What are cysts in dogs?
Cysts in dogs are common, benign (non-cancerous) growths that appear as lumps under the skin. They can vary in size and often contain a thick, yellowish or grey fluid. They are often found on the sides of the body, on the back near the tail, and the legs, but can potentially be found anywhere.
There are several types of cysts, including:
- hair follicular cysts
- sebaceous cysts
In most cases, the cause of cysts is unknown. But skin injury, infection, chronic inflammation from allergies and other skin conditions may result in a blockage and lead to a cyst forming.
Written by Dr. Mariella Roberts, Veterinary Surgeon, Animal Trust Vets CIC | Published June 2025 | Review date June 2027 | This advice is for UK pets only and is not a replacement for seeing a vet
Symptoms
one single or multiple round lumps in the skin
generally soft and squishy, but may be firm, depending on the content.
thick grey or yellow discharge
Cysts may become infected (especially sebaceous cysts)
Red skin or swelling around the cyst (inflamed/infected cysts)
When to contact your vet
If your dog shows any of the following signs:
excessive biting or licking at the area
red or swollen skin around the cyst
Discharge with a bad smell
change in the discharge from the cyst
Diagnosis
Ohysical examination by your vet
FNA test for cytology: a small needle is used to collect a sample from the lump
Surgical removal and histopathology: the lump may be sent to the lab following surgical removal
How to treat cysts in dogs
In general, cysts only require treatment if they are bothering your dog. Your vet might recommend one or more of the following, based on your dog’s specific needs:
home monitoring of cysts that do not cause discomfort and have not burst
topical antiseptics such as wipes, liquids or gels
oral antibiotics tablets or liquids by mouth may be prescribed in the case of larger, significantly infected ruptured cysts
surgical removal may be recommended for large cysts or those that cause discomfort for the pet
Prevention
There is no way of preventing cysts from developing, and these will often develop with age.
Although there is no sure way of preventing sebaceous cyst formation, the following can help to ensure that the skin is kept healthy and that problems are picked up at an early stage:
It is worth regularly inspecting your dog's skin for any new lumps or changes in existing ones
A balanced diet supports overall health, which can help maintain healthy skin
Exercise promotes healthy circulation and overall health, which can be beneficial for skin health
Regular grooming (particularly for long haired breeds)
Treatment and good control of any underlying health conditions which might impact skin health, such as an underactive thyroid.
Outlook
While cysts in dogs can be a cause for concern, they are benign and have a good outlook with timely treatment. Regular veterinary checkups and prompt treatment are crucial for ensuring the best possible outcome for your dog.