What Is Sialadenitis?

Overview

Sialadenitis is the inflammation of the salivary glands. It usually affects the major salivary glands: the parotid, the submandibular, and the sublingual, though most commonly it affects the parotid gland. The causes of sialadenitis are very diverse, ranging from infection, autoimmune diseases, prior history of radiotherapy of the face, or salivary calculus, requiring the assistance of a medical professional to correctly identify the cause in order to treat it. The prognosis of the disease is usually very good, most of the time with a quick recovery and minimal medical intervention.

Causes of sialadenitis

Sialadenitis can be distinguished between an acute or chronic presentation, with acute cases being caused more often by infection or obstruction of the gland, and chronic cases associated with autoimmune diseases and inflammatory reactions to head and neck radiotherapy and/or radioactive iodine therapy. Infections are the most common cause of acute sialadenitis.

Bacterial sialadenitis is caused by Staphylococcus aureus, Haemophilus influenzae, or Streptococcus pyogenes.

Viral infections are associated with mumps in most cases, which is a virus that can be transmitted through direct contact with an infected person or through respiratory droplets and saliva, making it highly contagious. It affects the parotid glands (either unilaterally (one side) or bilaterally (both sides)), causing the very characteristic swelling of mumps parotitis. Other viruses that can cause sialadenitis are the coxsackie virus and also HIV.  HIV sialadenitis can present without pain or even without any symptoms, making it very different from other forms of sialadenitis.

Obstruction of the salivary glands can also be caused by a foreign body obstruction (like a fishbone lodged into the duct).  

A sialolith (salivary calculus) can cause sialolithiasis.  This causes swelling and pain, especially when salivary flow is stimulated, and symptoms will not subside until the foreign object or sialolith is expelled from the duct.¹ The obstruction from a sialolith most often affects the submandibular duct due to its tortuous path and smaller orifice compared to the parotid duct, making an obstruction-caused sialadenitis more likely to affect the submandibular gland.² Risk factors of sialolithiasis include dry mouth (xerostomia) and dehydration.

Chronic sialadenitis, unlike acute, is usually not related to infections, but rather to autoimmune diseases. Some of them are listed below.

Sjögren syndrome is an autoimmune condition that affects the salivary and lacrimal glands.  As a result, it produces dry eyes and dry mouth, with the possibility of other symptoms such as dry skin, fatigue, and pain.  It can cause inflammation of the salivary glands, with painless swelling on one or both sides of the face.

Sarcoidosis is a disease that causes the accumulation of inflammatory cells in tissue, forming granulomas.  Symptoms may vary, depending on where the granulomas are located, but it often affects the lungs and heart. When it comes to the salivary gland, bilateral enlargement of the parotid gland with dry mouth (xerostomia) is a common finding in patients with sarcoidosis.²

Heerfordt syndrome is a particular manifestation of sarcoidosis that affects the eyes (causing uveitis, an inflammation of the eye), the parotid glands (causing parotitis), chronic fever, and even facial nerve paralysis.³

Inflammation of the salivary glands can also be caused by oral radiotherapy or radioactive iodine treatment for thyroid cancer, manifesting without fever.³ Another cause of sialadenitis includes juvenile recurrent parotitis: this is a disorder characterised by recurring inflammation of the parotid gland without a known cause, and it usually resolves itself spontaneously after puberty.

Although obstruction of the salivary gland can result in an acute episode of sialadenitis, recurring episodes of sialolithiasis increase the risk of chronic sclerosing sialadenitis, also known as Küttner's tumour, when it affects the submandibular gland. Although referred to as a tumour, it is the accumulation of inflammatory cells and sclerosis of the gland tissue (substitution of normal tissue with a type of hard connective tissue), presenting clinically as a hard mass on the gland. Abnormalities of the anatomy of the salivary glands and other autoimmune disorders have also been proposed as contributing factors, though chronic sclerosing sialadenitis has recently been classified as an IgG4-related disease due to its inflammatory nature.⁴

Signs and symptoms of sialadenitis

Acute sialadenitis can manifest in several ways including: 

• Painful swelling of the salivary gland(s) affected, which can increase and spread throughout the cheek, eye, and neck area and can cause reddening of the skin
• Fever  and a general feeling of malaise 
• If caused by an obstruction of the duct, the sialolith might be visible as a calcified stone, which can become infected with pus

Symptoms of chronic sialadenitis include:

• Little to no pain  
• Intermittent swelling of the gland (usually one side)

If associated with an autoimmune disease and depending on the cause, these symptoms might be part of a larger picture of other symptoms like:

• Dry mouth and/or eyes
• Fatigue
• Chronic pain

Management and treatment for sialadenitis

Treatment depends on the cause of the disease, but it can often be resolved fairly quickly. Treatments include: 

• Antibiotics (in the case of a bacterial infection)
• Analgesics like non-steroidal anti-inflammatory drugs (NSAID) are useful for pain, swelling, and fever
• Massages 

Sialogogues is a type of medication that increases salivary flow. Recurring or very severe sialadenitis might require surgical removal of parts of the affected gland or even its entirety, especially if related to sialolithiasis or chronic sclerosing (scarring) sialadenitis, though this is a last resource option.

Diagnosis

A correct diagnosis requires a medical examination.  According to the British Medical Journal Best Practice (BMJ), there are signs and symptoms that should be observed.

Pain is usually present and if the pain worsens just before or during meals, when there should be a greater flow of saliva - this could indicate a sialolith.

Fever points to an infection.  A moderate fever that suddenly speaks points to the formation of an abscess and worsening of the infection.

Facial swelling can be acute onset intermittent.  Intermittent swelling points to chronic disease; if oedema worsens before or during meals, it could also point to a sialolith; excessive swelling can also lead to mandibular trismus and/or respiratory distress

Presence of pus is an indicative of an infection.

Dryness of the eyes and mouth these symptoms could point to a chronic condition like Sjögren syndrome or other connective tissue diseases.

History of medication and surgery under general anaesthesia as certain types of medication, like antidepressants and anticholinergics, can cause dry mouth (xerostomia), which poses a greater risk of sialolithiasis, as well as general anaesthetics.

Oral candidiasis (thrush) is an opportunistic disease that can point to a chronic xerostomia problem (related to medication or an autoimmune disease like Sjögren syndrome) or to an immunity problem like an HIV infection.

Cranial nerve palsy could happen because of compression of nerves due to swelling, or point to Heerfordt syndrome.

A full blood count can be performed to confirm or rule out infection, as well as a culture test to determine the best antibiotic to treat bacterial sialadenitis. Facial radiographs like occlusal radiography can be taken in order to identify a sialolith, though it isn’t always visible if not calcified enough. Other tests like an ultrasound, an MRI, or a CT scan can be performed to identify masses or foreign bodies in deep glandular tissue and help aid diagnosis.

FAQs

How can I prevent sialadenitis?

It can be prevented in many ways, depending on what’s causing the disease. 

Infections can be prevented by: 

• Avoiding contact with sick individuals 
• Washing hands
• Brushing and flossing your teeth, taking care of dental prosthetics etc
• Vaccination against  mumps 

Salivary calculus can be avoided by drinking lots of water regularly. If you have xerostomia (dry mouth), you should seek medical advice to determine the cause. It may  be dehydration, a side effect of a medication, or another condition you might not be aware of.People who have autoimmune diseases or chronic conditions that predispose them to sialadenitis (such as a history of head and neck radiotherapy, iodine radioactive therapy, or juvenile recurrent parotitis) should receive dental and medical attention regularly; if necessary, your physician or dentist might prescribe artificial saliva to help with xerostomia.

How common is sialadenitis?

It is one of the most common diseases that can affect the salivary glands. It is estimated that 0.001 to 0.002% of hospitalizations in the United States are caused by sialadenitis.

Who is at risk of sialadenitis?

Older patients in their 50s or 60s, those with xerostomia (either caused by medication, another condition, or simply idiopathic), and those with  Sjögren syndrome are more at risk of having sialadenitis. Teenagers and adults with anorexia nervosa, children with juvenile recurrent parotitis, and patients who have received oral radiotherapy and/or radioactive iodine treatment for thyroid cancer as being at risk of developing sialadenitis.

Is sialadenitis contagious?

Sialadenitis itself is not contagious. However, if it is caused by an infection (bacterial or viral), it is contagious and can be transmitted to others. Mumps, for instance, is highly contagious and can be transmitted through direct contact, respiratory droplets, or saliva.

When should I see a doctor?

If you have facial swelling, pain, fever, difficulty breathing, or opening the mouth, you should see a doctor. Sialadenitis, although mild in most cases, should be taken seriously due to its complications. 

The most immediate complication of sialadenitis is an abscess, which is a collection of pus: bacteria, dead tissue, and white blood cells. Antibiotic therapy is required and drainage should be performed to avoid other complications of the spreading infection, like cellulitis and Ludwig’s angina.

In the long-term, sialadenitis, especially if recurring, can affect the salivary gland’s ability to produce saliva, causing xerostomia. This can favour tooth decay and the formation of dental cavities, as saliva protects against harmful bacteria and demineralization of the enamel.

If surgical intervention is required, post-surgery infection is a risk, as well as facial nerve palsy. Although not permanent in most cases, there is a risk of permanent nerve damage and paralysis of the face after surgery to remove sections or the whole parotid gland, for example.¹

Summary

Sialadenitis is the (acute or chronic) inflammation of the salivary gland(s). caused by infection, sialolithiasis, obstruction of the gland, autoimmune diseases, or as a consequence of facial radiotherapy. Symptoms often include pain and swelling and can be accompanied by fever and fatigue. It is important to correctly diagnose the cause of sialadenitis in order to treat beyond the symptoms and identify the cause.