Coccyx fistula

and Martina Feichter, medical editor and biologist

Sabine Schrör is a freelance writer for the medical team. She studied business administration and public relations in Cologne. As a freelance editor, she has been at home in a wide variety of industries for more than 15 years. Health is one of her favorite subjects.

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Martina Feichter studied biology with an elective subject pharmacy in Innsbruck and also immersed herself in the world of medicinal plants. From there it was not far to other medical topics that still captivate her to this day. She trained as a journalist at the Axel Springer Academy in Hamburg and has been working for since 2007 - first as an editor and since 2012 as a freelance writer.

More about the experts All content is checked by medical journalists.

A pilonidal sinus (pilonidal sinus or pilonidal sinus) consists of small ducts and cavities under the skin in the area of the gluteal folds. It is based on inflammation in the subcutaneous fatty tissue. In addition to asymptomatic coccyx fistulas, there are also those that form accumulations of pus (abscesses) or that are chronic. Read more about the causes, symptoms, diagnosis, treatment and prognosis of a coccyx here!

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work. L05

Brief overview

What is a coccyx fistula? An acute or chronic inflammation in the subcutaneous fatty tissue in the area of the coccyx; Medical term: pilonidal sinus (pilonidal sinus)
Causes: Rarely congenital, mostly acquired - by drilling short hairs into the skin as a result of friction; In the subcutaneous fatty tissue, the tissue around the foreign body becomes inflamed and changes
Symptoms: asymptomatic coccyx fistula: punctiform skin indentation on the coccyx; Abscessing coccyx fistula: painful, reddened swelling, possible discharge of pus or fever; chronic coccyx fistula: constant or intermittent leakage of clear or bloody fluid
Diagnosis: On the basis of the characteristic skin changes and - in the case of chronic coccyx fistulas - the secretion of fluid during palpation.
Treatment: operation for acute (abscess) and chronic fistula on the buttocks; an asymptomatic coccyx fistula does not require therapy
Prognosis: no spontaneous healing; Relapses (recurrences) possible after successful treatment; Skin cancer as a very rare long-term consequence of long-term chronic coccyx fistula

Coccyx fistula: description

"Tailbone fistula" (also "tailbone cyst") is the unclean name for a pilonidal sinus (sinus pilonidalis) occurring in the coccyx region. This is an acute or chronic inflammation in the subcutaneous fatty tissue. It usually develops in the coccyx region (more precisely: in the vascular fold there), hence the name coccyx fistula. A pilonidal sinus can also form on other parts of the body, for example in the area of the nipple, navel, female pubic region, penis, nose, between the fingers or behind the ears.

Ingrown hair

The Latin technical term Sinus pilonidalis indicates the appearance and development of the skin changes: "Sinus" means cavity, "nidus" stands for nest and "pilus" for hair.Those affected have a small cavity, often with a broken, ingrown hair or a ball of hair under the skin (hence the term "hair fistula" or "hair nest dimple"). More or less branched, small passages lead from the cavity, which can lead to the surface of the skin through a small opening (porus, plural: pori).

What is a fistula? The term generally denotes non-natural, tubular connections between cavities in the body or a cavity and the body surface.

Forms of a coccyx fistula

There are three different manifestations of coccyx fistulas:

Asymptomatic coccyx fistula: This fistula on the buttocks does not cause any discomfort. It is therefore usually only discovered by chance on the basis of the mostly punctiform skin depressions - the pori - in or near the gluteal folds. Sometimes it changes into the acute abscess or the chronic form.
Acutely abscessed coccyx fistula ("coccyx abscess"): This is a coccyx fistula with an accumulation of pus (abscess), recognizable by a painful swelling, usually in or next to the gluteal fold. Pus may emerge from the openings in the fistula.
chronic coccyx fistula: This is the most common form of coccyx fistula. A clear to bloody purulent fluid escapes from the skin opening continuously or intermittently.

Incidence of coccyx fistulas

The frequency of the pilonidal sinus has been increasing in Europe and North America for some years for unknown reasons. For example, in 1995 about 26 out of 100,000 people in Germany developed a fistula on the tailbone. In 2012 there were already 48 out of 100,000 people. Men in the 2nd and 3rd decades of life are most frequently affected.

Coccyx fistula: diagnosis

A physical examination is usually sufficient to diagnose a coccyx fistula. The doctor often recognizes the fistula based on the characteristic skin changes: punctiform depressions in the skin in or next to the anal fold. Chronic coccyx fistulas release a clear or bloody, now and then purulent fluid through an opening in the skin when pressure is applied.

Further examinations such as imaging procedures (e.g. ultrasound, computed tomography) are not necessary in the vast majority of cases.

Coccyx fistula - which doctor is responsible? Most often, proctologists - specialists in diseases of the rectum - and dermatologists (dermatologists) take care of a pilonidal sinus on the tailbone.

Exclusion of other causes

The symptoms associated with a coccyx fistula can also occur with other diseases. The doctor must therefore rule out the following clinical pictures, for example, when making a diagnosis:

Anal fistulas: These are ducts and cavities under the skin in the area of the sphincter muscle or rectum. Like coccyx fistulas, they can become inflamed and form an abscess on the buttocks. The symptoms then resemble those of an abscessing coccyx fistula.
Fistulas in Crohn's disease: Even in chronic inflammatory bowel disease, fistulas can form in the anal area.
Acne inversa: In this skin disease, inflamed sebum glands, hair roots and sweat glands appear, mostly in the genital area or under the armpits. This can lead to purulent abscesses and fistulas.

Coccyx fistula: formation and causes

A coccyx is rarely congenital. It then often occurs in connection with childhood malformations of the spinal cord and spinal canal, for example spina bifida ("open back"). In addition, high levels of phenytoin (an anti-epileptic agent) in the blood of a pregnant woman can cause a pilonidal sinus in the unborn child.

In most cases, however, a coccyx fistula is acquired. It often forms during puberty - possibly in connection with a genetic predisposition (the pilonidal sinus occurs more frequently in some families). Overall, the fistula on the buttocks arise from several factors.

Short and sharp-edged hairs falling from the head or broken hair can dig into the skin through rubbing movements - particularly easily in the buttocks crease through the movement between the buttocks. Such hair can penetrate into the subcutaneous fatty tissue. The fine horn scales of the hair act as a kind of barbs and prevent the way back. As the hair penetrates further and further into the skin, the typical depressions (pori) are created.

In the deep fat tissue, the hair is a foreign body. Chronic inflammatory processes develop around the foreign body and new tissue is formed in the form of nodules - a foreign body granuloma. This does not heal spontaneously (asymptomatic coccyx fistula), but can become infected and cause symptoms as a result (as abscessing or chronic coccyx fistula).

Risk factors for discomfort

The following factors can favor the transition from an asymptomatic coccyx fistula to an abscessing or chronic fistula on the buttocks:

thick hair
Obesity (obesity)
Military service, frequent short haircuts

Some studies also suggest that increased adipose tissue and the depth of the anal folds can promote the development of a coccyx fistula. According to the current state of knowledge and contrary to previous assumptions, however, it has not been proven that poor hygiene promotes coccyx fistulas. However, showering or bathing regularly will help remove any hair residue.

Coccyx fistula: symptoms

The symptoms a coccyx fistula triggers depends on the respective shape. The following symptoms occur with coccyx fistulas:

Asymptomatic coccyx fistula

If the coccyx fistula is in the initial stage, there are no symptoms. Such asymptomatic coccyx fistulas can only be recognized by their typical appearance: small, mostly punctiform skin depressions (pori or pits) in the area of the gluteal folds.

Abscessed coccyx fistula

This form of the coccygeal fistula manifests itself as very painful, lump-like swellings in or next to the gluteal fold. Due to the inflammation, the affected skin area is reddened and feels warm. If the pilonidal abscess bursts, purulent fluid usually escapes. You may have a fever.

Chronic coccyx fistula

Chronic coccyx fistulas can ooze or exude bloody, purulent fluid. Clear or bloody secretions can escape continuously or only temporarily through the skin openings (pori).

A chronic coccyx fistula can change into the acutely abscessing form at any time.

Tailbone pain has other causes

Acute coccyx fistula, in particular, can cause pain in the coccyx area. Apart from its position, the pilonidal sinus has nothing to do with the coccyx. Although the fistula occurs close to the tailbone, direct tailbone pain usually has other causes. For example, they can be due to a tailbone inflammation. A bruise sustained in a fall can also cause pain in the tailbone. These are particularly noticeable when sitting. It may also be that the pain in the tailbone extends into the intestines and occurs more intensely during bowel movements.

Coccyx fistula: treatment

Asymptomatic coccyx fistula does not heal on its own, but lasts for life. But it does not have to be treated. However, if it turns into an abscessing coccyx fistula - i.e. forms an abscess - doctors recommend a quick operation.

The doctor first opens the abscess so that the pus can drain away. As soon as the acute inflammatory reactions have subsided (after about 10 to 14 days), the actual coccyx fistula is operated on. The surgeon can choose from various procedures.

These can also be used in the treatment of chronic coccyx fistulas. The exact treatment is decided on a case-by-case basis. In the case of smaller abscesses, it can sometimes be sufficient to open them with a small incision (simple incision).

Coccyx Fistula: Surgical Procedure

Often, minimally invasive surgical procedures are used for abscessing or chronic coccyx fistula. In other cases, median excision procedures or plastic procedures are chosen.

The various surgical procedures differ in their advantages and disadvantages, for example with regard to the relapse rate and wound healing time. Ask your doctor for more detailed advice on this.

Minimally invasive procedures

Minimally invasive techniques for treating a pilonidal sinus can also be performed on an outpatient basis. Local anesthesia is usually sufficient for the procedure. Examples of such surgical procedures are:

"Pit picking": The disease-related skin openings (pits) including a few millimeters of the surrounding tissue are cut out (excision) under local anesthesia. This procedure is recommended for locally limited coccyx fistulas.
Sinusectomy: Here only individual fistula ducts are surgically removed. The patient receives a local anesthetic for this. The resulting wounds are then left open to heal and regularly rinsed out with tap water.

The minimally invasive therapy methods for coccyx fistulas also include laser-based techniques. They are quite popular among the population because they promise optimal healing results with comparatively minor surgery. However, the scientific data on this is still thin. Laser treatment for coccyx fistulas is therefore not yet recommended.

The same applies to endoscopic procedures. The doctor cuts out the skin openings in the middle line. He then supplies the coccyx fistulas in the subcutaneous fatty tissue - under view using an endoscope, i.e. a device with a light source and camera. The data from the first studies are promising, but the method is comparatively expensive.

The guideline experts do not (yet) recommend splitting the coccyx fistula (fistulotomy) using the lay-open method either, as the study data on this minimally invasive surgical method are insufficient. Here the surgeon opens the fistula duct up to the hair nest, but does not cut out the fistula system completely. The resulting open wound is usually smaller than with conventional procedures. However, depending on the study, there are sometimes considerable relapse rates, according to which up to over half of the patients developed a coccyx fistula again.

Median excision procedures

Median excision procedures are considered to be "traditional" or "classic" surgical methods. This is because they have been carried out using almost unchanged technology since at least the 1980s. In addition, they are still the most common methods of coccyx surgery worldwide today.

Specifically, with this therapy method, the pilonidal sinus is cut out in such a way that the resulting wound comes to lie in the midline (median line) - the previously deepest point of the anal fold. Larger interventions are usually carried out under general or "partial anesthesia" (regional anesthesia).

Of the various median excision procedures, the most common excision in Germany is performed with open wound treatment (inpatient or outpatient). The wound created by cutting out the fistula in the median line remains open and is rinsed out several times a day with clear tap water. Leaving it open and cleaning it every day causes scar tissue to form over time that does not contain hair roots or sebum glands. This lowers the risk of a new fistula.

Plastic procedures (off-midline procedures)

General anesthesia or "partial anesthesia" (regional anesthesia) is usually required for these types of coccyx surgery. The term "plastic" refers to the type of wound care: The wound that is created by cutting out the pilonidal sinus is covered with flaps made of skin and subcutaneous fatty tissue. So after the healing process, no “hollow” remains in the tissue. Because the cut is typically made to the right or left of the center line, these surgical procedures are also referred to as "asymmetrical" or "off-midline procedures".

Pilonidal sinus surgery: how long have you been sick?

Many patients ask themselves about the surgical treatment of the fistula on the buttocks: How long have I been sick, i.e. unable to work? The answer to this depends on the extent of the intervention. For example, patients are usually fit again after a few days after an outpatient pit picking treatment. In the case of larger interventions with open wound treatment, on the other hand, longer failures are to be expected.

Depending on the size of the wound, a recovery period of several weeks or even months can follow. It is best to ask your doctor. He can estimate the healing time in individual cases and issues the corresponding certificate of incapacity for work.

Treat coccyx fistula yourself?

Under no circumstances should you try to treat a coccyx fistula yourself! An abscessing pilonidal sinus, in particular, can worsen if, for example, one tries to express the abscess like a pus pimple. Leave the treatment to an experienced medical professional (proctologist or dermatologist).

Coccyx fistula: course and prognosis

A fistula does not heal on its own, nor does the coccyx fistula. Even the asymptomatic coccyx fistula does not go away spontaneously. However, it usually does not get worse, so preventive treatment is not necessary. On the other hand, abscessing and chronic coccyx fistulas are operated on - in the case of coccyx abscess, the operation is urgently necessary; in the case of chronic pilonidal sinus, the appointment of the operation can be arranged with the patient (elective operation).

Relapse rate

Coccyx fistulas can reappear even after successful treatment (medical: recur). The recurrence rate - i.e. the proportion of patients in whom the fistulas return after therapy - depends, among other things, on the treatment method. However, the currently available information on this is only valid to a limited extent because it is based on studies in which a relapse (relapse) is defined differently or not at all.

In this respect, no generally valid, reliable information can currently be given on the recurrence rate of coccyx fistulas. It is best to ask your treating doctor how high he assesses the risk of relapse in your case.

Rare sequelae: cancer

The chronic pilonidal sinus on the tailbone very rarely results in squamous cell carcinoma - a form of skin cancer - as a long-term consequence. It usually affects patients who have had coccyx fistula for more than 15 years.

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