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Hygroma:

A Definitive Guide

Dr. Sarah Wooten

Veterinarian

Learn about Dr. Wooten

Hi there! You have likely found and are reading this comprehensive guide about hygromas for one of three reasons:

1. You were petting your dog and noticed a swelling under the skin, most likely on or near the elbow or hip, or another bony part of your dog. You quickly searched ‘dog elbow swelling’ and came up with something fancy called ‘hygroma’.

2. You have been to the veterinarian recently and your dog was diagnosed with a hygroma.

3. You have heard about hygromas, know a dog that has a hygroma, or have a big dog yourself and DON’T want your dog to develop a hygroma.

Sound about right?

If so, you’re in the right place. This definitive guide on hygromas will provide all the information you’ll need to address all three possibilities listed above. It is written by a real veterinarian who spent 16 years in clinical practice helping dog lovers just like you. By the end of this guide, you will be armed with the information you need to:

1. Help a dog that already has a hygroma

2. Understand the available treatment options for a hygroma

3. Implement strategies to reduce your dog’s likelihood of developing a hygroma

         

Sound good? Let's get started!

TABLE OF CONTENTS

1. Definition of a Hygroma

2. Signs and Symptoms

3. Causes of Hygroma

4. What to Expect at the Veterinary Office

5. How to Treat a Hygroma

            a. Home Treatment

            b. Medical Intervention

            c. Surgical Options

6. How to Prevent a Hygroma and Factors to Consider

            a. How much does your dog weigh?

            b. Where does your dog sleep?

            c. How's your dog's health?

7. Glossary of Terms

1. Definition of a Hygroma

A hygroma, or a false bursa, is defined as a fluid-filled swelling that develops under the skin. This fluid-filled capsule is enclosed within a thick layer of fibrous tissue - think of it as a water balloon that is surrounded by a tough, flexible material. A hygroma forms in response to repeated pressure trauma to tissue, like when a dog repeatedly sleeps or lies down on a hard surface.

2. Signs and Symptoms

Hygromas are usually located over any part of a dog’s body that is bony and sticks out. This includes the side of the ankle joint (otherwise known as a hock), the side of a hip or the side or underside of an elbow. They are most commonly found on the elbow, though they may also be located over the point of the hip, in which case they are called ischial hygromas.

When a hygroma first appears, they are usually small, soft, and can be easily moved around under the skin. A hygroma may be so small that you may not even notice it, and the only way it is detected is by your veterinarian while she is conducting an exam. If a hygroma grows larger, it may become hard and bothersome to your dog.

Image provided by Wikipedia

Hygromas usually do not hurt, unless they are so large that the dog cannot rest on the affected area, or if they become infected. An infected hygroma looks angry: it can be red, swollen, warm or painful to the touch and may weep or leak fluid.

Hygromas often appear on both elbows at the same time. If a dog has had a hygroma for a long time, there is a risk of severe inflammation. This inflammation can result in ulceration of the skin over the hygroma, development of a chronic draining wound or erosion of the surrounding tissues. Furunculosis, a deep bacterial skin infection caused by infected hair follicles often associated with hygromas. Comedones (black heads) are also common.

Is a Callus a Precursor to a Hygroma?

A callus is an area of thickened skin that develops in response to repeated pressure trauma. Calluses are often hairless, and can become irritated and red. A callus is not necessarily a precursor to the development of a hygroma. But, if you see a callus, it’s a sign that your dog is lying on hard surfaces too often, and you need to provide softer surfaces for your dog to rest upon. Calluses can be treated by applying an emollient lotion, like The Blissful Dog's Elbow Butter, which can soften the skin. If you are concerned that your dog has a callus that is irritating, please consult with your local veterinarian.

3. Causes of Hygroma

Hygromas occur when the tissue (fascia, muscle, etc.) overlying a bone is repeatedly traumatized. Trauma to this tissue occurs when large or giant breed dogs repeatedly lie down on hard surfaces, such as tile, hardwood floors or concrete. This is why the elbow is the most common site for a hygroma to occur - if a large breed dog is lying down on a hard surface, there is no way to avoid the pressure trauma to the elbow.

Here’s what a common hygroma may look like:

Dogs are not supposed to lie down continuously on hard surfaces because it creates pressure trauma in the tissues that overlie the bony parts. When the body’s tissues are repeatedly exposed to a pressure trauma, it induces an inflammatory response in the tissues under the skin. This is the body trying to protect itself from the pressure trauma, by creating a hygroma that acts like a ‘pillow’ to cushion the skin. If the dog continues to lie on hard surfaces, the hygroma will only grow larger.

Hygromas are more common in dogs that spend a lot of time lying down. If your dog is older, has arthritis or other health challenges that cause him or her to be less active, then your dog is at increased risk of developing a hygroma on the elbow.

Hygromas can also be an issue among younger dogs (usually between 6 and 18 months) who are prone to flopping down onto hard surfaces. Young large breed dogs that lie down on hard surfaces should be given a soft place to rest to reduce the risk of developing a hygroma.

The good news is that a hygroma is not a tumor, is not cancerous, and has no risk of spreading to other areas of the body.

4. What to Expect at the Veterinary Office

If you think your dog has a hygroma, you definitely need to get your dog checked out by a veterinarian. Your veterinarian will be the best resource to guide you through your options, and your veterinarian can also ensure that the swelling isn’t something else, such as a tumor or an infection. At the veterinary office, the staff will weigh your dog and take vitals. They will ask you questions about your dog’s daily routine, where he or she sleeps, how active your dog is, if your dog has any other medical problems, if your dog on any medications, etc. Try to be as specific as possible in your answers. It may help to write down your answers to those questions beforehand so you don’t forget any important information.

The veterinarian will conduct a complete physical exam. That means that she or he won’t just check the elbow, everything else on your dog will be checked as well! Since hygromas are usually seen in dogs that sleep or lie down more than usual, it is important to determine the reason why your dog is lying down so much. Health issues ranging from arthritis to heart disease and even hormonal disorders can cause excessive tiredness in dogs, and your veterinarian is the best one to figure that out, if needed.

If your veterinarian suspects any additional problems outside of the hygroma, she or he may recommend laboratory testing or imaging, such as an x-ray or ultrasound. Follow all recommendations from your veterinarian. If your veterinarian finds additional issues that are causing your dog to lie down or sleep more than usual, it’s important to work with your veterinarian to resolve those issues, in addition to treating the hygroma.

5. How to Treat a Hygroma

Home Treatment Options:

When it comes to treating the hygroma itself, the most important consideration is to prevent further pressure trauma by providing a well-padded surface for your dog to rest upon. Providing a high quality bed with durable and supportive padding is essential for dogs with hygromas because it will cushion their joints from the hard surfaces while they rest for long periods.

If you need to cushion a larger area, you can put down foam interlocking tiles, like what you might use as home gym flooring. These tiles can be found at big box retailers and online on sites like Amazon. There are also commercially available protective elbow pads specifically designed for dogs with hygromas that your dog can wear. Padded surfaces to rest upon is the single most important treatment to keep a hygroma from getting worse.

Medical Intervention Options:

Over time, usually about 3-4 weeks, an uninfected small or medium-sized hygroma may resolve on its own with proper padding and protection. Your veterinarian may also elect to drain the hygroma with a needle and may recommend photobiomodulation therapy with a therapy laser to speed healing. If these therapies are combined with appropriate padding and a supportive sleeping surface at home, this treatment often resolves small hygromas without the need for surgery.

Here’s an example of a laser therapy treatment:

If a hygroma becomes infected, it must be treated with antibiotic therapy, usually for a period of several weeks. It is important to be patient and continue antibiotics until they are finished to resolve the infection and prevent reinfection.

Surgical Options:

If a hygroma is large, it can be drained or removed surgically, but unless the underlying cause is addressed (sleeping or lying down on a hard surface), the hygroma will come back or worsen. Before your dog has surgery, be sure to have an appropriately padded surface for your dog to lie down and sleep comfortably on after surgery.

One treatment of hygromas is surgical drainage. If this treatment is chosen, your dog will be admitted for outpatient surgery. Your dog will be either sedated or anesthetized, and Penrose drains will be surgically placed in the hygroma. These drains will be left in place for several weeks, and you will be required to change and monitor the bandages on the wound. After several weeks, the hygroma should be dry, and the drains will be removed during an outpatient appointment.

If surgical removal is recommended for a hygroma that is large, painful or chronically infected, it is very important to work with your veterinarian to keep the elbow properly padded while healing from surgery, and to give all medications as prescribed. It is also important to follow post-surgical activity rules - if a dog is too active after surgery, swelling and irritation can develop at the surgical site. The surgical site can also open up, which may require skin grafts or repeated surgeries, so the importance of keeping your dog relaxed after surgery cannot be stated enough. If your dog has a lot of energy or is difficult to keep in a restful state, talk with your veterinarian about using a sedative after surgery to facilitate healing.

Make sure your dog wears a cone or bite not collar to prevent licking or chewing at the surgical site or Penrose drains. If your dog licks the wound, it can become infected, the Penrose drains can be ripped out prematurely or the sutures may fall out prematurely, all of which will require veterinary attention and possibly more surgery. Dogs will usually leave a surgical site alone if it doesn’t hurt, so make sure to give all pain medication as prescribed. If you see your dog trying to lick or chew at the surgery site, call your veterinarian immediately.

Dogs will usually leave a surgical site alone if it doesn’t hurt, so make sure to give all pain medication as prescribed. If you see your dog trying to lick or chew at the surgery site, call your veterinarian immediately.

6. How to Prevent a Hygroma and Factors to Consider

You may be asking yourself at this point, “Hygromas are a pain. Is it possible to keep my dog from getting one altogether?”

The answer is YES!

There are three main factors to consider if you want to prevent your dog from suffering from a hygroma:

How Much Does Your Dog Weigh?

The first factor to consider is your dog’s weight. Overweight and obese dogs are at a much higher risk of developing a hygroma than dogs with a normal body weight. Think about it this way: the extra weight puts more pressure on the tissue overlying the bony parts of a dog and a fat dog will lie down more. It’s a vicious cycle that needs to be avoided completely.

If your dog is overweight, ask your veterinarian about an ideal weight for your dog, recommendations for how much to feed them and the best food to facilitate rapid weight loss.

Where Does Your Dog Sleep?

The second most important factor to consider is where your dog sleeps. Be sure to provide a supportive sleeping surface that cushions any at-risk bony body parts from the hard floor and make sure anything your dog lies down on is cushioned. If you notice your dog is seeking hard floors, like tile, because they are cooler, you may need to install air conditioning or bar access to hard floors with the use of baby gates.

How’s Your Dog’s Health?

The third factor to address is why your dog is lying down more. Arthritic dogs will lie down more if they are in pain. If your dog is arthritic, talk with your veterinarian about pain management. If your dog is lying down more because they’re hot, consider getting your dog shaved for summer or provide a kiddie pool for your dog to lounge in. Does your dog have other health challenges? Get them addressed. The sooner you do, the better quality of life your dog will have and the lower the likelihood that a hygroma will develop.

By addressing these three factors, you will greatly reduce the likelihood that your dog will develop a hygroma.

7. Glossary of Terms

Bite Not Collar: A bite not collar can be a great alternative to the Elizabethan collar, particularly if your dog is uncomfortable or on edge in a typical “cone” collar. Because the Bite Not collar is rigid, the dog is unable to turn their head from side to side, which prevents them from licking or chewing at their surgery site.

Furunculosis: A deep infection of a hair follicle that can lead to abscess formation.

Hygroma: Also known as a false bursa, a hygroma is a fluid-filled sac that forms on a dog’s bony protuberances (primarily elbows and sit bones) due to repeated pressure trauma which is most often caused by lying on hard surfaces.

Penrose Drains: Penrose drains are used to drain surgical sites more easily after an operation and are made of soft and flexible rubber tubing. Penrose drains keep the area from accumulating liquid and reduces the chance of bacterial infections.

Photobiomodulation therapy: Also known as PBMT or Low Level Laser Therapy (LLLT), this light therapy uses lasers or LEDs to improve tissue repair, reduce pain and inflammation wherever the beam is applied.

Pressure trauma: Caused by localized and repeated damage to the skin and underlying soft tissue over a bony prominence, particularly elbows.