Understanding Sebaceous Cysts in Dogs
Where Did This Lump Come From?
Sebaceous glands are microscopic little things that secrete an oily or waxy matter known as "keratin." You may not have been aware of your dog's sebaceous glands until they started getting irritated and formed an unsightly cyst.
You actually need to thank those tiny glands for your dog's glossy, shiny coat. Frequent brushing is what stimulates the glands to release oils that moisturize Rover's skin and makes his coat nice and shiny. In fact, brushing regularly keeps those glands active and happy and can prevent cyst growth.
The problems start when a pore or hair follicle of one of these glands is obstructed, causing the buildup of oil. Eventually, a cyst will form if the gland remains blocked.
What Are Sebaceous Cysts and Why Do They Form?
Also known as epidermoid or epidermal inclusion cysts, a sebaceous cyst is a swelling in the skin caused by a clogged sebaceous gland.
- They are generally smooth, round growths that measure anywhere between 5 mm to 5 cm in diameter.
- When they are caused by a clogged sweat gland, they appear as translucent, dark, or bluish nodules that are often found around the eyes or ears.
- They are normally not harmful and do not need to be removed, unless they grow big and start impairing movement or interfering with a dog's normal activities.
- For examples of impairment, a cyst on a paw pad may interfere with walking, and a cyst on the eyelid (called a meibomian gland adenoma) may cause excessive blinking or rub against the cornea of the eye.
Complications can occur when the cyst ruptures and becomes open, which could lead to infection. Cysts that grow very quickly are also abnormal.
If left alone, one of three things will happen:
- The cysts will resolve themselves and disappear.
- They will burst and leak.
- They will become "walled off," and will neither grow nor disappear, remaining as small lumps underneath the skin.
Why Do the Glands Clog?
Clogs can be caused by dirt, an infection, local injury, or sebum that gets so thick it cannot make it through the pore's opening. Sebum is another name for the stuff that sebaceous glands make. Once clogged, the oily matter must go somewhere, so a sac forms, creating the cyst.
Some breeds, such as the Schnauzer or the Yorkie, may also be genetically predisposed to developing cysts.
The first sign of a sebaceous cyst is usually noticing a lump or a bump that was not there on your dog before. Sebaceous cysts do not usually cause the dog any pain.
In fact, owners find them to be more of a nuisance because they are an eyesore. At times, however, the cysts can become bothersome, interfering with movement or getting infected.
Sometimes the buildup of oily matter is so great that the cyst ruptures. In that case, it's a good idea to check for signs of infection at least two or three times every day. If the dog licks, rubs, or scratches at the cyst repeatedly, there is a greater chance of infection (more on this below).
Should You Go to the Vet?
While a sebaceous cyst may just sit there and not bother your dog at all, it is important to have it checked out by a vet (even though it is probably not an emergency). Just as you would have a new lump in your breast checked out by a doctor or a new mole checked by a dermatologist, it's best to have Rover see the vet for peace of mind.
This is especially important because there are some types of cancers known as "the great imitators" because they look quite innocent when they're really not. Don't gamble with your dog's health. Please see your vet to have any suspicious lump or bump checked out!
Your vet has a couple of ways to find out what your dog's bump is.
Fine Needle Aspiration
A fine needle aspiration may help reveal the type of lump your dog has, but it's not as accurate as a tissue biopsy (discussed below). In this procedure, a needle is used to draw a sample of cells. The collected material is then placed on a glass slide and examined in the hospital or sent off to a pathologist for cytology. Generally, if the lump deflates and exudes a cheesy gray, brown, or yellowish material once the needle is inserted, it is likely (though not definitively) a cyst.
This is not a sure-fire diagnosis method, however, since lumps are often not homogeneous (the same throughout). It's comparable to inserting a straw into a mixed berry and peach pie covered by a tea towel. When you insert the straw and draw a sample to examine, you may not be sure what type of pie it is. If you collected some peaches, you might think it's a peach pie. If you got just crust and berry sauce, you might think it was something else.
Another, more accurate way to rule out cancer is through tissue biopsy. In this case, the procedure is more expensive and invasive, but the results are also more accurate.
For a tissue biopsy, your dog will need a local anesthetic as the vet will remove a piece of the lump so it can be sent to histopathology and analyzed. If the lump is found to be malignant, your dog will need to have it totally removed.
For this procedure, your dog will go straight to surgery to have the entire lump removed. This is the most costly option, but it's also the best to get a proper diagnosis as the whole lump is sent to pathology.
Another advantage is that the entire mass will be gone, which is good if it was impairing movement or bothering the dog. The main disadvantage is that it's the most invasive option and the dog will be under total anesthesia. Since the operating vet doesn't know what the lump is, he may be removing something benign.
Of course, there are no black-and-white rules when it comes to the best method for diagnosis. Depending on where the lump is, its size, and appearance, the vet may take a more conservative or drastic approach.
Removal and Resolution
Treating a sebaceous cyst is not easy. If you try a home treatment, you may not have much luck as the underlying issue often remains.
Cysts often will not disappear unless the entire sac is removed. This is something that only a veterinarian can do through surgery, which is only recommended when cysts recur, are prone to infections, or impair your dog's quality of life. Consult with your vet for the best option.
Also, cysts don't like to stay empty. Even when they rupture or are drained, they tend to fill up again and you're soon back to where you started. However, there are some instances where cysts have gone away on their own and where home remedies have worked.
In general if it's at all an option and if the cyst doesn't appear to be bothering the dog, it's better to leave it alone.
Trouble Signs of Cysts
If the Cyst . . .
Causes other kind of discomfort (i.e. is on the eyelid)
Ruptures and becomes infected
Grows very rapidly
Should You Try to Squeeze It?
As tempting as it may be to squeeze a cyst, according to Vetinfo you can actually hurt your pet. Also, removal under non-sterile conditions may result in infection, causing an even bigger problem.
Dr. Karen Becker also doesn't recommend squeezing cysts for the simple fact that they may implode (burst under the skin), potentially causing a bacterial skin infection known as cellulitis. For more about cysts, their treatment, and prevention, watch Dr. Karen Becker's video below.
What If It Ruptures?
When a cyst ruptures, it's important to keep it free from bacteria and make sure the dog does not pester it. To keep bacteria levels low and reduce risk of infection:
- Do not keep the area bandaged all of the time. This will increase moisture and the chance for bacteria growth.
- Keep your dog from licking or disturbing the wound (e-collars can help with this. I like this one.) comfy cone
- Trim the hair around the cyst. This will keep the hair from matting around it, trapping bacteria and moisture.
Be sure to keep the area clean and check it for infection frequently. If you notice any of the below, it's time to go to the vet:
- Foul-smelling discharge
Dr. Karen Becker Discusses Sebaceous Cysts in Dogs
*Disclaimer: This article is not to be used for diagnostic purposes or a substitute for professional veterinarian advice. If your dog has a lump or bump, see your vet and make sure to rule out any serious conditions. By reading this article you accept this disclaimer.
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This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.