Signs and Symptoms
- Variable size of the swelling, typically soft
- Swelling can occur on one side or both sides
- Usually non-tender, but pain may be present
- Resolves over minutes to hours, occasionally taking days
- Can be transient or recurrent

Causes
- Caused by raised air pressure in the mouth

Diagnosis and Management
- Often misdiagnosed and incorrectly managed
- Diagnosis based mainly on the history
- Crepitus may be elicited on palpation of the parotid swelling
- Massaging the gland may produce frothy saliva or air bubbles
- Further investigations may show air in the parotid gland and duct

Prognosis
- Recurrent pneumoparotitis may lead to sialectasis, recurrent parotitis, and subcutaneous emphysema
- Can potentially result in pneumothorax
- Predisposes to complications in the face, neck, and mediastinum

Epidemiology
- A rare condition
- More likely to occur in individuals with raised pressure in the mouth (e.g., wind instrument players, balloon and glass-blowers)
- Reported cases associated with activities such as bicycle tire inflation, whistling, nose blowing, coughing, and valsalva maneuver
- Can be an iatrogenic effect of dental treatment, spirometry, and positive pressure ventilation
- Mainly occurs in adolescents, often self-inflicted due to psychological issues