(Pilonidal Sinus; Pilonidal Abscess)
is a fluid-filled developmental defect at the base of the spine.
refer to different stages of the disease process.
- Cyst—not infected
- Abscess—pocket of pus
- Sinus—opening between a cyst or other internal structure and the outside
While the cyst is not serious, it can become infected and may need to be treated if problems develop. When a pilonidal cyst gets infected, it forms an abscess, eventually draining pus through a sinus.
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A pilonidal cyst may be congenital or acquired. If congenital, it probably began as a defect that existed when you were born. Sometime later, the defect allowed an infection to develop. If acquired, it may be the enlargement of a simple hair follicle infection or the result of a hair penetrating the skin and causing an infection.
The following factors increase your chance of developing a pilonidal cyst:
Personal or family history of similar problems such as
boils, carbuncles, folliculitis,
- Large amounts of hair in the region
- Tailbone injury
- Horseback riding, cycling
- Prolonged sitting
A pilonidal cyst may cause:
- Painful swelling over your sacrum, which is the area just above your tailbone
- A foul smell or pus draining from that area
You will be asked about your symptoms and medical history. A physical exam will be done. You may be referred to a surgeon for treatment. There are no diagnostic tests required.
Talk with your doctor about the best treatment plan for you. The choice of treatment will depend on the extent of the condition and your general overall health. Treatment options include:
As with all localized infections under the skin, warm water soaks will draw out the infection. This will not completely cure the condition, but it will help.
Incision and Drainage
The abscess is lanced, the pus drained, and the wound is packed with sterile gauze. This helps it heal from the inside out. But, this usually does not cure the problem because abnormal tissue remains.
To completely cure the condition, all affected tissue needs to be removed. It may be considered if you have repeated infections. This is a more extensive surgical procedure than simple incision and drainage. The surgical wound may be closed with sutures or left open to heal from the inside.
Laser Hair Removal
There are recent reports that laser hair removal in the area may be an effective treatment for pilonidal cysts.
To help reduce your chance of a pilonidal abscess:
- Keep the area clean and dry
- Avoid sitting for a long time on hard surfaces
- Remove hair from the area
American Society of Colon and Rectal Surgeons
Family Doctor—American Academy of Family Physicians
The College of Family Physicians of Canada
Pilonidal cyst. American Academy of Family Physicians website. Available at:
http://familydoctor.org/familydoctor/en/diseases-conditions/pilonidal-cyst.html. Updated April 2014. Accessed August 6, 2015.
Pilonidal cyst. Swedish Medical Center Seattle website. Available at:
http://www.swedish.org/services/colon-and-rectal-clinic/services/pilonidal-cyst#axzz2d6pXFkit. Accessed August 6, 2015.
Pilonidal disease. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T114205/Pilonidal-disease. Updated March 9, 2016. Accessed September 26, 2016.
Pilonidal sinus and cysts. The Children's Hospital of Philadelphia website. Available at:
http://www.chop.edu/service/surgery-general-thoracic-and-fetal/conditions-we-treat/pediatric-surgery-pilonidal-sinus-and-cysts.html. Updated January 1, 2011. Accessed September 17, 2015.
Sadick NS, Yee-Levin J. Laser and light treatments for pilonidal cysts.