Parotid Gland Swelling – Causes of Parotid Enlargement

A swollen parotid gland may occur for a number of reasons, which may be linked to inflammation of the gland (parotitis) with or without infection, blockage of the duct, chemical toxicity or growths in the parotid gland. Swelling may therefore present with pain and impaired functioning, or at times there may be no other symptoms that accompany the enlargement of the parotid.

Various pathologies that affect the parotid gland and lead to swelling may also affect the other salivary glands. This is discussed further swollen salivary glands. The parotid gland is located behind angle of the jaw, below and slightly in front of the ear. Swelling and tenderness will be evident in this area but may extend to the cheek and even below the mandible.

Symptoms of Parotid Gland Swelling

Parotid gland swelling may be unilateral (occurring on one side only) or bilateral (affecting both sides). It may be a gross enlargement which is clearly visible. Other symptoms that may also be present include :

  • Pain and tenderness
  • Dry mouth
  • Drooling with excessive salivation
  • Slurred speech
  • Disturbance in taste sensation

Patients may also experience :

  • Excessive thirst often accompanied by frequent urination due to dry mouth
  • Decreased appetite due to pain and impaired taste
  • Fever
  • Lymphadenopathy, especially cervical lymph nodes (swollen neck lymph nodes)

Causes of Swollen Parotid Gland

The most common causes of a sudden parotid swelling includes an infection or trauma (post-operative of after a blow to the face). Gradual and long term swelling is more likely due to autoimmune disorders, infections like HIV, calculi (stones) or tumors (both benign and malignant).

  • Infections
  • Acute bacterial infections are more likely to arise after surgery, dehydration, use of certain medication like phenothiazines or occlusion of the salivary duct due to a salivary stone (sialolithiasis). The most common acute viral infection is mumps which is more often seen in childhood.
  • Chronic infections (recurrent or persistent) are mainly seen in patients who are immunocompromised, using immune suppressant, drugs or undergoing radiation therapy. It is seen more frequently these days due to the spread of HIV.
  • Obstruction
  • A blockage of the parotid duct hampers saliva flow. This can lead to swelling, inflammation or an infection.
  • A salivary stone (sialolithiasis) is a more common cause of an obstruction but it can also arise from edema of the surrounding tissue due to trauma or impacted food.
  • Chronic Diseases
  • Autoimmune conditions like Sjogren’s syndrome
  • Sarcoidosis
  • HIV
  • Kidney failure
  • Hypothyroidism
  • Liver diseases like cirrhosis have been implicated.
  • Toxic
  • Alcohol abuse
  • Certain chronic medication
  • Industrial toxins
  • Tumors
  • This includes benign tumors like pleomorphic adenoma or cancer.
  • Intermediate changes often preceding a malignancy may also cause parotid swelling.