Sebaceous Cysts in Dogs

Sebaceous cysts in dogs occur when a pore or hair follicle gets clogged. This can happen because of dirt, infection, scar tissue or even normal sebum that becomes too thick to get out of the pore's opening. All pores and hair follicles in the skin are surrounded by microscopic oil glands. They're the glands that produce all the oil that makes our pet's hair (and our own hair) shiny, as well as make a protective and moisturizing layer for the hair and skin. The oil is called sebum.

Definition of Sebaceous

If the term 'sebaceous' sounds familiar to you, it may be because of the many times you heard it in your teen years as you were learning about acne and the oils in your skin. As long as these cysts are small and closed off from the outside air, it's fine for them to be left alone. They're harmless. Usually in the beginning stage they stay white, raised and small. When touched, your dog's cyst will feel like a small, circular or oval bump underneath the skin. They are very common with dogs, and are also called epidermoid cysts, epidermal inclusion cysts, epidermal cysts and wens. Normally your dog will ignore it and go about his or her daily life as if it wasn't there, and it will gradually get smaller until it goes away completely. If the cyst doesn't bother your dog, you might think of leaving it alone and waiting for it to heal on its own.


There is an exception to this, if the cyst is cut open or infected. Infection usually occurs because of the cyst being open, allowing bacteria to creep in. If this happens to your dog's cyst, then it's best to contact your veterinarian about antibiotics and topical cream. Sometimes even this doesn't help the cyst heal completely, and then all that's left to do is surgically remove it.

Sudden Growth

If the cyst suddenly grows very large in a few days, it's time to contact your vet. It could be sign of cancer or that it may be about to burst. A burst cyst is only a minor injury, but you really don't want your dog to lick and eat the goo. Some sebaceous cysts in dogs get so large that they need to be closed with a stitch. There is a chance that the cyst may be cancerous, and so your vet will take a biopsy of it with a needle. Treatment to cure it proceeds from there.


These cysts can also rupture underneath your dog's skin, spilling their oily contents into the area around the cyst. The end result is a highly inflamed area causing a red, itchy area that your dog is likely to lick, scratch and rub. These lesions can also be confused with a lick granuloma because both become inflamed and very itchy.

Although normally most sebaceous cysts are harmless, the option for treatment is up to you. The surgery needed to remove a cyst is usually short and uneventful, and shouldn't be too taxing on your dog.