Many pets — from dogs, to cats and even rats — are prone to developing sebaceous cysts. These cysts are filled with a white toothpaste-like paste known as sebum. Sebum is a natural oil that’s produced by the skin. It serves to keep the skin moisturized and smooth.
Unfortunately, sebum can cause a cyst when it gets trapped inside a hair follicle or pore. Sebaceous cysts can get quite large — the size of a nickel or larger — resulting in pain and discomfort. They can also get infected.
Most cysts can be treated at home, providing they’re not infected. An infected cyst will be red and tender and it may also weep pus with an odor. An uninfected sebaceous cyst may be fairly large, but it will not be red and it will not have pus discharge.
Small sebaceous cysts can be treated at home using the following steps:
Trim the area around the cyst with scissors or using clippers (though use extreme caution to avoid hitting the bump with the clipper head.) This will allow you to monitor the lesion and it will help to prevent infection. If you leave the surrounding fur in place, discharge will get caked in the fur and it will form a small matt. This will hold the bacteria against the skin and the lack of air flow also makes it a perfect environment for infection.
Next, dampen a wash cloth and wrap it around a microwaveable heat pack. Apply the hot, warm compress onto the cyst for a period of 20 minutes. This will soften the skin and it will bring the sebum to the surface.
Disinfect the cyst and the surrounding skin using Betadine. If you do not have betadine, use hydrogen peroxide. Allow the disinfectant to air dry. Also, disinfect a large-diameter sewing needle by soaking it in Betadine or hydrogen peroxide for 2 minutes.
While the needle is soaking, wash your hands with anti-bacterial soap for 2 full minutes.
Lance the cyst with the disinfected needle. Drain the sebum by placing a finger alongside the cyst and gently pushing against the side of the bump. Move your finger around the cyst and repeat this process from different angles. Continue until there is no more white discharge (once it’s fully drained, you’ll likely get a small amount of blood or clear discharge.)
Swab the area with Betadine or hydrogen peroxide and allow it to air dry. Apply a small dab of antibiotic ointment to promote healing.
Do not bandage the wound and do not apply antibiotic ointment after the first day. Also, avoid squeezing the cyst while attempting to drain it, as this will push the sebum deeper into the skin. It can also cause the pore or follicle to burst beneath the skin, resulting in an even larger lesion.
Twice per day, disinfect the lesion with a mix of 50% water and 50% hydrogen peroxide. Allow it to air dry. Continue this routine until it’s healed. Most small cysts will heal without incident, but it’s important to monitor for signs of infection like redness, pus, swelling and so forth.
If you observe signs of infection, it’s important to seek treatment from your veterinarian. Your pet will likely require oral antibiotics. An infected cyst can turn into an abscess — a pocket of infection under the skin. The larger the cyst, the more likely it is to become infected, so it’s important to leave the larger lesions to the professionals.
Notably, large cysts (bigger than a pencil eraser) will likely need to be treated by your veterinarian. The reason: once the pore or hair follicle is damaged, it will simply re-fill with sebum and the cyst will re-form. Therefore, your veterinarian will need to excise the damaged portion of skin. It’s a simple procedure that’s completed in a matter of approximately five minutes. It may be done under general or local anesthesia.
Hairless rats are extremely prone to sebaceous cysts. Read about hairless rat care for tips on limiting the chances that your hairless rattie will develop one of these lumps!