Burst or Ruptured Cysts on Dogs: Our Vet Explains (With Pictures)

This article was updated on October 1st, 2023

While I see a large number of cysts on my patients, it is not that common to see a ruptured cyst. This is likely due to the fact that most cysts remain small and they can have quite a robust shell or wall.

When a dog does come into my clinic with a ruptured cyst, the owner can be quite alarmed by the gunk and discharge they’ve seen! It is usually a sebaceous cyst that bursts, and the insides can be a grey or white liquid and can even look a bit like cottage cheese.

While there will be some mild discomfort, most dogs cope well with burst cysts. Thankfully, they tend to be easy to treat and most cysts are well on their way to being healed within a few days of starting treatment. In this article, we will review what ruptured cysts look like (with pictures of ruptured or burst cysts), and what to do.

Why do cysts burst or rupture?

Cysts can rupture after developing an infection, as the increased amount of pus or white cells puts pressure on the cyst wall. We can also see burst cysts after a trauma, such as a sharp scratch from the dog or a nip from one of their doggy playmates.

What do ruptured or burst cysts look like? (with pictures)

In the following image, we can see a sebaceous cyst, which has become very red and inflamed. We can see that ‘cottage cheese’ material, which is made from sebum. This cyst will have formed when the gland became blocked or damaged for whatever reason. Some dogs are more prone to them than others, with Spaniels and Schnauzers being overrepresented.

The next image is a ruptured follicular cyst, which is bleeding quite a lot. These cysts originate within the hair follicle and can cause quite large and raised lesions on the skin. While the discharge in this dog’s cyst is very bloody, we can also see clear, grey or yellow ooze.

Below is an image showing a cyst before and after rupture:

An opened cyst on a golden retriever:

This fourth image below is a true cyst, which will contain a clear or transparent fluid. These cysts often form within the sweat glands, and we frequently see them on eyelids. These lesions usually form nodules and are see through, blue or dark.

Does a burst or ruptured cyst on a dog need to be treated or can it be left alone?

While we often take a ‘wait and see’ approach with a cyst, if it has burst or ruptured, it does require medical care. Importantly, owners should resist the temptation to squeeze or pick at a cyst. This can introduce infection and may do more harm than good. Book your dog in to see their vet, so we can get the cyst cleaned up and treated.

How can I help my dog at home?

From home, prevent any licking or chewing. This may mean using a buster collar or putting a loose, cotton t-shirt on your pooch. We want to avoid bandaging the cyst, as this can increase humidity and lead to bacterial proliferation.

If the fur around the cyst is getting wet or matted from the discharge, we can trim it with a scissors. The more ventilation around the cyst, the better. Don’t be tempted to apply any human or OTC creams to the cyst, as they’re generally not tolerated by dogs and may make them want to rub or lick the lesion more.

Can I pop my dog’s cyst from home?

It might be hard to resist squeezing a cyst, especially if you’re curious to know what is inside or if it has recently gotten quite large. However, it is important to resist the temptation. Popping cysts can introduce infection and may be uncomfortable for your dog.

As popping the cyst does not affect the cyst wall, even if all of the contents are squeezed out, the cyst will still re-fill and quickly come back.

Is a ruptured or burst cyst a reason to visit your veterinarian?

Though a burst cyst isn’t reason for high-tailing it to the nearest emergency clinic, you should book an appointment promptly, so the cyst can be dealt with before it worsens.

At the clinic, your vet will determine if your dog’s lesion really is a cyst and will check for signs of infection. They may drain any remaining cyst contents and flush out debris or dirt. If there are signs of infection, your dog will likely be started on a course of antibiotics.

Are there over-the-counter medication that can help?

Good old salt water really is your friend here, and it can be applied to the cyst using cotton wool. Clean away as much of the ooze as you can, being gentle as your dog may be very sensitive in this area. You should reward your dog with lots of praise and a treat after the cyst has been cleaned.

To make salt water, simply add a tablespoon of table salt to a mug of boiling water, stir and allow it to cool before using. You can also use antiseptics such as a medicated antiseptic spray, to protect the open cyst from developing an infection until you can reach the vet.

If needed, use a buster collar to protect the cyst as if your dog is managing to lick or chew it, this will be introducing a huge number of pathogens. A soft, fabric collar is often best tolerated.

How will my vet treat the cyst?

How the vet will want to treat your dog’s cyst will depend on type of cyst, its size and where it is located. For example, a cyst on the eyelid is often scratching the surface of the eye and causing ongoing infections and ulcers. In these cases, surgical removal is advised.

In cases where a cyst is small and in an area unlikely to bother the dog (such as on its back), the ruptured cyst may be treated with a course of medicine and then be allowed to re-form. If, however, the cyst continues to rupture and cause issues, the vet would then consider surgical removal.

When surgery is performed, the aim is to remove the entire cyst wall so that the cyst will not re-form and is gone forever. Ideally, the removed cyst would be sent to the lab for histopathology, so the vet can confirm that it is indeed a cyst and that it has been completely removed.

Uncommonly, the lab will diagnose a cyst cancer called a sebaceous gland adenocarcinoma. It is important to know if this is what was removed from your dog, so your vet can check for any signs of cancer spread.

Will a ruptured cyst heal on its own? How long will it take to heal?

In the absence of an infection, these cysts can seal over and heal rapidly. A dog who is young and in good health will heal quicker when compared to a senior who has ongoing health issues such as endocrine disorders or chronic infections.

A small cyst may heal in a matter of days, while a longer one could take weeks. If the cyst is infected, this will slow down the healing process and the cyst won’t fully heal until the infection has gone.

Can I prevent my dog from getting cysts?

Some dogs are just genetically prone to getting cysts and there’s not much we can do to stop this. However, it can help to groom your dog regularly, to ensure their natural oils are being spread along their fur and to prevent fur mats. This also provides the perfect opportunity to check your dog over for any early cysts or masses.

It’s a really good idea to check your dog’s skin regularly and to make note of any new growths. A new cyst can be photographed beside a coin, so you can monitor its progress and show it to the vet.

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