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