Difference between pilonidal cyst, abscess and sinus

The term pilonidal disease refers to the formation of cysts, abscesses and boils formed in the natal cleft region of the buttocks. These eruptions within the skin are caused beneath the tailbone and can originate from a number of sources and be due to a number of reasons.

These infections can occur in a variety of forms, including inflamed red skin, sore spots and pus filled boils. Some of the most common terms associated with pilonidal disease are Pilonidal Cyst, Pilonidal Sinus and Pilonidal Abscess.

In common parlance these terms are often used interchangeably since they refer to a similar kind of infection. It has become so common that in general reference these three terms imply the same condition and act as synonyms for one another.

However, if one is to trace the technical medical roots and study each of these individually, it becomes apparent that they are entirely different conditions.

Pilonidal Cyst

The pilonidal cyst is a cyst or a boil that is formed from within the skin. It begins as an infection from underneath the skin and begins to get aggravated and worsens as more and more debris collects in the skin and blocks the pores. As the cyst forms underneath the skin it also starts to push outward.

With the increase in infection it then erupts outward in the form of pus filled boil, which is then known as an abscess. The abscess can be surrounded by red patches and sore, inflamed skin.

Pilonidal Abscess

A pilonidal abscess is an outward formation that generally grows towards the left-hand side of the natal cleft of the buttocks. Depending on the severity of the infection and the individual details of the case there can be more than one pilonidal abscess formed in the region.

Pilonidal Sinus

On the other hand a pilonidal sinus refers to a cavity in the region that leads from the cyst and the abscess to external layers of the skin. The pilonidal sinus acts as a link between the cyst and other regions of the body. It is formed as a hollow “tunnel” below the pilonidal abscess.

There can be a number of pilonidal sinuses running from one abscess to another and these act as a gateway for the infection to travel further. The pilonidal sinus generally forms at the center of the natal cleft, at the very middle of the buttocks.


Michael Lynch is a former pilonidal cyst sufferer, freelance medical health researcher and writer. He devotes much of his free time helping other sufferers deal and cope with this terrible disease. Contact Michael

One Response to Difference between pilonidal cyst, abscess and sinus
  1. Charley
    March 3, 2012 | 7:50 PM

    Thanks for this. It really cleared things up for me.

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