What Is a Pilonidal Cyst?

Medically Reviewed by Stephanie S. Gardner, MD on September 18, 2023
4 min read

There’s a type of cyst you can get at the bottom of your tailbone, or coccyx. It’s called a pilonidal cyst, and it can become infected and filled with pus. Once infected, the technical term is “pilonidal abscess,” and it can be painful.

It looks like a large pimple at the bottom of your tailbone. It is more common in men than in women. It usually happens more often in younger people.

People who sit a lot, such as truck drivers, have a higher chance of getting one.

They can be treated. If your cyst becomes a problem, your doctor can drain it or take it out through surgery.

Most doctors think that ingrown hairs are the reason for many of them. Pilonidal means "nest of hair," and doctors sometimes find hair follicles inside the cyst.

Another theory is that pilonidal cysts appear after a trauma to that region of your body.

During World War II, more than 80,000 soldiers got pilonidal cysts that put them in the hospital. People thought they were because of irritation from riding in bumpy Jeeps. For a while, the condition was called "Jeep disease."

You might be more likely to get one if you were born with a small dimple in the skin between your buttocks. This dimple can tend to get infected, though doctors aren’t exactly sure why.

Other risk factors include obesity, large amounts of hair, not enough exercise, prolonged sitting, and excessive sweating.

The symptoms of a pilonidal cyst include:

  • Pain, redness, and swelling at the bottom of the spine
  • Pus or blood draining out of it
  • Bad smell from the pus
  • Tenderness to the touch
  • Fever

They can vary in size. Yours may be a small dimple or cover a large, painful area.

A pilonidal cyst is an abscess or boil. Treatment may include antibiotics, hot compresses and topical treatment with depilatory creams. In more severe cases it needs to be drained, or lanced, to heal. Like other boils, it does not get better with antibiotics.

If you have any of the symptoms, call your doctor.

Your doctor can diagnose a pilonidal cyst with a physical exam and by asking you questions about it. Among the things they may ask you:

  • When did you first feel symptoms?
  • Have you had this problem before?
  • Have you had a fever?
  • What medications or supplements do you take?

Early in the infection of a pilonidal cyst, the redness, swelling, and pain may not be too bad. Some things you might want to try:

  • To ease any pain, soak in a tub of warm water. Sometimes, your cyst may open and drain on its own this way.
  • Take nonprescription pain medicine, but follow the dosing instructions.
  • Keep the cyst and area around it clean and dry.

Antibiotics do not heal a pilonidal cyst. But doctors have any number of procedures they can try. Here are some options:

Incision and drainage: This is the preferred method for a first pilonidal cyst. Your doctor makes a cut into the cyst and drains it. They remove any hair follicles and leaves the wound open, packing the space with gauze.

Advantage -- It’s a simple procedure done under local anesthesia, meaning just the area around the cyst is numbed.

Disadvantage -- You have to change the gauze often until the cyst heals, which sometimes takes up to 3 weeks.

Marsupialization: In this procedure, your doctor makes a cut and drains the cyst, removing pus and any hair that are inside. They’ll sew the edges of the cut to the wound edges to make a pouch.

Advantages -- This is outpatient surgery under local anesthesia. It also lets the doctor make a smaller, shallower cut so that you don’t need to take out and repack gauze daily.

Disadvantages -- It takes about 6 weeks to heal, and you need a doctor specially trained in the technique.

Incision, drainage, closing of wound: In this technique, the cyst is drained, but it’s not left open.

Advantage -- You don’t need to pack gauze because your doctor fully closes the wound right after surgery.

Disadvantages -- You’re more likely to have more problems with the cyst down the road. It’s harder to remove the entire cyst with this method. It’s usually done in an operating room with a specially trained surgeon.'

Other surgical procedures include complete cyst and cyst wall excision along with the pilonidal sinus tracts, the use of fibrin glue, and taking (core out) only diseased tissue and the cyst out with punch biopsies.

Follow all of your doctor’s instructions about at-home care, especially if you need to remove and pack gauze. Other tips:

  • Try to keep the area clean.
  • Check for any signs of a new infection, such as redness, pus, or pain.
  • Keep your follow-up appointments with your doctor so they can see how your cyst is healing.

A complete cure is possible, but remember that a pilonidal cyst may recur even if you had one surgically removed.