What is a sebaceous cyst?
A sebaceous cyst, also known as an epidermal cyst, is a lump that develops beneath the skin. Sebaceous cysts form inside the sebaceous glands, which secrete an oily substance called sebum to lubricate the skin and hair. The cysts develop when the gland or duct becomes blocked, and sebum builds up inside the gland and forms a soft lump under the skin.
Sebaceous cysts typically feel smooth and soft and can form anywhere on a dog’s body where there are hair follicles and sebaceous glands, including the head, neck, trunk, and extremities. The cysts can range in size from a few millimeters to a few centimeters across. Often the lump can be moved freely underneath the skin and is not painful unless it becomes irritated.
The contents of a sebaceous cyst are greasy and cheese-like. The cyst is surrounded by a layer of epithelial cells and contains sebum and cellular debris. Normally sebaceous cysts are harmless and often do not require treatment. However, they can sometimes become red, inflamed, and painful if they rupture or become infected.
Common locations
Sebaceous cysts can pop up anywhere on a dog’s body, but there are certain spots where they are most frequently found. Here are the areas where sebaceous cysts commonly occur on dogs:
Head – The head is a very common place for sebaceous cysts to develop on dogs. They often form on the forehead, cheeks, and around the ears. The high concentration of oil glands in the facial area makes dogs prone to cysts in this region.
Neck and shoulders – The neck and shoulders are another typical hotspot. These areas often rub against collars or get scratched by a dog’s paws, which can trigger cysts.
Chest and abdomen – A dog’s underside, including the chest and belly, frequently sprouts sebaceous cysts. These areas collect moisture and rub against surfaces regularly.
Legs – Sebaceous cysts commonly show up on dogs’ legs as well. They can form anywhere from the thighs down to the paws. Friction from walking likely contributes to cysts on the legs.
Back – Dogs’ backs also provide a prime spot for sebaceous cysts. Pressure from lying down combined with dirt from the ground facilitates cyst formation on the back.
Tail and rear – Finally, the base of the tail and rear end is another area prone to cysts. Again, moisture and friction against sitting surfaces makes this zone a cyst hotspot.
Causes
Sebaceous cysts form when the sebaceous glands in the skin become blocked. The sebaceous glands produce sebum, an oily substance that lubricates the skin and hair. When these glands get obstructed, the sebum gets trapped beneath the skin and forms a cystic mass or lump [1].
There are several potential causes of sebaceous gland blockages that can lead to cyst formation in dogs:
- Genetics – Some dog breeds are genetically prone to developing sebaceous cysts, including Cocker Spaniels, Poodles, and Schnauzers [2].
- Inflammation – Inflammation around a sebaceous gland can cause blockage and cyst development.
- Trauma – An injury that damages a sebaceous gland may trigger cyst formation.
- Infection – Bacterial or fungal infections can cause cysts.
- Allergies – Allergic reactions may inflame sebaceous glands and lead to cysts.
- Hormones – Hormonal imbalances can overstimulate sebaceous glands.
In some cases, the exact cause of a sebaceous cyst cannot be identified. But most often, they result from blocked sebaceous glands in the skin.
Symptoms
Sebaceous cysts are usually not painful, but you may notice the cyst if it becomes large. Some of the common signs of a sebaceous cyst in dogs include:
- A raised bump under the skin, ranging in size from a pea to a few inches across. The cyst may feel firm or spongy.
- A smooth dome shape, although the surface may become misshapen over time.
- A bluish color under the skin, but the surface layer appears normal.
- No hair growth directly over the cyst.
- Appearing most often on the head, back, or trunk area.
- A thick, cheese-like substance draining from an ulcerated cyst.
- Swelling, redness, and pain if the cyst becomes infected or ruptured.
Sebaceous cysts are typically round and moveable under the skin. They are often easy for a vet to diagnose by look and feel alone. Refer to pictures of sebaceous cysts in dogs to compare against any questionable lumps on your dog. If you notice symptoms of an infected cyst like swelling, redness, and pain, contact your vet right away as antibiotics may be required (Kingsdale).
Diagnosis
To diagnose a sebaceous cyst, the vet will first do a physical exam of your dog. They will look for signs like a raised lump under your dog’s skin that may have a bluish color. The vet will also check if the lump moves easily under the skin when touched.
Your vet may then use a fine needle to draw fluid from the lump. This is called a fine needle aspiration. They will look at the fluid under a microscope for signs of a sebaceous cyst, like fat cells or keratin debris. This test can help rule out other kinds of lumps.
In some cases, a biopsy may be done. This involves surgically removing all or part of the lump and sending it to a lab for further testing. The lab results will confirm if the lump is a sebaceous cyst.
Diagnostic imaging like x-rays or ultrasound may also be used. This gives the vet a better view of the size and location of the cyst. It also helps determine if the cyst is affecting other structures.
Treatment
There are several ways sebaceous cysts in dogs can be treated, including draining, removal, and home remedies. Draining the cyst is one common treatment, which involves puncturing the cyst with a sterile needle and draining the fluid contents. This helps relieve pressure and discomfort but does not remove the cyst sac itself, meaning the cyst may refill over time. Surgical removal is considered the most effective treatment, as it fully removes the entire cyst and prevents recurrence. This is done under general anesthesia, with the cyst carefully dissected out without rupturing it. The area is then closed with sutures or staples.
According to Kingsdale Veterinary Hospital[1], surgical removal provides a definitive solution, but may not be practical if the dog has numerous cysts. As an alternative, some veterinarians may opt to freeze or cauterize the cysts instead of surgically removing each one. Home care after surgical removal involves keeping the area clean and preventing licking or biting at the incision site while it heals.
There are also some home remedies and over-the-counter options owners can try, such as applying a warm compress or ichthammol ointment to help soften and drain cysts. However, these do not provide definitive treatment. It’s important to have any rapidly growing, ulcerated, or easily traumatized cysts evaluated by a vet rather than attempting to treat these at home.
[1] https://www.kingsdale.com/sebaceous-cysts-in-dogs/
Home Remedies
There are several natural and home treatment options for sebaceous cysts in dogs that may help manage them without surgery. Some popular home remedies include:
Warm compresses – Applying a warm, wet cloth or compress to the cyst can help promote drainage and healing. Do this several times a day for 10-15 minutes at a time. Be sure to use a clean cloth each time.[1]
Castor oil – Apply a small amount of castor oil to the cyst and massage it in gently. Castor oil has anti-inflammatory properties that may reduce swelling and irritation. Use several times per day.[1]
Turmeric – Turmeric contains curcumin which has antioxidant and anti-inflammatory effects. Mix turmeric powder with water to make a paste and apply it to the cyst. Rinse off after 15-20 minutes.[2]
Coconut oil – The lauric acid in coconut oil has antimicrobial properties. Gently rub a small amount of extra virgin coconut oil on the cyst 2-3 times per day after cleaning the area.
While home remedies may help manage sebaceous cysts, it’s important to have any cysts checked by a veterinarian, as some may require medical treatment or surgical removal. Never attempt to drain or lance a cyst at home.
Prevention
There are a few ways to help prevent sebaceous cysts from developing in dogs:
Regular brushing and grooming can help unclog hair follicles and sebaceous glands, allowing them to function normally. This helps prevent blockages that can lead to cysts (Source). Brush your dog’s coat thoroughly at least once a week.
Avoid shaving double-coated dog breeds like Siberian Huskies as this can stimulate sebaceous glands and increase cyst risk (Source).
Feeding a high quality diet rich in omega fatty acids can help keep your dog’s skin and coat healthy. Talk to your vet about supplementing with fish oil if needed.
Keep your dog at a healthy weight, as obesity may increase sebaceous gland stimulation.
Clean any existing cysts gently with an antiseptic wash to prevent infection. Do not try to rupture or drain cysts at home.
Risks
Sebaceous cysts can become problematic if left untreated. Potential complications include:
Rupture – Sebaceous cysts can rupture and drain fluid onto the skin. This can lead to infection and inflammation. According to Kingsdale, ruptured cysts should be treated by a veterinarian to prevent further complications.
Abscess – Ruptured cysts are prone to abscess formation, which is an accumulation of pus. Abscesses are painful and require drainage and antibiotics, per VCA Hospitals.
Infection – Bacteria can enter a ruptured cyst and cause infection. Signs include redness, swelling, pain, and pus. Infections must be treated with antibiotics.
Recurrence – Sebaceous cysts often recur if not completely removed. The cyst wall must be fully excised during surgery to prevent regrowth.
Interference – Large or problematic cysts may interfere with movement or normal functions. Surgery is recommended in these cases.
Spreading – Occasionally, multiple cysts may develop if one ruptures and spreads infected material. Regular monitoring is important.
When to see a vet
Most sebaceous cysts in dogs are benign and don’t require veterinary treatment. However, there are some signs that indicate a cyst should be evaluated by a vet:
According to Kingsdale Veterinary Hospital, you should take your dog to the vet if the cyst is red, inflamed, or showing signs of infection, such as pus or a foul odor [1]. An infected cyst can spread bacteria internally and make your dog very ill.
You should also see your vet if the cyst ruptures, as noted by Wag Walking. Ruptured cysts are at high risk for infection and need to be treated right away [2].
Additionally, veterinary evaluation is recommended if the cyst is rapidly growing, bleeding, or bothering your dog. Your vet can provide treatment options to resolve these issues.
Finally, ToeGrips says recurrent cysts or cysts that don’t respond to home treatment warrant a vet visit to explore underlying causes and surgical removal if necessary [3].
