Salivary Gland Swelling in Dogs

There are several categories into which salivary gland swelling falls, each having a variety of causative factors.  These swellings of the salivary glands result in puffiness or “swellings” in the head and neck area where the salivary glands are located.  Many of the salivary gland swellings seen in dogs are benign while others are not. Any swelling warrants investigation. If you notice your pet drooling, if he has lost his appetite, or if you see that he is vomiting or regurgitating, a veterinary visit is warranted.

Salivary gland swelling in dogs is a condition which can develop from a variety of reasons and disorders, causing a swelling in the head and/or neck of the canine.

Some of the symptoms of salivary gland swelling in dogs may not be a surprise to you at all, given the very simple name of the condition, while other symptoms may be new to you:

• Enlargement of an area anywhere on the neck and/or head of the canine
• Drooling or leaking saliva
• Enlargement may be painful to touch or palpation or not  
• May be intermittent or constant
• Fever
• Depression
• Mucous discharge
• Can be bilateral or unilateral
• Anorexia
• Weight loss
• Vomiting
• Regurgitation
• Gagging

Types  

There are three basic types or categories of salivary gland swelling disorders:

• Inflammatory - Can be caused by infection or foreign body presence
• Neoplastic - Another term for a malignant cancer which is more commonly found in older canines
• Traumatic -  This type can be caused by bites, blunt trauma to the head, oral injuries, salivary stones, ruptures to the salivary glands or the ductwork to which they are connected

Within the above three types or categories of salivary gland swelling in dogs, there are four main salivary disorders commonly found in dogs:

Mucoceles

These are like cysts (usually fluid filled) resulting from a trauma which has damaged or ruptured the salivary and allowed salivary fluid to leak into the surrounding tissues.

Neoplasms

This is a tumor. Although this is relatively rare in dogs and cats, it seems that it is more frequently found in cats than in dogs.  And, when found in either species: 

• The afflicted animal is usually over ten years old
• While there is no particular breed associated, it seems that Poodles and Spaniels may be somewhat predisposed
• Most are malignant, with carcinoma and adenocarcinoma being the most prominent type
• Infiltration and metastasis to local or adjacent lymph nodes or lungs is both possible and common
• They tend to recur after excision
• They respond well to radiotherapy whether surgical options are utilized or not

Sialadenitis

This is an inflammation of the salivary gland  and can be caused by trauma from penetrating wounds or systemic infection which affects the salivary gland or the nearby tissue. It has been reported as a component in systemic diseases like rabies, distemper and the paramyxovirus which is responsible for causing mumps in humans.

Sialometaplasia

Also called necrotizing sialometaplasia or salivary gland necrosis or infarction, this is caused by squamous changes in the cells of the various parts of the salivary components (ducts and lobules) with ischemic necrosis (death of tissue due to lack of blood supply) in the salivary gland lobules. It is mostly found in small breeds like Terriers who are between 3 and 8 years old.

Diagnosis will likely begin with a complete history provided to your veterinary professional that includes the symptoms noted, the severity and duration of those symptoms, elimination habits, dietary regimens and eating patterns along with your assessment of the attitudes and behaviors noted in your family pet.  Your vet will need to do a physical examination of the afflicted pet which will include palpation (touching and applying a little pressure) of the swollen nodule and the surrounding tissue.  This is necessary to determine if the swollen area is an abscess, tumor or a variety of retention cysts, and, based upon the findings, the vet may order additional testing.  

He may need to get sialography,also called radio sialography, (radiographic imaging of the salivary tract) to get a better appreciation of the swelling site.  He will likely need blood chemistry evaluation to ascertain if there is any infection and inflammation present.  The vet will likely also need a specimen of the fluid which has accumulated in the salivary gland area for laboratory review and analysis. Once your veterinary professional has gathered all of the information from the testing various modalities chosen, he will develop and initiate an appropriate treatment plan.

Treatment options for salivary gland swelling in dogs ranges in intensity.  Here are some of the options which your veterinary professional will be considering when he develops the appropriate treatment plan for your canine family member:

• Aspiration of salivary gland swelling is a temporary solution and will likely need to be repeated several weeks or months down the road; this option has the potential to introduce bacteria into the area, making an infection more likely if one has not already developed
• Surgical removal of the salivary gland and those mandibular and sublingual glands located on both sides of the affected area of swelling
• Sometimes a marsupialization procedure is utilized in addition to the surgical removal of the mandibular and sublingual glands in an attempt to help drain the fluid into the oral cavity; marsupialization is a procedure which involves making an elliptical cut in certain areas of the cystic lesion and suturing it to the rim of the oral mucosa
• Sometimes, a drain is placed in the area of swelling to allow drainage from the area while it heals
• Surgical removal of the tumor if that is the source of the swelling
• Accompanying radiation of the areas affected and adjacent to the tumor removal site

Other treatment options which can be added to any of the above would include medications given for bacterial infections and anti inflammatory medications to help ease any discomfort and promote the healing process.

In most cases, recovery of your doggy family member with timely and appropriate treatment generally has a good prognosis.  Don’t worry about the surgical removal of the infected, inflamed or ruptured salivary glands seeming like a drastic procedure as the canine salivary tract has an abundance of salivary glands.  There will be plenty of salivary glands remaining to perform the necessary functions of that canine system.  Your doggy family member will not suffer any ill effects from the absence of some of these glands.  

Of course, if your pet has a malignant tumor at the root of the salivary gland swelling, then prognosis may not be as good especially in view of the fact that recurrence and infiltration and metastasis to nearby tissue is fairly common.  But, it is important to understand that many of these tumors are treatable in dogs if discovered early on.  Radiotherapy combined with surgery or without surgery has been shown to be the best option for treatment of malignancies.