All You Need to Know About Skin Cysts in Dogs

As tempting as it may be to pop them, don’t.

German Shepherds and Cocker Spaniels are just two breeds that tend to develop cysts. By: indichick

Does your dog suffer from skin cysts?

Or perhaps you’ve found a skin lump and you’re not sure if it’s a cyst or not.

Either way, I can help you understand what a cyst is, what to do about it and when to worry.


Every Cloud Has a Silver Lining

My morning got off to a sad start. The first patient of the day was an elderly Cocker Spaniel whose humans had decided it was time to say goodbye. But the second patient into the consulting room was the perfect pick-me-up: Ralph the German Shepherd.

Ralph is one of those bright-eyed, floppy-eared GSDs who uses his perky good looks to earn treats. His exuberant optimism was the perfect antidote to my morning of mourning.

Fortunately, Ralph’s problem was not serious. A cyst on his shoulder had burst, leaving a sticky mess in his fur. Ralph had had several cysts that popped from time to time. This time, the open wound had become infected, needing a cleanup and antibiotics.

What Is a Cyst?

Cysts tend to occur in middle-aged or older dogs and are most commonly linked to breeds such as German Shepherds, boxers, and Cocker Spaniels.

Technically speaking, a cyst is a sac in the skin lined with secretory cells. Fluid builds up inside the sac, causing a swelling on the surface of the skin. Some cysts stay fluid, while for others, over time, the liquid dries out, leaving a firmer, cheese-like material inside.

Are Cysts Dangerous?


The biggest risk from cysts is that the lump is mistakenly diagnosed as a cyst when in fact it is a tumor. To avoid this, most vets will pop a fine needle into the lump and suck back on the syringe. A cyst should yield a small sample of the inner core, which is an easy way to confirm the diagnosis.


Other signs that the lump could be a cyst include:

  • The lump has a round shape.
  • The lump has distinct edges and you can feel all the way round it.
  • It’s superficial, meaning you can lift the cyst up and away from the underlying tissues.
  • It’s not itchy (itchiness can be a sign of a particular aggressive type of skin tumor).
  • It’s slow to grow.

That said, it’s always best to get any new lump checked out by a vet. Also, measure and record the size of the lump, and take photos on your smartphone so you or your vet can see if the lump is enlarging or not.

Cysts aren’t generally dangerous for dogs, but if they get infected, it’s time to see the veterinarian. By: s2ublack

What Does a Skin Cyst Look Like?

Skin cysts are round nodules that sit on the skin’s surface or just below the surface. They feel round and are either soft or filled with fluid. Those on the surface are often bald and associated with a patch of hair loss.

As the pressure builds up inside the cyst, sometimes a weak spot develops. Then, if the cyst is knocked, it may burst with the fluid leaking out through that weak point. The contents of a cyst vary widely depending on the type, from a clear, straw-colored liquid to an ash-colored, cheese-like material. Ralph’s cyst was of the latter sort but had developed a secondary infection.

How to Treat a Dog’s Skin Cyst

If the vet is happy the lump is a cyst, then there’s no urgency to remove it.

Indications for removal include:

  • Cysts that get caught under a collar or harness, or are damaged when the dog is brushed
  • A burst cyst that is infected and doesn’t respond to antibiotics

Surgical removal is a relatively simple procedure, depending on location. Surgery can often be done under sedation and local anesthetic when access to the cyst is easy.

Resist the Urge to Pop It

Squeezing a cyst can force the contents into the surrounding tissue, where it sets up a foreign body reaction, resulting in swelling and inflammation.

If, however, the cyst ruptures (which happens from time to time), trim the hair away and wash the area with weak saltwater. Gently milk out the remainder of the cyst contents and monitor the hole for signs of infection, such as a smelly, yellow-green discharge.

The pleasing thing about a freshly burst cyst is that the lump disappears for a while. But this is only a temporary, since the lining is still present and capable of secreting more material. This means once the skin heals over, the cyst will slowly refill, like a plugged sink with the tap dripping.

Happily, I anticipate Ralph’s infected cyst will heal and not cause any problems…until the next time it bursts.


This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Oct. 11, 2018.


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