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Understanding Sebaceous Cysts in Dogs: What Are They and What Should You Do?

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

If you find an odd bump on your dog, it could be a sebaceous cyst. Learn more about these swellings and when to see the vet.

If you find an odd bump on your dog, it could be a sebaceous cyst. Learn more about these swellings and when to see the vet.

What Is This Lump on My Dog?

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 make 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.

This is a diagram of the sebaceous gland which, when blocked, can lead to a cyst.

This is a diagram of the sebaceous gland which, when blocked, can lead to a cyst.

What Are Sebaceous Cysts and Why Do They Form?

Also known as an epidermoid or epidermal inclusion cyst, a sebaceous cyst is a swelling in the skin caused by a clogged sebaceous gland.

Cyst Characteristics

  • They are generally smooth, round growths that measure anywhere between five mm and five 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 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.

Should I Leave a Cyst Alone?

If left alone, one of three things will happen:

  1. The cysts will resolve themselves and disappear.
  2. They will burst and leak.
  3. 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.

How Do I Know If It's a Sebaceous Cyst?

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!

This is a small follicular cyst that my dog had.

This is a small follicular cyst that my dog had.

How Will the Vet Diagnose the Bump?

Your vet has three ways to find out what your dog's bump is.

1. 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.

2. Tissue Biopsy

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.

3. Excisional Biopsy

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 its appearance, the vet may take a more conservative or drastic approach.

Are There Home Remedies for Sebaceous Cysts? Can They Be Removed?

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.

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.

Only Vets Can Fully Remove Cysts

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.

Leave the Cyst Alone, If Possible

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 has any of these qualities, you should have it examined and possibly removed:

  • Impairs movement
  • Causes other kinds of discomfort (i.e. is on the eyelid)
  • Ruptures and becomes infected
  • Grows very rapidly

Should You Try to Squeeze or Pop a Cyst?

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 the Cyst Ruptures or Leaks?

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 comfy cone one.)
  • Trim the hair around the cyst. This will keep the hair from matting around it, trapping bacteria and moisture.

Go to the Vet If You Notice These Signs

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:

  • Redness
  • Swelling
  • Foul-smelling discharge
  • Pus
  • Pain

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.

Questions & Answers

Question: Our 10-year-old Cairn Terrier had a cyst rupture today. A bloody, brown and blackish substance oozed from it. I washed him off, and in the process, more fluid oozed. I squeezed it a bit, and more came out. Did I do more damage than good? Can I just clean it up and keep an eye on him?

Answer: If this is indeed a benign sebaceous cyst (confirmed by your vet by taking a sample and having it analyzed under a microscope through cytology), then your biggest concern should be the onset of an infection. You can prevent this from happening by putting some plain Neosporin on it and preventing your dog from licking it off. Not because ingestion of this is harmful, but because it won't do any good if it's licked off and bacteria from your dog's mouth gets on the wound.

You may need to have your dog wear an Elizabethan collar if your dog bothers it as that can predispose it to infection. See your vet if the area seems to smell bad, or shows signs of getting more inflamed or irritated. Unfortunately, cysts tend to seal over and refill once they rupture, only to rupture again at a later time. To be completely eradicated, the capsule may need to be surgically removed.

© 2013 Adrienne Farricelli


Mary Anne on April 25, 2018:

I have a standard poodle and my vet lanced one cyst 4 years ago and it's still open and leaking. It never healed. It is now growing what looks like large white heads. It smells of course. Just trying to keep it clean. Last year the vet said the dog was too old for surgery. Wish it had never been lanced.

Sue on October 23, 2017:

My yorkies has big cyst on his head by his left ear he keeps throwing his head backwards a lot any help as to why he doing this x

Adrienne Farricelli (author) on September 13, 2017:

Kelly, I would have the vet take a look at it to be sure. Your vet can then point to the right treatment.

Kelly on September 13, 2017:

Hi we have a sharpei that is 16 years old and she has this growth on her belly we just wondering is there an antiseptic that we can use to stop the smell as she has split it open and smell it like rotting flesh

Maryann on June 26, 2017:

We have a german shepard that gets the sebaceous cysts. A few years ago we had about 12 of them surgically removed. However the vet informed us that they would probably re-appear and sure enough did. I was brushing her recently and found two big ones that kind of grew into hard pieces that I removed. There is ugly stuff that can be squeezed out of them, which I prefer not to do. We have switched vets so I am going to see what this new vet view points are concerning these. I kind of look at these as acne and popping a pimple. They are gross.

Kelly on May 18, 2017:

My lil buddy has had two apprx pea sized sebaceous cysts on top of his head for about 6 years. We had them biopsied 3 seperate times (1st to find out what they were, 2nd when one split the first time, 3rd when I thought one was growing). All 3 times we were reassured. About 2 days ago i noticed a rough patch when petting his head, and noticed the bigger one has split open again and was oozing a bit of blood, but mainly a nasty looking whitish pus. I am SO weak in the tummy, but knew i had to do something so grabbed a clean cloth, qtips, gauze, alcohol, polysporin whatever i thought i may need, took a huge deep breath, and VERY lightly squeezed from underneath outwards, and expressed the contents of the cyst. Just typing this im fighting back my gag reflex... what came out was the most vile looking dark white, waxy like substance. To be honest I hurled... a few times. NOT for faint of heart, but he's my boy and it needed to be done.

** Note i did call the vet before i expressed and did a lot of internet research so i knew what to do.

After expressing it, i put some alcohol on to kill any bacteria, a TINY touch of polysporin (original regular) around the hole it expressed from, but not ON the hole itself as you want it open to be able to leak more if need be, dry out and heal better... clean 3x a day with warm soapy (regular soap nothing scented or anything like that, i use dove bar soap), and then i dab some alcohol on with a qtip and again polysporin around the hole. Its healing nicely :) it will likely refill in the next couple years for a do-over... but they are harmless. Just INCREDIBLY GROSS!!!

Adrienne Farricelli (author) on December 22, 2016:

All lumps should be checked out regardless of dog's age, size and whether it bothers the dog or not. It might not be an urgent ordeal to get checked tomorrow, but it's important to get them checked out as soon as possible..

miriam on December 21, 2016:

my dog is a mutt a chihuahua she is old and she has a lump by her nipple it was small but it grew a little bigger should I go and check it out? Also she doesn't mess with it ,it's like she really doesn't care for it. I also have another dog same breed a little younger she has 2 balls on her neck I feel like they are big.She scratches it sometimes with her leg nails.Should I check it out? Btw im 15 and idk how to get money for it my mother can not afford it so I don't know what to do.Please help

Aney on November 27, 2016:

My dogs cyst ruptured and I dont know what to do...Im scared to take him to the vet because of his temperament. Honestly freaking out a bit.

Adrienne Farricelli (author) on November 24, 2016:

Baby gates for when you cannot monitor.

Ron on November 22, 2016:

We have 2 American Cockers. Mocha, our 12 year old female is covered with them. We had several removed by the vet some years ago but it became apparent we couldn't keep up with them and they don't bother her. Our 5 year old male Dusty us just starting to develop a few small ones. He likes to lick his "sister's" sebaceous cysts though. That's kind of worrying. We can't watch the 2 of them 24/7

Adrienne Farricelli (author) on October 09, 2016:

Fay, please have your dog's lump checked out by your vet.

Fay on October 08, 2016:

My basset hound has had a lump come up between his toe it is red he won't let me near it I have put a sock over it to stop him licking it , he does not seem in pain .

Cheryl on August 01, 2016:

My dog has gotten a few of these. I've taken her to the vet, and even though she gets groomed regularly, theses cysts come on her side. When they have busted ooen, they are just gross, nasty. When cleaning the area with peroxide, wiping it, a sack pulls out and leaves a nasty hole. My vet has said, that sack must come out or infection starts. If you have a weak stomach, go to the vet. Me, I've done a few now and I clean it with warm water, apply neosporin 2x a day. So far, it's worked, but these things are nasty!

Norberto Moritz Koch on May 13, 2016:

Helps a lot, thanks.

Nancy Yager from Hamburg, New York on March 11, 2013:

They look like they must hurt to me. Poor things.