Pilonidal sinus - Features & risk factors
Pilonidal pits along the natal cleft
Most researchers believe that the primary event is an infection within a hair follicle and sebaceous gland unit (pimple, zit), leading to formation of a cavity beneath the skin with small openings (pits) in the skin, along the natal cleft.
As a secondary event, loose hairs or ingrowing hairs invade these pockets though the openings in the skin. As a secondary event, loose hairs or ingrowing hairs invade these pockets though the openings in the skin.
Pilonidal disease was first described and named in the 19th century. The word pilonidal comes from Latin for "a nest of hairs", meaning, containing an accumulation of hairs.
This is an acquired disease (not present at birth), which occurs usually in the cleft between the buttocks (sacrococcygeal area, natal cleft, tailbone area). It can seldom occur in the navel (umbilicus) and rarely, in other locations.
Development of a pilonidal unit:
1.Normal pilosebaceous unit. 2. infected unit (folliculitis). 3. pit and subcutaneous cavity formation
Pilonidal abscess
Pilonidal disease is prevalent in youngsters aging 15-25 years, but can occur at a younger or older age. Males are affected about 4 times more than females and are also more prone to recurrence after treatment. Local pain, discomfort while sitting, bloody or smelly discharge from the skin openings and a local swelling, are all possible signs of the disease and may go on for years with temporary ups and downs.
Occasionally, an abscess forms following acute infection, causing local swelling with intense tenderness and pain and requiring urgent surgical drainage (lancing).
Risk factors for pilonidal disease formation:
1. Inflammation of the sebaceous secretory glands in the skin leads to the formation of subcutaneous pockets with openings in the natal cleft. In the second stage, hairs penetrate through the openings, into the subcutaneous pockets. This type of inflammation is common during adolescence and in young people. It may be related to hormonal changes during this period.
2. A number of genetic-hereditary changes are known today that are characterized, among others, by obstructive and inflammatory disorders in the skin sebaceous glands. Those suffering from these genetic traits have an increased incidence of skin infections in the back, groin and armpit folds. They also have severe acne and pilonidal disorders. This inherited predisposition probably explains why some sufferers of pilonidal disease have close family members with a similar phenomenon.
3. Overweight: Obese may have a deep, humid, less ventilated natal cleft, creating an ideal environment for bacterial proliferation and causing skin maceration and infection.
4. Smoking increases the propensity for skin infections (perhaps by compromising the immune mechanism against skin infections).
5. Prolonged local injury: During World War II, pilonidal disease was nicknamed "Jeep riders disease" and was attributed to the damage caused by prolonged jerky rides in jeeps. In a study examining youngsters during military service, pilonidal disease was found to be more common in those engaging in driving professions.
6. Inadequate personal hygiene may contribute to pilonidal formation.
7. Tight clothes may promote local infection by pushing the buttocks toward one another and preventing ventilation of the cleft.
8. A history of previous surgery or treatment for pilonidal sinus carries an average risk of recurrence of around 20% or higher.
9. Hairiness, particularly dark/black, may contribute to pilonidal formation.
10. A combination of the factors above and mutual influence among them.
