How You Got It
There is a basic set of factors that underlie a person's susceptibility to the disease, this is certainly not an all-inclusive list, these are only KNOWN risk factors:
- Family history of Pilonidal Disease
- Fetal development problems (Spina Bifida Occulta)
- Shape, size and scaliness of the person's hair
- Amount of hair in the natal cleft & buttocks
- Size of the pores in the skin over the tailbone
- High degree of friction and pressure on the tailbone (such as sitting improperly)
- Traumatic injury to the tailbone (such as a fall)
- Participation in high tailbone-impact activities (such as horseback riding)
- Depth of the natal cleft (impacted by weight and genetics)
- Shape of the natal cleft (overhanging areas, dips)
- Tendency towards blocked hair follicles (acne, boils, sebaceous cysts)
- Tendency towards other skin problems (eczema, etc...)
This organization has chosen to follow the philosophies of Dr. John Bascom, who is largely considered the foremost expert in the world in the treatment of Pilonidal. Now retired, Dr. Bascom has done over 600 Pilonidal surgeries throughout his career.
Understanding Follicular Occlusion:
Follicular Occlusion is medical terminology for "blocked pores." Which is to say that pores in the midline of the natal cleft (more pretty language, this time meaning butt crack) becoming stretched and blocked with debris. On most other body parts this process results in a common pimple; the natal cleft, however, is a special place where lack of oxygen allows anaerobic bacteria to frolic and thrive. But we will come back to bacteria in a moment.
How the pores got stretched and infected - when the body rises from a sitting position, gravity naturally exerts force pulling the tissues in the midline down at the same time as the body is being propelled upward. The pull of gravity stretches the pores in the midline and so does another culprit - slouch sitting. Mother nature endowed us with "sit bones" at the junction of our legs and buttocks, but many of us are a little lazy when we sit and we slouch forward in our chairs (raise your hand if you are doing this RIGHT NOW!) So, there you are with some pores in your midline that have become stretched out wider than they should be. They might look like this:
Once the follicles have been stretched out, they provide a very convenient place for stuff to collect: dead skin cells, sweat, clothing lint and hair. As the crud fills in the stretched pores, they become blocked and the oils (sebum) that are naturally secreted can no longer flow and they back up inside the follicle. As the crud builds up, the follicle becomes inflamed and eventually ruptures. Once the follicle has ruptured, it now provides a handy opening for the anaerobic bacteria (we told you we would meet Mr. Bacteria again) to enter the fatty tissues below the skin. Here in Pilonidal world, we now call this a pit.
The pit is the start of a Pilonidal abscess. With the natural barrier of skin breached, the anaerobic bacteria that normally live in the body locations where there is no oxygen, can go off exploring in the fatty tissues of your behind. Infections caused by anaerobic bacteria are characterized by abscess formation, foul-smelling pus, and tissue destruction. For those of you reading this right now with an ache at the top of your natal cleft, this should be starting to sound very familiar....
One thing that continues to raise questions are those people who develop a Pilonidal after a traumatic tailbone injury. The speculation from our team of Medical Advisors is that at the time of the injury there may have been a common pimple or even a pit already formed in the midline of person experiencing trauma to the tailbone area. The trama disrupts the normal defenses in tissue, leaves the area swollen and breakes the tissue walls that normally isolate pimples/pits to prevent infection. With the defense system down, bacteria moves in and an abscess results.
(My personal experience as a person prone to Pilonidals is that this process of follicle stretching & blocking is constant in the midline and can be stopped at the early stages if you know what to look for. I've had easily 8 instances since my surgery in 2000 where a pimple formed in the midline and I was able to treat it with No Bump to keep it from turning into a new abscess.)
Hair - even though Pilonidal technically means Nest of Hair, only 50% of abscesses have hair in them. It has been noted that because of the scales on a hair shaft, hair does travel into a pit or sinus when the base of the hair is pressed into the opening - as through normal friction of the buttocks. Surgeons looking at removed Pilonidals have found hairs from the heads of patients and hairs from patient's bedmates snuggled into the Pilonidal abscess.
It's a family affair - it is common for Pilonidal Disease to run in families and it has been suggested in medical literature that this is due to an inherited shape/depth of the natal cleft and inherited skin risk factors. Just one more genetic gift from Mom and Dad!
Friends & neighbors - Pilonidal is linked with 3 other conditions in what is known as the Follicular Occlusion Tetrad (Acne Conglobata, Dissecting Cellulitis, Hidradenitis Supperativa, Pilonidal.) All 4 diseases share common cytokeratin expression that is unique to the group. We regularly find people who are actually suffering from Hidradenitis Supperativa that have been diagnosed with Pilonidal.
Congenital Pilonidal - it is not at all uncommon for babies to be born with a Sacral Dimple and it is important to note that this is not the same as a Pilonidal abscess as it is discussed on this site even though your pediatrician might refer to it (wrongly) as a Pilonidal Dimple. A condition known as Spina Bifida Occulta (spine failing to close fully during gestation) can leave a hole over the tailbone that resembles a Pilonidal sinus opening and there is often hair at the site of the defect, this occasionally develops into Pilonidal Disease later in life. Other problems during fetal development can leave a "hollow" area at the base of the spine, which can lead to Pilonidal Disease later in life. Many years ago it was believed that all Pilonidal Cysts were congenital - the majority of surgeons now believe that most cases are acquired. If you are seeing a doctor who is telling you that all Pilonidals are congenital, then it is highly recommended that you find another doctor. It was common theory 20 years ago that Pilonidal was congenital but nobody who's up on current treatment or theory still believes that.
This page last updated: 09/16/2010