liver disease

- Serotonin syndrome

- Mouth ulcers

- Oral infections

Medications that can cause overproduction of saliva include:

- aripiprazole

- clozapine

- pilocarpine

- ketamine

- potassium chlorate

- risperidone

- rabeprazole sodium (Aciphex)

Toxins that can cause hypersalivation include:

- mercury

- copper

- organophosphates (insecticide)

- arsenic

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.

Pilonidal disease is a type of skin infection which typically occurs between the cheeks of the buttocks and often at the upper end. Symptoms may include pain, swelling, and redness. There may also be drainage of fluid. It rarely results in a fever.

Risk factors include obesity, family history, prolonged sitting, greater amounts of hair, and not enough exercise. The underlying mechanism is believed to involve a mechanical process. The lesions may contains hair and skin debris. Diagnosis is based on symptoms and examination.

If there is infection, treatment is generally by incision and drainage just off the midline. Shaving the area may prevent recurrence. More extensive surgery may be required if the disease recurs. Antibiotics are generally not needed. Without treatment the condition may remain long term.

About 3 per 10,000 people are affected a year. It occurs more often in males than females. Often it occurs in young adulthood. The term means "nest of hair". It was first described in 1833.

Bacterial

- (Plaque-induced) gingivitis—A common periodontal (gum) disease is Gingivitis. Periodontal refers to the area the infection affects, which include the teeth, gums, and tissues surrounding the teeth. Bacteria cause inflammation of the gums which become red, swollen and can bleed easily. The bacteria along with mucus form a sticky colorless substance called plaque which harbours the bacteria. Plaque that is not removed by brushing and flossing hardens to form tartar that brushing doesn't clean. Smoking is a major risk factor. Treatment of gingivitis is dependent on how severe and how far the disease has progressed. If the disease is not too severe it is possible to treat it with chlorhexidine rinse and brushing with fluoride toothpaste to kill the bacteria and remove the plaque, but once the infection has progressed antibiotics may be needed to kill the bacteria.

- Periodontitis—When gingivitis is not treated it can advance to periodontitis, when the gums pull away from the teeth and form pockets that harbor the bacteria. Bacterial toxins and the body's natural defenses start to break down the bone and connective tissues. The tooth may eventually become loose and have to be removed.

- Scarlet fever is caused by streptococci species, and starts as tonsilitis and pharyngitis before involving the soft palate and the tongue. It usually occurs in children where a fever occurs and a rash develops on the skin. It is treated with penicillin and the prognosis is generally excellent.

Viral

- Herpes simplex (infection with herpes simplex virus, or HSV) is very common in the mouth and lips. This virus can cause blisters and sores around the mouth (herpetic gingivostomatitis) and lips (herpes labialis). HSV infections tend to recur periodically. Although many people get infected with the virus, only 10% actually develop the sores. The sores may last anywhere from 3–10 days and are very infectious. Some people have recurrences either in the same location or at a nearby site. Unless the individual has an impaired immune system, e.g., owing to HIV or cancer-related immune suppression, recurrent infections tend to be mild in nature and may be brought on by stress, sun, menstrual periods, trauma or physical stress.

- Mumps of the salivary glands is a viral infection of the parotid glands. This results in painful swelling at the sides of the mouth in both adults and children. The infection is quite contagious. Today mumps is prevented by getting vaccinated in infancy. There is no specific treatment for mumps except for hydration and painkillers. Sometimes mumps can cause inflammation of the brain, testicular swelling or hearing loss.

Fungal

- Oral candidiasis is by far the most common fungal infection that occurs in the mouth. It usually occurs in immunocompromised individuals. Individuals who have undergone a transplant, HIV, cancer or use corticosteroids commonly develop candida of the mouth and oral cavity. Other risk factors are dentures and tongue piercing. The typical signs are a white patch that may be associated with burning, soreness, irritation or a white cheesy like appearance. Once the diagnosis is made, candida can be treated with a variety of anti fungal drugs.

Hunner's Ulcers can only be accurately diagnosed via a cystoscopy with hydrodistention. The procedure is performed by a urologist either as an in office procedure or while the patient is under general anaesthesia as a day surgery.

Hunner's Ulcers occur in 5 to 10 percent of people who have the bladder disease Interstitial cystitis. They form on the wall of the bladder and, like any ulcer, they can bleed, ooze, and may vary in size. They were first described by Dr. Guy LeRoy Hunner, 1868–1957, a Johns Hopkins gynecologist, in a paper delivered to the Boston Medical Society in 1915.