Pilonidal Cyst: Symptoms, Causes & Treatment Guide

What Is a Pilonidal Cyst?

A pilonidal cyst is a sac-like pocket in the skin that forms at the top of the buttock crease (natal cleft), near the tailbone. It typically contains hair, skin debris, and sometimes pus if infected. The term "pilonidal" comes from Latin, meaning "nest of hairs," which accurately describes what is often found inside these cysts.

Pilonidal disease represents a spectrum of conditions ranging from asymptomatic small pits or sinuses to large, painful abscesses. The condition was first described in medical literature in 1833 by Herbert Mayo, though it gained significant attention during World War II when it affected a large number of military personnel, earning it the nickname "Jeep seat disease" due to its association with prolonged sitting in military vehicles.

The natal cleft provides an ideal environment for pilonidal cyst formation. This area naturally traps moisture, heat, and friction—all factors that contribute to hair penetration and subsequent cyst development. The mechanics are straightforward: loose hairs, either from the surrounding skin or shed from elsewhere on the body, become lodged in the skin of the natal cleft. The body recognizes these embedded hairs as foreign objects and mounts an inflammatory response, which leads to the formation of a cyst or sinus tract.

Understanding the nature of pilonidal cysts helps explain why they are notoriously difficult to treat definitively. The sinus tracts that form can be extensive, branching beneath the skin in unpredictable patterns. This is why surgical treatment often requires careful mapping of all sinus tracts to ensure complete removal and reduce the risk of recurrence.

Pilonidal Cyst vs. Pilonidal Sinus

While the terms "pilonidal cyst" and "pilonidal sinus" are often used interchangeably, they technically refer to different stages or presentations of the same disease process. A pilonidal cyst is a closed sac filled with hair and debris, while a pilonidal sinus is a tunnel or tract that connects the cyst to the skin surface. Many patients develop both, with the sinus providing a drainage pathway for the cyst's contents.

A pilonidal abscess occurs when a cyst becomes infected with bacteria, typically Staphylococcus aureus or anaerobic bacteria. This results in a painful, swollen, and often red area that may drain foul-smelling pus. Abscesses require more urgent treatment, usually incision and drainage, before definitive surgical management can be considered.

What Causes Pilonidal Cysts?

Pilonidal cysts are caused by loose hairs penetrating the skin in the natal cleft, triggering an inflammatory response. Risk factors include excessive body hair, prolonged sitting, friction, sweating, and obesity. The condition is most common in young adult males with sedentary occupations or lifestyles.

The exact mechanism by which pilonidal cysts form has been debated for over a century, with two main theories emerging: the congenital theory and the acquired theory. Modern medical consensus strongly favors the acquired theory, which holds that pilonidal disease develops from hairs that penetrate previously normal skin.

Evidence supporting the acquired theory includes the observation that pilonidal cysts virtually never occur before puberty, when body hair development begins. Additionally, the condition has been documented between the fingers of barbers and hairdressers, demonstrating that hair penetration can cause similar problems in other locations. Studies examining the hair found in pilonidal cysts have shown that the hair often lacks root bulbs, suggesting they are broken or shed hairs rather than growing hairs.

The process of hair penetration occurs through a combination of factors. The sharp, pointed tip of a broken hair can drill into the skin, aided by the motion created during walking or sitting. Once embedded, the hair acts as a foreign body, triggering an inflammatory response. The body attempts to wall off the foreign material, forming a granuloma and eventually a cyst. If bacteria enter through the hair follicle opening or along the embedded hair shaft, infection and abscess formation can occur.

Risk Factors for Pilonidal Cysts

Several factors significantly increase the likelihood of developing pilonidal disease. Understanding these risk factors is crucial both for prevention and for explaining why certain individuals are more prone to recurrence after treatment.

Excessive body hair: Having thick, coarse, or abundant hair in the sacrococcygeal region is one of the strongest risk factors. The more hair present, the greater the chance that loose hairs will become embedded in the skin.

Prolonged sitting: Occupations or activities requiring extended periods of sitting, especially on hard surfaces, increase pressure and friction in the natal cleft. This includes truck drivers, office workers, and students who spend long hours seated.

Male sex: Men are two to four times more likely to develop pilonidal cysts than women, likely due to having more body hair and a deeper natal cleft.

Age: The condition primarily affects young adults between 15 and 30 years of age. It becomes increasingly rare after age 40, possibly due to changes in hair growth patterns and the natal cleft anatomy with aging.

Obesity: Excess body weight deepens the natal cleft, increases sweating, and creates more friction in the area, all of which promote pilonidal disease development.

What Are the Symptoms of a Pilonidal Cyst?

Symptoms of pilonidal cyst include pain and tenderness near the tailbone, swelling at the top of the buttock crease, drainage of pus or blood, foul-smelling discharge, redness and warmth over the affected area, and occasionally fever if infection is present. Symptoms may come and go but typically worsen without treatment.

Pilonidal cysts can range from completely asymptomatic small pits to severely painful abscesses that significantly impact daily life. The presentation varies widely depending on whether the cyst is infected, how long it has been present, and the extent of the sinus tract network beneath the skin.

In the early stages, many people with pilonidal disease have no symptoms at all. They may notice small pits or dimples in the skin at the top of the buttock crease, sometimes with visible hairs protruding from them. These pits represent the openings of sinus tracts and are often discovered incidentally during physical examination.

As the condition progresses, most patients begin to experience discomfort. The first noticeable symptom is usually a dull ache or tenderness in the lower back or tailbone area, particularly when sitting for extended periods. This discomfort can be intermittent at first, coming and going over weeks or months.

Signs of Pilonidal Abscess

When a pilonidal cyst becomes infected and forms an abscess, symptoms intensify dramatically. The following signs indicate that an abscess has developed and medical attention should be sought promptly:

• Severe pain: The affected area becomes extremely painful, often making sitting impossible. The pain is typically throbbing and may prevent sleep.
• Swelling: A visible lump develops at the top of the buttock crease. This swelling can range from small to several centimeters in diameter.
• Redness and warmth: The skin over the abscess becomes red, inflamed, and warm to the touch, indicating active infection.
• Discharge: The abscess may spontaneously drain pus or blood-tinged fluid. This discharge often has a foul, unpleasant odor.
• Fever: Some patients develop low-grade fever, indicating systemic response to infection.

How Is Pilonidal Cyst Diagnosed?

Pilonidal cyst is typically diagnosed through physical examination of the natal cleft area. The doctor looks for characteristic pits, sinuses, swelling, and signs of infection. Imaging studies like MRI are rarely needed but may be used in complex or recurrent cases to map the extent of sinus tracts before surgery.

The diagnosis of pilonidal disease is usually straightforward and based primarily on clinical examination. A healthcare provider can typically diagnose the condition by visually inspecting and palpating the sacrococcygeal region. The presence of characteristic midline pits in the natal cleft, with or without associated swelling, drainage, or tenderness, is usually sufficient to confirm the diagnosis.

During the physical examination, the doctor will look for several key features. Midline pits, which appear as small holes in the skin at the top of the buttock crease, are pathognomonic (specifically characteristic) of pilonidal disease. These pits may have visible hairs protruding from them. The examiner will also assess for any swelling, redness, or fluctuance (a wave-like sensation indicating fluid collection) that would suggest an abscess.

The extent of the sinus tract network can sometimes be assessed by gently probing the pits, though this is often deferred until the time of surgery. In some cases, the doctor may express a small amount of discharge from the pits or notice drainage occurring spontaneously, which can help confirm the diagnosis and assess for active infection.

Differential Diagnosis

Several other conditions can mimic pilonidal disease and must be considered during evaluation. Accurate diagnosis is essential because treatment approaches differ significantly between these conditions.

Perianal abscess or fistula: These occur closer to the anus and are typically associated with underlying anal gland infection rather than hair penetration. They may require different surgical approaches.

Hidradenitis suppurativa: This chronic inflammatory skin condition can affect the buttock region and cause similar symptoms. However, it typically involves multiple areas including the armpits and groin, and has a different appearance and course.

Furuncle (boil): A simple skin boil can occur anywhere, including the natal cleft. Unlike pilonidal disease, furuncles don't have the characteristic midline pits and typically resolve with simple treatment.

How Is Pilonidal Cyst Treated?

Treatment for pilonidal cyst depends on severity. Acute abscesses require incision and drainage, while definitive treatment involves surgical excision of the cyst and sinus tracts. Options range from simple excision with open healing to complex flap procedures. Non-surgical treatments like phenol injection or laser therapy may be suitable for some patients.

The management of pilonidal disease has evolved significantly over the years, with multiple treatment options now available. The choice of treatment depends on several factors, including whether an acute abscess is present, the extent of the disease, whether it's a first occurrence or recurrence, patient preferences, and the surgeon's expertise.

Conservative, non-operative management may be appropriate for patients with minimal symptoms or those who are not good candidates for surgery. This approach involves meticulous wound care, regular hair removal from the natal cleft area, and lifestyle modifications such as avoiding prolonged sitting. However, conservative management rarely results in complete resolution and is typically used as a temporizing measure or for patients who decline surgery.

Incision and Drainage

When a pilonidal abscess develops, the first priority is to drain the infected material. Incision and drainage can often be performed in an outpatient setting under local anesthesia. The surgeon makes a small incision over the area of maximum fluctuance, drains the pus, and may loosely pack the wound to promote continued drainage.

This procedure provides rapid pain relief but does not address the underlying pilonidal disease. Approximately 40-50% of patients who undergo incision and drainage alone will experience recurrence and eventually require definitive surgical treatment. For this reason, incision and drainage is considered a temporizing measure rather than definitive treatment.

Surgical Excision

Definitive treatment of pilonidal disease requires surgical excision of the cyst and all associated sinus tracts. Several surgical techniques are available, each with its own advantages and disadvantages regarding healing time, recurrence rates, and time off work.

Excision with open wound healing: The cyst and sinus tracts are completely excised, and the wound is left open to heal from the bottom up (secondary intention healing). This technique has the lowest recurrence rate (5-15%) but requires the longest healing time (6-12 weeks) and daily wound care. It is particularly suitable for complex or recurrent cases.

Excision with primary closure: After excision, the wound edges are sutured together (primary closure). This results in faster healing (2-4 weeks) but has a higher recurrence rate (15-40%) compared to open healing, particularly if the closure is in the midline.

Off-midline closure techniques: These procedures, including the Karydakis procedure and Bascom cleft lift, involve excision followed by closure with the suture line positioned away from the midline. By flattening the natal cleft and moving the scar to one side, these techniques significantly reduce recurrence rates (5-10%) while maintaining relatively short healing times.

Flap procedures: For extensive or recurrent pilonidal disease, various flap procedures such as the rhomboid flap (Limberg flap) or Z-plasty may be used. These techniques bring healthy tissue into the defect and flatten the natal cleft, with recurrence rates typically between 5-20%.

Minimally Invasive Treatments

Several less invasive treatment options have been developed for pilonidal disease, though their long-term effectiveness compared to traditional surgery remains under investigation.

Pit picking (Gips procedure): This involves excising only the midline pits and draining any lateral extensions through small incisions. It has a shorter recovery time but may have higher recurrence rates for extensive disease.

Endoscopic treatment (EPSiT): A newer technique using a specialized endoscope to visualize and treat the sinus tracts from within. Early results are promising, with low recurrence rates and minimal scarring.

Laser treatment: Various laser modalities have been used both to destroy sinus tracts and for hair removal to prevent recurrence. Results are variable, and more research is needed.

What Is the Recovery Like After Pilonidal Cyst Surgery?

Recovery after pilonidal cyst surgery varies by procedure type but typically involves wound care, pain management, activity restrictions, and follow-up appointments. Most patients can return to light activities within 1-2 weeks and full activities within 4-6 weeks. Proper wound care is essential to prevent complications and recurrence.

Understanding what to expect during recovery can help patients prepare appropriately and recognize any concerning developments. The recovery process differs significantly depending on which surgical technique was used, but certain aspects are common to all approaches.

In the immediate postoperative period, most patients experience moderate pain that can be managed with prescribed pain medications. The pain typically decreases substantially within the first few days. Sitting may be uncomfortable for 1-2 weeks, and patients often find sitting on a donut-shaped cushion or lying on their side more comfortable.

Wound care is a crucial aspect of recovery, particularly for procedures involving open wound healing. Patients or their caregivers must learn to clean and dress the wound properly. For open wounds, this typically involves daily or twice-daily packing changes until the wound has healed sufficiently. For closed wounds, dressings may only need to be changed every few days, and showering is usually permitted after 48 hours.

Wound Care After Surgery

Proper wound care significantly impacts healing outcomes and recurrence risk. Here are the key principles:

• Keep the wound clean: Gently clean around the wound with saline solution or as directed by your surgeon during dressing changes.
• Change dressings regularly: Follow your surgeon's instructions for dressing change frequency. Never leave dressings on longer than recommended.
• Monitor for infection: Watch for increasing redness, swelling, warmth, or foul-smelling discharge, and report these signs promptly.
• Keep the area dry: Avoid prolonged exposure to moisture. Pat the area dry after showering once allowed.
• Remove hair from the area: Regular hair removal around the wound edges can prevent new hair penetration during healing.

How Can You Prevent Pilonidal Cyst Recurrence?

Preventing pilonidal cyst recurrence involves keeping the natal cleft clean and hair-free through regular shaving, depilatory creams, or laser hair removal. Avoiding prolonged sitting, maintaining a healthy weight, wearing loose-fitting clothing, and practicing good hygiene are also important preventive measures.

Prevention is a critical aspect of pilonidal disease management, both for those who have never had the condition and for those who have undergone treatment. Since the primary cause is hair penetration, the main preventive strategies focus on reducing hair in the natal cleft area and minimizing factors that promote hair penetration.

Hair removal is the cornerstone of prevention. This can be achieved through several methods, each with its own advantages and disadvantages. Regular shaving or the use of depilatory creams is inexpensive but requires ongoing effort and may cause skin irritation. The area should be kept hair-free not just in the immediate vicinity of any previous surgical site, but throughout the natal cleft region.

Laser hair removal offers a more permanent solution and has been shown in studies to significantly reduce pilonidal disease recurrence. While more expensive upfront, laser hair removal may be cost-effective in the long run by preventing recurrence and the need for additional surgery. Multiple sessions are typically required to achieve adequate hair reduction.

Lifestyle Modifications for Prevention

Beyond hair removal, several lifestyle modifications can help reduce the risk of pilonidal disease development or recurrence:

Avoid prolonged sitting: Take regular breaks to stand and walk if your job requires extended sitting. Use a cushion to reduce pressure on the tailbone area when sitting for long periods.

Maintain a healthy weight: Excess weight increases pressure on the natal cleft and creates a deeper, moister environment that promotes hair penetration.

Practice good hygiene: Keep the natal cleft area clean and dry. Shower daily, especially after sweating, and dry the area thoroughly.

Wear loose-fitting clothing: Tight clothing can increase friction and promote hair penetration. Opt for breathable fabrics and avoid jeans or pants that are tight in the buttock area.

Frequently Asked Questions