A pilonidal cyst is an abnormal pocket-like structure in the skin. The cyst may resemble a large pimple located on the tailbone just above the cleft of the buttocks. Pilonidal cysts are typically filled with hair and skin debris and can develop into a painful abscess if they become infected.
Definition & Facts
Herbert Mayo was the first to describe this particular type of cyst in 1833. The cysts were given the name pilonidal by R.M. Hodge in 1880. The name is derived from the Latin words for hair and nest. Men are much more likely to develop pilonidal cysts than women. The condition is also more common among Caucasians than other groups.
In most cases, pilonidal cysts develop during the teen and young adult years. It is rare for someone to develop this type of cyst after age 40. Individuals, such as truck drivers, who sit for prolonged periods are also more likely to develop pilonidal cysts.
Symptoms & Complaints
- Redness and swelling at the bottom of the spine.
- Warmth at the site of the abscess.
- Pain along the tailbone.
- Pus or blood draining from an opening in the skin.
- Pus that is foul-smelling.
In addition to age and gender, risk factors for pilonidal cysts include obesity and having excess, coarse, or stiff body hair. Potential complications of the cysts include the possibility of recurrence, systemic infection, and a slightly increased risk of squamous-cell carcinoma at the site of the cyst.
Most pilonidal cysts occur when loose hairs become embedded in subcutaneous tissue through dilated hair follicles. The ingrown hair triggers an inflammatory response at the site, which causes the cystic structure to develop around the hair and skin debris. Friction, pressure, or other repeated trauma to the tailbone can force the hair into the skin. Tight clothing, bicycling, and skin rubbing against skin can all cause ingrown hairs that can lead to a pilonidal cyst.
During World War II, it was common for soldiers to develop cysts due to riding in bumpy Jeeps. The condition was actually called “Jeep disease” for a short time. It was during this period that many of the techniques for treating and managing the disease were first developed.
It is possible to develop pilonidal cysts in locations other than the tailbone. For example, dog groomers, barbers, and sheep shearers are prone to developing the cysts between their fingers due to the constant irritation from their scissors.
Diagnosis & Tests
To diagnose a pilonidal cyst, the doctor will start with a thorough patient history and physical examination. The history will attempt to uncover the patient’s specific risk factors for cysts. During the physical exam, the doctor will check for fever, inflammation of the skin surrounding the tailbone, and evidence of redness, tenderness, or swelling between the buttocks just above the anus.
In most cases, imaging studies and blood tests are not necessary for a diagnosis; however, the doctor may request a complete blood count to look for elevated white blood cells if a systemic infection is suspected. Most individuals first look to their primary care doctor for a diagnosis; however, they may require a referral to a dermatologist or surgeon depending on the severity of the cyst or abscess.
Treatment & Therapy
Initially, pilonidal cysts may only cause minimal pain, swelling, and redness. Sitting in a tub filled with warm water may ease the discomfort and reduce the chance that the cyst will become infected to the point of requiring draining. Antibiotics are typically only prescribed when there are signs that the skin infection is spreading. If the cyst is particularly painful, the doctor may prescribe medication to ease the pain.
The preferred method for treating a pilonidal cyst is incision and drainage during which the doctor removes the hair follicles and packs the resulting cavity with gauze. This is a simple procedure done under a local anesthetic. Since the area is left open until the cyst heals, the patient will have to keep the area clean by removing and repacking the wound with fresh gauze. The healing process can take as long as three weeks.
A procedure called marsupialization involves incision and drainage to remove pus and debris. The edges of the fibrous tract are then sewn to the edges of the wound to create a pouch. The wound is much smaller and shallower, so it does not need to be packed with gauze. Complete healing may take up to six weeks, and not all doctors are trained in this procedure.
A third option is incision and drainage followed by a complete closure of the wound. This eliminates the need for packing, but there is a higher rate of recurrence since is can be difficult to remove the entire cyst. This procedure is typically performed in an operating room by a surgeon specifically trained in the technique.
Prevention & Prophylaxis
Individuals can reduce the risk of ingrown hairs by shaving the area, using a depilatory cream, or getting electrolysis. Obese individuals can reduce their risk of developing cysts by losing excess weight. It is also helpful to avoid sitting for prolonged periods or activities that place repetitive pressure on the tailbone.