Etymology
- Greek word παρωτῖτις (νόσος) means 'disease of the parotid gland'
- παρωτίς (stem παρωτιδ-) means 'gland behind the ear'
- οὖς (stem ὠτ-, ōt-) means 'ear'
- παρά - pará means 'behind'
- Etymology of the term parotitis is derived from Greek words related to the location and gland involved

Causes
- Dehydration can be a non-infectious cause of parotitis, especially in elderly individuals or after surgery
- Acute bacterial parotitis is often caused by Staphylococcus aureus or other commensal bacteria
- Parotitis can also be caused by extrapulmonary tuberculosis, with symptoms including cough, fever, weight loss, and chest pain
- Mumps, caused by Paramyxovirus, is a common viral cause of parotitis
- HIV infection can lead to parotitis, often associated with generalised lymphadenopathy and dry mouth

Autoimmune causes
- Sjögren's syndrome is an autoimmune disease characterised by chronic inflammation of the salivary glands, including the parotid gland
- Lymphoepithelial lesion of Godwin is a tumor associated with Sjögren's syndrome
- Chronic autoimmune parotitis, also known as chronic punctate parotitis, is a group of autoimmune causes of parotitis
- The prevalence of parotitis in women with Sjögren's syndrome is approximately 9 times higher than in men
- The cause of autoimmune parotitis is unknown, but it is often accompanied by excessive dryness in various parts of the body

Blockage
- Acute parotitis can be caused by blockage of the main parotid duct or its branches
- Blockage may be due to salivary stones, mucous plugs, or rarely, tumors
- Salivary stones, also known as sialolithiasis, are mainly composed of calcium
- Duct stricture, infection, or injury can also cause blockage and inflammation of the parotid gland
- Symptoms of blockage may include recurrent swelling, pain, and aggravation during eating

Diseases of uncertain cause
- Chronic nonspecific parotitis refers to cases where no definite cause is found
- Recurrent parotitis of childhood, also known as juvenile recurrent parotitis (JRP), is a syndrome characterised by recurring episodes similar to mumps
- Sialadenosis, or sialosis, is a disorder where both parotid glands are diffusely enlarged with modest symptoms
- Sarcoidosis, a systemic disease, can also affect the salivary glands in approximately 10% of cases
- The cause of these diseases is uncertain, and they may have various associated factors such as endocrine disorders or drug use.