Sebaceous Cysts In Dogs And Cats

Sebaceous cysts are interesting structures.

All pores and hair follicles in the skin are surrounded by microscopic oil glands. These glands produce the oil that makes our pets’ hair (and our own hair) shiny, as well as producing a protective and moisturizing layer for the hair and skin. This oil is called sebum.

Sebaceous cysts occur when a normal pore or hair follicle becomes occluded. Occlusion can occur from dirt, infection, scar tissue or even normal sebum that becomes too thick to move out of the pore’s opening.

As long as the cysts are small, closed and intact they cause no problems.

Please do not squeeze them.

Sebaceous cysts become problematic when they burst and become open to the outside world again. Frequently then they become infected and must be removed surgically. Surgical removal becomes necessary when the cyst will not heal with topical and systemic antibiotics and/or irrigation.

Sebaceous cysts may also rupture under the skin and spill their oily contents into the surrounding tissues. The result is an intense inflammation causing a red, itchy area the pet is likely to lick, scratch and rub. These lesions may even be confused with a lick granuloma because both are highly inflamed and very itchy.

Early sebaceous cysts are usually white, raised and quiet-looking. As long as they stay in this phase they require no medical treatment.

It is when complications occur and they become inflamed that medical and/or surgical attention is needed for sebaceous cysts.

See you tomorrow, Dr. Randolph.

sebatious, sebacious


  1. So what happens if it pops on the inside. My 14 year old boxer had a sebaceous cyst on his right hip. It got quite hard at one time. Over the night at some point it had popped. Internally. Now he is very sic and deathly. Did his sickness come from the sebaceous cyst popping. I know he is old and I dont want him to suffer. Is it too late? Is it just his time? Would it be more proper if I were to have him put down? Please let me know. Thank you.

    • “So what happens if it pops on the inside?” The article says, “Sebaceous cysts may also rupture under the skin and spill their oily contents into the surrounding tissues. The result is an intense inflammation causing a red, itchy area the pet is likely to lick, scratch and rub. These lesions may even be confused with a lick granuloma because both are highly inflamed and very itchy.” I seriously doubt your pet is ill because of a sebaceous cyst rupturing. Please make an appointment with his veterinarian so that he can be evaluated. Thank you for reading, Dr. Randolph.

  2. Can you please help me? I have a female Chihuahua and she has a weird head coming out of her nipple she I’d in no pain the nipple is bruised but again she has no pain. What do I need to do ? She is normal other than that.

  3. My cat has a cyst on the back of his head, and after it grew to the size of a marble, it shrunk back to nothing. Weeks later it grew back, and starting leaking (mainly clear fluid, sometimes a little blood as he kept scratching), we finally managed to get a vets appointment who told us it was benign, just infected. We had a 5 day course of very strong antibiotics that cleared it up a bit, but not completely. The vets told us that since it’s not life threatening he won’t require surgery and because he’s 15, they wouldn’t risk surgery to remove it. The cyst starts to heal and close up, but he keeps catching it when grooming leading it to leak clear fluid occasionally. He won’t wear a cone and I fear even if he did, he’d just catch it again anyway. I’ve used a smidge of hydrogen peroxide in warm water to keep it clean, and it hasn’t stopped him eating or playing or being his normal self. Should I just keep clearing it this way, or are there any natural remedies to heal it a bit more? I don’t want him having a leaking head for the rest of his life lol. (The vets won’t give more antibiotics either).

      • My dog has a small bump on his leg that he keeps licking. It is not growing but he makes it nice and pink after licking. My vet want’s to remove it and send it out to test but it has not grown since I noticed 4 weeks ago. Is there anything I can put on it to keep him from licking it or do I need to keep a cone on for several weeks?

  4. I have a 2 yrs old lab, our first pet. She started her cycle on feb 13,2017 and finished the bleeding phase 21 days later. On day 22 I noticed some small cysts around her vagina, outside, in the edge and close to the tail. Apparently is not itchy or painful but the keep growing and appearing more and more, she started with one and now she has like 5. I that normal? I a litter concern about her. I am planning to take her to the vet to get her spayed.
    Please help me.. Thank you.

  5. My Japanese Spitz, Rupert, had/has a sebaceous cyst on his back under his tail. He cannot reach to scratch it which is great, and last June it popped and leaked keratin. Our vet cleaned it up and gave him some antibiotics and it scabbed over. 7 months later the scab remains! It’s very thick, but is obviously protecting the hole underneath. Is it normal for a scab to remain this long? He isn’t bothered by it one bit. Thanks 🙂

    • It’s also possible that what you’re seeing isn’t a scab, but, dried, caked sebum that has turned dark with exposure to air. As sebum is an oil product, it will also collect dirt, which can help it turn dark. Bottom line: it’s plugged up and keeping bacteria from invading into the oil gland and/or skin. If you must have a sebaceous cyst, a quiet one is the one to have! Thanks for reading

  6. I have sweet older kitty and I noticed a fluid filled lump under her skin. As I was feeling it, it seemed to drain when I squeezed it lightly or almost dissappear slowly. Now I can’t find it at all! I’m not sure if I should be concerned or what to do since I can’t find another spot like it. She doesn’t seem hurt and didn’t struggle or mind that I was inspecting it.

    • THE safest thing to do would be to have her seen. On the other hand, will the doctor be able to find anything? That’s an unknown, but, it’s not unusual that we can find things pet owners can’t. From that perspective, I would recommend having her examined. If you decide against an examination, be sure to watch for lethargy, loss of appetite, soreness in the general area where you found the lump, and fever. Best wishes, and thank you for reading

  7. Hello,
    Our labradoodle had a subcutaneous cyst that burst and leaked and bled for quite some time. We applied polysporin topically. It is now healed but the fur around the area has turned dark black (he is brown) and is no longer curly like the rest of his fur. Have you ever seen anything like that? Are colour changes worrisome?

    • Areas of skin inflammation often exhibit skin color change as the body puts pigment in the skin as a protective response. Hair color can change because of damage to the melanocytes, pigment-producing cells. Either can be temporary or permanent, but rarely are a medical concern. In older pets such changes bear watching by your veterinarian in case they are associated with malignancy. Thank you for reading

      • Dear Dr. Randolph,
        Scooter is my 18-year-old cat, A Russian Siberian, wonderful smart old guy. He has a ruptured cyst on his neck. He has had the cyst for years. I just noticed it is open with dry blood; but, less than a 1/2 diameter. He is eating and drinking. Tomorrow, I will take him to his vet. For tonight, can I put people-Neosporin on the wound?
        Thank you in advance for your thoughts.

  8. I have a question about my 7 yr old male ragdoll cat. I noticed a bump on the upper part of his stomach and it seemed like a scab put was poking out of his skin. I pulled it out to see what it was and it was hard at the top and then waxy on the end with hair on it…it keeps coming back slowly and this time I felt the bump underneath his skin so I squeezed it and a thick, waxy thing came out and seems to have hair stuck to it. I’ve done some research and cannot find any answers. the cat doesn’t seem to bothered when I touch it and it has never bled or been red. Do you have any suggestions? I will take him to the vet if necessary, just trying to avoid the crazy costs!
    thanks in advance

    • “Crazy costs?” Have you taken your child or yourself to see a physician lately? Veterinary medicine is the greatest healthcare bargain on the planet. If your pet isn’t bothered by the lesion it will probably be OK to have it looked at on your next regular visit. Thanks for reading

    • My cat has the same thing. He had a small lump, size of a nipple that slowly grew to the size of a xl large marble over 9 months. Yesterday it had a small area with what I thought was a head of an infection. It had never been never painful to him, so I scraped it and put pressure on it. He didn’t like it, howled a bit, but was fine the moment I stopped. First white and then gray very thick material came out. No blood or pus at all, actually nothing wet. Almost like gum or playdough. When I looked at it closer, it was hair compacted with a white stuff. He is grey, and the hair is identical. He has no pain or sensitivity at the spot, but there is still something left. I am afraid to keep squeezing it. But I also can not afford a vet trip. What happened with your cat?

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