Treating Canine Comedones

Sandra writes: “But what if my dog has small ones [sebaceous cysts] that kind of pop up like black dots? I gently squeeze them, the contents come out and his skin heals just fine. Is that ok? It’s pretty much like popping a human pimple.

Just can’t resist them, can you, Sandra?

Schnauzers are the breed most likely to be affected with comedones.
Schnauzers are the breed most likely to be affected with comedones.

I know it’s tempting. Unlike Nike, though, I’m going to ask you to Just NOT Do It.

There is a big difference between sebaceous cysts of dogs and pimples in people. Pimples are almost immediately colonized by the bacterium Propionibacterium acnes.

“Healthy” sebaceous cysts in dogs and cats are sterile, totally lacking in bacterial population. The biggest cause of complications with sebaceous cysts, and the most likely factor to cause them to need surgical excision, is infection. As long as they are sealed from the outside they usually don’t become infected. If they aren’t infected they don’t cause problems unless they become excessively large.

The latter problem is rare.

The former problem can be avoided by leaving them alone.

If you can.

It is also possible that what Sandra’s dog has is not a sebaceous cyst at all, but a comedo. These are most likely to appear in miniature Schnauzers, but can occur in any breed or individual.

A comedo is similar to a pimple, in that it is a collection of oily material in a pore. It is black because of exposure to oxygen and accumulation of debris. Comedones are best emptied by use of benzoyl peroxide shampoos, which have “follicular flushing action,” the ability to go down inside pores and hair follicles and remove foreign material.

Click here for instructions on proper use of medicated shampoos. Of course, as always, follow your pet’s doctor’s advice if it conflicts with ours.

See you tomorrow, Dr. Randolph


  1. My dog has developed what looks like a blackhead inside the nipple. There is a small hole on the surface making it look like it’s ready to be squeezed out any second. She’s not in an sort of pain but she’s never had puppies before for it to be a clogged duct. It appears to be a small black hard round blackhead that’s just waiting to wiggle out. Any idea what it could be?

  2. My dog also had a sort of a “cyst” for a while, then today I went to look at it and it had turned black. When I started touching it, it started oozing out some black stuff. She seemed like she was in a little bit of pain. What might that be? I am kind of worried after reading that cysts should be left alone, but I am not sure if it was really a cyst or something else. At first, it was just a bump (no specific color, just on her torso right under the fur). Should I be concerned about it?

    • Naya, what it could be would take hours to list, but your pet’s doctor should be able to give you at least an opinion if not an outright diagnosis with an examination. Do that, and you have the peace of mind of knowing whether it’s something that needs to have surgical removal right away, or can simply be monitored for changes. Let us know how it turns out. Best wishes, Dr. Randolph.

  3. They are black on the outside, and hard. Underneath there is usually some white material; how much depends on the size of the thing itself, but it’s never been anything as gross as the stuff you find in youtube. My dog is not a particular breed, since he’s a rescue and we have no idea what his actual lineage is, but he looks like he could have some Pitbull in him. He’s had several of these things, more than 5, spread between his back, torso and neck. They have never become infected but, of course, I disinfect the wound after and he doesn’t get to roll over dirt surfaces. Thank you for the advice.

      • I have a 12 yr old short hair dachshund. Our vet dx is Comedones – blackheads. She keeps getting reoccurring cyst on the same back leg. Our vet recommended we start giving her Purina Pro Plan Veterinary Diets FortiFlora Probiotic – Omega supplement Free Form Snip Tips Fatty Acid Capsules for Small Dogs & Cats,
        Benzyl Benzoate acne wipes and EnteDerm Ointment . She has been on for almost 2 months.. She keeps getting the cyst…. Tons of black heads underneath the skin – her vet said. Surgery is an option but with her age we would rather not do surgery… found info on line about Aesculight CO2 Laser treatment.. My vet does not have this laser – but recommended a place that has the Aesculight CO2 Laser.. Do you have any recommendations ??
        was thinking of getting good grooming shampoo first, removing dirt and excess oils that interfere with medicated shampoo action. do you have a good recommendation for grooming shampoo and medicated shampoo – Greatly appreciate your help

        • We use a grooming shampoo called Butler Cherry, however, unless your pet’s doctor does business with Covetrus, a distributor, he may not have access to it. Ask his recommendation for an alternative, if he doesn’t. You could also ask him if a referral to a board-certified dermatologist might be helpful. Thanks for reading, Dr. Randolph.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.