What Causes Pilonidal Disease to Develop?

What Causes Pilonidal Disease to Develop

Well, we do know that pilonidal disease typically develops in people with deep natal clefts (the valley between one’s buttock cheeks). This has been shown in studies.  So, it’s felt that a deep cleft is a necessary factor.  While pilonidal disease can develop in people with more shallow clefts, that’s not as common.  

Deep clefts that are “tight” often stay moist and don’t permit air to reach the skin in the middle of the cleft.  How wounds in clefts and pilonidal disease develops is still a bit controversial.  Several theories exist and all the factors they describe may contribute.

In the follicular occlusion theory, hair follicles in the cleft midline skin become occluded with a protein called keratin.  A small abscess (infection such as in acne) develops and ruptures into the fat-filled area under the skin and a larger abscess develops.  The keratin plug falls out and now the former hair follicle is a hole connected to the underlying abscess.  Hair can now insert into the abscess.  Barbs on hair make it insert from its root end and prevent it from falling out.  The hair that accumulates is shed hair, not ingrown hair.  That’s why local hair removal is not helpful.  Often the infection borrows its way up to the top of the cleft where it can break through the skin and form a sinus.  The accumulation of hair in pilonidal disease is felt to be propelled by the natal cleft vacuum that occurs with sitting and standing.  The hairs in a pilonidal abscess line up in parallel and resemble a nest which is what pilonidal means, nest of hair.  This theory explains why pilonidal disease strikes after puberty in the acne years, acne also being a follicular occlusive disease of hair follicles, oil glands, and sebaceous glands.

A competing theory is the direct hair insertion theory.  In this theory, cut hair from the back of the head after a haircut drops down into the cleft and directly inserts through the midline skin of the cleft.  This theory has been proven to be operative in at least some cases of pilonidal disease.

Then there are cases that don’t seem to be explained by either theory.  Some people develop primary wounds in the natal cleft midline.  This may be due to trauma to the natal cleft skin midline.  When wounds develop in the natal cleft midline, they struggle to heal due to the moist airless environment.

Regardless of the cause of pilonidal disease, a proper surgical procedure such as the Cleft Lift Procedure cures and prevents recurrence in most instances.

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After many years performing major abdominal operations including open and laparoscopic resections for colon cancer, rectal cancer, Crohn’s disease, and Ulcerative colitis, I have chosen to concentrate my efforts in a few highly specialized areas of surgery where I feel I can make the greatest positive impact on patients.

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