A yellowish or white bump (or lump) on the skin is what a sebaceous cyst looks like. Most often sebaceous cysts are harmless but if you see pus or any other fluids leaking from it, you must learn that there is an infection that needs to be treated. Sometimes, these cysts go away on their own and sometimes, they remain in their place for a long time. The white or yellowish filling inside the cyst is made of proteins and oils secreted by the skin. Sebaceous cysts can grow on any part of the body except the palms and soles of the feet. Some men may even see them on their scrotum in large numbers.
There are hundreds of different types of cysts that form on the skin and the most common ones are:
- Epidermoid cysts (epidermal inclusion cyst) – they grow from the skin (where there are no hair follicles)
- Pilar cysts – they grow from hair follicles
- Sebaceous cysts – grow from the sebaceous glands under the skin. (Refer to the image to see how sebaceous glands look like)
You can just pinch off a sebaceous cyst or puncture it so that the fluids, called sebum inside it goes away and the body heals off the cyst. However, when you should be concerned about sebaceous cysts is:
- When you see plenty of cysts growing on your body (can be in the same area or different parts)
- When the cysts are draining pus and other fluids that usually indicates an infection.
A little bit on sebaceous glands and what they do?
Sebaceous glands are located under the skin all over the body except under the skin of palms and sole of the feet. A large number of sebaceous glands are found in the ear canal, scrotum, back, chin and forehead. Sebaceous glands produce fluid called sebum that comprise of:
- Wax esters
- Free fatty acids
- Cholesterol esters
What is the purpose of sebaceous glands secreting the sebum?
- Sebum reduces water loss from the surface of the skin
- A part of your natural body smell is contributed by the fluids secreted by sebaceous glands
- Sebum protects the skin from bacterial and fungal infections
- The bacteria colonised by the sebum, Propionibacterium helps in regulating the immune system.
Are sebaceous cysts cancerous?
Most often sebaceous cysts are not cancerous. Here are few symptoms that sebaceous cysts are harbouring the growth of cancer cells and when you should see a dermatologist or a cosmetic surgeon:
- When the cyst is very large (5 cms or more in diameter)
- When it continues leaking pus and fluids that’s painful and inflamed.
- Frequent recurrence even after removal.
In such cases, your doctor may take a sample of the sebum and send it for biopsy to look for cancerous cells under a microscope.
What causes sebaceous cysts?
The fluids secreted in the sebaceous glands under the skin usually get out of the body through the opening duct on the surface of the skin. If, for some reason, the opening on the skin is damaged due to an injury or an acne etc, the sebum from the gland tries to get out and forms a lump on the skin.
Diagnosing sebaceous cysts
You should see a good doctor if the cysts recur even after clearing them out. If your doctor sees that there is an infection, you may be put on antibiotics. If they keep recurring, a biopsy may be performed to look for cancer.
An ultrasound test may be required to determine the constituents of the cyst. A CT scan may also be required when your doctor thinks that you may need a surgery to clear out the cysts.
Treatment of sebaceous cysts
A small cyst occurring once in a while that goes away on its own is nothing to worry about. However, recurring and cysts in large numbers must be treated. Steroids may be injected for small cysts that are inflamed. Cysts may be drained off the fluids and in case of larger cysts, the total cyst needs to be removed under local anaesthesia. It is important to look for an experienced doctor to treat your skin problem because, when removing the cyst, no part of it can be left behind to prevent recurrence. If any part of the cyst is left inside the body, the cyst is sure to resurge.
Following methods may be used by our cosmetic surgeon or dermatologist to treat sebaceous cysts:
- Laser-aided excision – a neat and non-infecting way to puncture out the cysts
- Removing the cyst with an incision (depending on the size, the incision may be small or large)
- Punch excision – a small margin of skin around the cyst is removed using a scalpel.
If the cysts are infected, you will be put under antibiotics for a few days.