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Pilonidal Sinus: What Is It, Causes, and Treatment Options?

Pilonidal sinus is a condition characterized by the accumulation of hair beneath the skin in the coccyx region. It can rarely occur in the navel and between the fingers (common among hairstylists). In Latin, it is referred to as pilonidal sinus, where “pilos” means hair, and “sinus” means sac. In this context, the Turkish term does not accurately describe the condition. In reality, there is no “ingrown hair”; instead, it involves hair or other substances piercing the skin and entering the subcutaneous layer.

Different schools of thought also use terms like dermoid cyst sacral, sacral cyst, or pilonidal cyst.

In essence, the description of “ingrown hair” corresponds to the growth of ingrown hairs beneath the skin. The condition observed in the coccyx area is not caused by the curling of local hairs but occurs when hairs, feathers, clothing dust, and similar particles from above pierce the skin and enter the subcutaneous layer. It is not the result of the hairs in the area curling.

Why Does Pilonidal Sinus Occur, and What Are the Causes?

The formation of pilonidal sinus, which constitutes 99% of cases in the coccyx region, is explained as follows: Hairs falling from the nape of the neck and feathers shedding from the back and shoulders fall downward, getting trapped between the buttocks.

The hair caught between the buttocks, during the frictional movement of the buttocks while walking, rotates like a drill bit, piercing the skin and forming a knot beneath the skin. The time it takes for the hair to fall and pierce the skin is approximately 8-10 hours. If the shed hairs in the region are removed more frequently, the occurrence of pilonidal sinus can be prevented. The cause of the condition is not the hairs in the coccyx region but the hairs falling from above.

The cause of ingrown hairs in the navel is similar. It occurs as the hairs around the abdomen shed and accumulate in the navel pit, gradually increasing in quantity.

The occurrence of ingrown hairs between the fingers, a rare condition, is associated with hairstylists. During the rapid scissor movements while cutting hair, the client’s hairs can pierce the skin, entering beneath it.

In the legs, groin, and the lower parts of the beard that men shave daily, ingrown hairs are considered separately as a different issue.

What Are the Symptoms of Ingrown Hair?

In most patients, ingrown hair is incidentally detected because, under normal circumstances, it does not present significant symptoms. In routine examinations of a military barracks, it has been observed that up to 70% of patients with ingrown hair are not even aware of their condition. The following symptoms are found in patients who do exhibit signs:

Opening at the Coccyx: There is a hole at the coccyx, and there can be one or multiple openings in the region. These openings can be as small as a pinhole or as wide as to allow the insertion of a pencil. Every patient has them.

Discharge: Discharge is a secretion produced by the body to dissolve the hairs beneath the skin. It is not a microbial infection.

Swelling beneath the Skin: Swelling can take the form of a pea, almond, or walnut. It is the accumulation of hairs forming a knot, a structure known as a sinus.

Pain: If there is inflammation, pain may be caused by the infection. If there is no inflammation, pain can result from the compression of the sinus.

Diaper Rash in the Buttocks: The discharge irritates the skin, leading to the formation of diaper rash.

Unpleasant Odor between the Buttocks: Discharge can cause an unpleasant odor.

Itching between the Buttocks: Irritation and diaper rash on the skin can cause itching.

Burning Sensation at the Coccyx: Again, this occurs due to irritation and is infrequently observed.

How and Where Does Ingrown Hair Occur?

The formation of ingrown hair varies depending on where it occurs.

Between Fingers and Toes: Almost all cases in the hands, such as between fingers or next to nails, are observed in female hairdressers. The parts of the fingers dealing constantly with hair during cutting cause the hairs between the nail parts and between the fingers to penetrate under the skin. Once a hair enters, a hole is formed, allowing other hairs to easily enter.

Around the Navel: Ingrown hairs around the navel are more common in overweight individuals with a deep navel. They are more frequently encountered in men with hair around the navel. Hairs falling from the chest or abdominal area accumulate in the navel, leading to discharge over time.

Coccyx Region: Those occurring in the coccyx region constitute approximately 99% of all cases, making it the most common area. Hairs falling from the back of the head, the back of the neck, the back, and the shoulders get trapped between the buttocks.

The hair trapped between the buttocks rotates around its own axis, creating a drilling motion like a drill bit as the buttocks move. With this motion, it pierces the skin and enters beneath it.

A second, but less widely accepted view, is as follows: When rising from a seated position, negative pressure is created between the buttocks. This negative pressure, according to this perspective, pulls the hair beneath the skin due to a vacuum effect. However, this view has fewer proponents.

The previously believed notion of hairs in the region growing beneath the skin has been completely abandoned because microscopic examinations have shown that the emerging hairs are not from the region.

How to Recognize the Onset of Ingrown Hair?

When the area between the buttocks is examined closely under bright light, one or multiple entry holes can be observed either in the midline or very close to the midline. These holes are as wide as only a sewing needle can enter.

A small swelling under the skin may be noticed, but even if there is no swelling, the diagnosis of ingrown hair is confirmed if there are entry holes. In other words, unless there is a hole, the diagnosis is doubtful, and the presence of a hole is the indispensable sign of the disease and the initial symptom at the onset of the condition.

If in doubt, a visit to a specialist doctor is necessary to confirm the diagnosis. The presence of discharge indicates that the initial stage has already passed.

Sometimes, a definitive diagnosis cannot be made through examination alone, and in such cases, superficial ultrasound can be a guiding tool. However, this is a rarely needed practice for an experienced surgeon (1).

How Is Ingrown Hair Surgery Performed?

There are more than 30 surgical methods developed up to the present day, and a significant portion of these has been abandoned due to various problems. Some of them, although fewer, are performed less frequently than before due to some undesirable results.

There are commonly around 10 classic methods and 4-5 contemporary types.

The most frequently performed primary closure among classic methods is becoming less common because it recurs in about 45-50% of patients. In primary closure, the sinus is removed widely along with healthy skin, and the opening is directly closed.

The open technique has a lower recurrence rate (about 5%), but patients do not prefer it much because the healing time, that is, the time for complete closure, takes 3-6 months. It is the easiest method for the surgeon as there are no stitches or closure.

Flap methods, also known as the flap, have 8-9 types. The sinus is removed, and the gap is closed by sliding the skin from the side (2).

The most successful flap surgery is the D flap. Also known as the Karidakis flap, named after the surgeon who first described it. The skin where the sinus is located is cut in the shape of the letter D, and it is stitched straight, shifting the midline to the side. Asymmetric excision is also called primary suture (3).

In other flap surgeries, the skin is cut into different shapes such as rhomboid flap, Limberg flap, W-Y flap, and gluteal transposition, depending on the cut shape and sliding area.

What Are the Treatment Methods for Ingrown Hair?

The most commonly performed method, and the most successful among contemporary methods, is the micro sinusectomy. It was first developed by doctors at Idea Clinic in 2009, experimented with to determine the ideal format, and the principles of the procedure were declared and published. The procedure allows patients to return to social life or work on the same day, leaves no scars, requires no dressing or wound care, and is the least recurrent method if performed correctly. Due to its high approval by both patients and doctors, it has become increasingly popular.

The most successful of the classic methods is the Karidakis (D flap) method. Unlike other classic methods, it does not require 12-15 days of bed rest; patients can return to work after three days. It leaves minimal scars, causes minimal pain, and has a short dressing period.

Laser Treatment for Ingrown Hair

This is one of the contemporary methods. The inside of the hair mass is emptied with thin forceps-like tools, the inside is scraped with small scrapers called curettes, and the same cleaning procedures are applied to any channels if present. It is washed with serum, and finally, the inside of the sinus and channels are burned with a laser.

From the patient’s perspective, it is as easy as micro sinusectomy, leaves no scars, and allows returning to work on the same day. However, it is more expensive due to the additional cost of laser. Its success is lower compared to micro sinusectomy because the sinus is not completely removed, and it cannot be ensured that the inside is cleaned, which may lead to recurrence of the disease if hairs are left inside due to blind cleaning.

How to Get Rid of Ingrown Hair?

There is no possibility of it resolving on its own, with medications, or similar applications because it is not possible to eliminate the mass under the skin by applying creams or taking pills. The only way to cure the disease is to eliminate the sinus under the skin, and even just eliminating the sinus is not enough; the entry holes of the hairs and, if any, the exit hole must also be eliminated. Without these, true healing cannot be achieved.

Some beauty centers claim they can solve the problem with epilation. This is a completely ignorant approach that aims to take advantage of the patient’s money: even if the area is completely hairless with epilation, the problem under the skin continues.

Can Ingrown Hair Occur on the Legs?

No, structurally, the legs are not prone to this condition. After depilation procedures on the legs, such as laser hair removal, epilady, and waxing, hairs may get confused and grow under the skin. In this case, a situation like a pimple occurs at every point where the hair grows towards the skin surface. This issue is called an “ingrown hair,” and it is a topic unrelated to our discussion. More importantly, when the hairs find their way out, the problem corrects itself, meaning it does not require treatment.

Can Ingrown Hair Occur in the Underarms?

No, there is a similar condition in the armpits, but its formation, course, and treatment are different. This condition, which originates from the hairs in the armpits or, more precisely, their roots, is called “dog’s teat” (hidradenitis suppurativa). Inflammation develops at the root of the hair, and recurring inflammation eventually leads to a tumor-like formation called granuloma and continuous discharge. Hidradenitis suppurativa is discussed under a separate heading.

Can Ingrown Hair Occur on the Penis?

No, ingrown hair does not occur on the penis. However, a disease originating from the hair follicles in the pubic or pubic region, called “folliculitis,” can occur. Sometimes, due to friction, a hair root inflammation called “fronculitis” can also develop. This condition, typically observed in those who perform hair removal with a razor, usually resolves spontaneously without causing any problems.

Can Ingrown Hair Occur in the Belly Button?

Yes, the belly button is the second most common area for ingrown hair. Although it is the second most common area, it constitutes only 1%, making it a very rare condition. Hairs around the belly button, chest hairs, free-floating objects such as environmental skin debris, and clothing dust accumulate in the belly button. Due to the helical structure of the belly button, these foreign objects progress deeper over time. If a person is overweight and does not routinely clean the belly button, these foreign objects accumulating at the bottom can lead to skin and subcutaneous inflammation due to microbial contamination, eventually progressing to abscess formation.

What Should Be Done for an Ingrown Hair Abscess?

Since the time of Hippocrates, the treatment for all abscesses has been approximately the same. Any abscess that has progressed enough to be drained (manifested by the finding called fluctuation during examination) should be drained as soon as possible.

The correct approach is to consult a surgeon, have it drained appropriately, and then use antibiotics.

If not drained, the abscess progresses, thins the skin from a point, and eventually ruptures spontaneously because the body does not tolerate the filth of the abscess and wants to remove it. If left to rupture spontaneously or encouraged to rupture with applications like cooked onions or lozenges, a new and permanent hole may form. Therefore, the abscess should be drained and treated as early as possible.

An abscess causes severe pain and intensifies until it is drained. The patient experiences significant relief once the abscess is drained.

Can an Ingrown Hair be Treated with Cream?

Absolutely not. Cream is a topical application applied to the skin and cannot penetrate beneath the skin, offering no possibility of healing any subcutaneous condition. Although some charlatans may produce creams evoking the name of the disease with cosmetic approval and release them to the market, they have no effect other than being a waste of money. It is nothing more than unnecessary time wasting.

Which Doctor/Specialty to Consult for Ingrown Hair?

Since the disease is close to the anus, it falls under the proctology branch. However, since there are not many proctology specialists in Turkey, general surgery specialists are also knowledgeable in this regard, and they apply all treatment methods.

Here, it is more important to know which methods the specialist knows rather than which specialist to go to.

For example, if you go to a doctor who only performs the Limberg flap, regardless of the condition of your disease, they will perform the Limberg flap. However, if you go to a doctor who knows the micro sinusectomy method and all other methods, they will suggest and apply the most suitable method for you based on the level of your disease. This way, instead of lying face down at home for 12-15 days after a flap operation, you can return to work on the same day.

Does an Ingrown Hair Heal on Its Own?

No, there is no possibility of it healing on its own due to the foreign object under the tissue. Patients often fall into the misconception that the sinus becomes inflamed, is treated by bursting or draining.

When the inflammation subsides, the patient has no complaints, and a patient without complaints does not indicate that their disease has healed. The healing of inflammation does not indicate the healing of the disease.

Once the inflammation and abscess are completely healed, preferably 1.5 – 2 months later, the actual disease should be treated.

Patients tend to postpone treatment because they have healed, which is a faulty approach because it will inevitably become inflamed again one day, and each episode of inflammation elevates the disease one step, leading to the progression of the disease and making the treatment more difficult.

Can Ingrown Hair Be Treated at Home?

Since it is a tissue problem like tooth decay or a sebaceous cyst, there is no possibility of recovery at home with herbal products, medications, or creams. Such efforts can lead to a waste of time and, more importantly, the progression of the disease.

How to Care for the Skin After Ingrown Hair Surgery?

Postoperative care is important, as with all surgical diseases. Since there are more than 15 methods, post-treatment care also varies.

After the most commonly performed microsinusectomy treatment among contemporary methods, there is no need for post-treatment care. The initial dressing is opened after 3 days, and the patient can take a bath. There is no need for further dressing, etc. This is approximately the case for other contemporary methods as well.

For classical surgeries with closure, dressings are changed daily or every two days, and dressings continue for about 2 weeks. Stitches are removed when the wound is completely healed, which can be between 12-20 days.

The open technique does not involve stitching, making it easy for the surgeon, but it is the most cumbersome method for the patient in terms of post-treatment care. Since almost a fist-sized healthy tissue around the sinus is removed, the size of the open wound is naturally palm-sized. Even though the surgeon may say it will close in 1-2 months, it typically takes at least 5-6 months and often longer for complete closure.

Does Ingrown Hair Recur?

After treatment, it is the most frequently recurring surgical disease, with a recurrence probability ranging from 3% to 47% depending on the treatment method.

According to scientific data, the probability of methods recurring is roughly as follows:

  • Microsinusectomy: 3-5%
  • Open technique: 5-6%
  • Flap methods: Approximately 7%
  • Primary closure: 40-50%

Here, the experience and skill of the surgeon performing the method, as well as preventive measures in the subsequent period, are important factors.

How to Prevent Ingrown Hair Recurrence?

Since the cause of the disease is the hair falling from above, if the hairs falling from above are kept away from the buttocks, it will not recur.

The following should be incorporated into the lifestyle:

  • The area should be showered during each bath.
  • Items such as a loofah used for body hygiene should be passed through that area.
  • During every clothing change, underwear should be lowered, and the area should be cleaned by brushing with hands.
  • Underwear should be tucked outside rather than inside the athletic briefs.
  • While cleansing in every toilet use, hands should be passed through the upper buttock area.

All of these actions should be made reflexively without thinking. If the back, waist, shoulders, and that area are very hairy, laser hair removal can be considered.


1- Sebrechts, P. H. (1961). A significant diagnositic sign of pilonidal disease. Diseases of the Colon & Rectum4, 56-59.

2- Khatri, V. P., Espinosa, M. H., & Amin, A. K. (1994). Management of recurrent pilonidal sinus by simple VY fasciocutaneous flap. Diseases of the colon & rectum37(12), 1232-1235.

3- Petersen, S., Aumann, G., Kramer, A., Doll, D., Sailer, M., & Hellmich, G. (2007). Short-term results of Karydakis flap for pilonidal sinus disease. Techniques in coloproctology11, 235-240.

4- Fisher, C., Peters, J. L., & Witherow, R. O. N. (1976). Pilonidal sinus of the penis. The Journal of Urology116(6), 816-817.

5- Dixit, S. P. (1976). Pilonidal sinus of the umbilicus. Canadian Journal of surgery. Journal Canadien de Chirurgie19(5), 422-426.

About Op. Dr. Canan ERDEM

Merhabalar, ben Op. Dr. Canan ERDEM, 1967 doğumluyum 1984 yılında Etiler Anadolu Lisesinden mezun olduktan sonra Cerrahpaşa Tıp Fakültesi’ne girdim ve 1990 yılında mezun oldum. 1991 yılında Erzurum’da mecburi hizmetimi tamamlayarak 2000 yılında Kartal Eğitim Araştırma Hastanesinde Genel Cerrahi Uzmanlığı İhtisasımı tamamladım.