Pilonidal disease

INTRODUCTION — Pilonidal disease is a common condition of the skin and subcutaneous tissue at or near the upper part of the natal cleft of the buttocks. The clinical manifestations, diagnosis, and management of pilonidal disease are presented here.

Pilonidal disease, especially when infected, can be confused with other conditions, which are discussed in other topics (see 'Differential diagnosis' below):

●(See "Cellulitis and skin abscess: Epidemiology, microbiology, clinical manifestations, and diagnosis".)

●(See "Hidradenitis suppurativa: Pathogenesis, clinical features, and diagnosis".)

●(See "Perianal and perirectal abscess".)

ANATOMY — The natal cleft, also called the gluteal cleft, is the groove between the buttocks that extends from just below the sacrum to the perineum, superior to the anus (figure 1). The cleft or sulcus occurs as a result of the anchoring of the deep layers of the skin overlying the coccyx to the anococcygeal raphe. The cleft forms the border between the gluteus maximus muscles, which obscure the cleft when a person is upright (figure 2).

While the natal cleft is the most common site of pilonidal disease, occasionally pilonidal cysts have been noted in other locations such as the umbilicus, scalp, interdigital spaces, and between breasts [1-3]. Others have reported pilonidal sinus occurring in locations that would be subject to local trauma from hair, such as on the hands of barbers, sheep shearers, and dog groomers [4-6].

EPIDEMIOLOGY — The incidence of pilonidal disease is approximately 26 per 100,000 population, with a mean age at presentation of 19 years for women and 21 years for men, with men being affected two to four times more often than women [7-9]. Although pilonidal disease is less frequent in children and adults older than 45 years, it is still encountered in surgical practice in those age groups. Patient presentations are equally divided between acute and chronic disease; few patients present with asymptomatic disease [10].

RISK FACTORS — Risk factors for pilonidal disease include [7,9,11]:

●Overweight/obesity

●Local trauma or irritation

●Sedentary lifestyle or prolonged sitting

●Deep natal cleft

●Increased hair density in the natal cleft region

●Family history

●Stiffer occipital and intergluteal hair [12]

●Polycystic ovary syndrome [13]

Although these are typical risk factors, often none are present in patients with pilonidal disease.

ETIOLOGY — Although pilonidal disease was originally thought to be congenital due to abnormal skin in the gluteal cleft [14], the contemporary theory considers it acquired rather than congenital [1,4-6,15-17]. The tendency of pilonidal disease to recur following an extensive surgical resection and the occurrence of pilonidal cysts in locations other than the natal cleft also supports that theory.

PATHOGENESIS — The specific mechanism for the development of pilonidal disease is unclear, although the presence of hair and inflammation in the natal cleft are contributing factors [7,18,19]. As a person sits or bends, the natal cleft stretches, damaging or breaking hair follicles and opening a pore or "pit." The pores collect debris and serve as a fertile environment for hairs shed from the head, back, or buttocks to lodge and become embedded. As the skin is drawn taut over the natal cleft with movement, negative pressure is created in the subcutaneous space, drawing hairs deeper into the pore, and the friction causes the hairs to form a sinus.

Typically, pilonidal sinus tracts extend cephalad, which is likely related to the mechanical forces involved as the direction of the follicle determines the direction of the sinus tract; however, they can also extend laterally or inferiorly and may resemble anal fistula disease [7,18] (see 'Differential diagnosis' below). Cavities may contain hair, debris, and granulation tissue, but hair follicles are rarely identified on histopathologic examination [17]. Pilonidal cavities are not true cysts and lack a fully epithelialized lining; however, the sinus tracts may be epithelialized (figure 3). Foreign body giant cell reaction is typically associated with local cellular infiltrate.

Once the sinus becomes infected secondarily, an acute subcutaneous abscess develops, spreads along the tract, and may rupture spontaneously, discharging its contents through the skin cephalad or lateral to the natal cleft, or it may require operative drainage (figure 1). A recurring or chronic infection can also develop in the affected area due to retained hair or infected residue [7].

CLINICAL MANIFESTATIONS

Patient presentation — The patient presentation is highly variable, ranging from an asymptomatic pilonidal cavity or sinus to acute infection or chronic inflammation and drainage associated with an open wound of varying size [7,10]:

Acute — Symptoms of an acute exacerbation include sudden onset of mild-to-severe pain in the intergluteal region while sitting or performing activities that stretch the skin overlying the natal cleft (eg, bending, sit-ups). The patient may also report intermittent swelling as well as mucoid, purulent, and/or bloody drainage in the area. Fever and malaise are generally associated with an undrained abscess.

Chronic — Patients with chronic pilonidal disease experience recurrent or persistent drainage and pain. They may identify one or more areas of drainage (sinus tracts). There is no universally accepted way of grading the severity of pilonidal disease. Components of published classification schemes include the number, size, and location of pits/sinuses, tracks, and lesions, presence/absence of abscess, primary versus recurrent disease, and patient characteristics (sex, weight, hirsutum) [20]. Some of these factors may influence the choice of surgical approaches. (See 'Chronic disease' below.)

There have been occasional case reports of squamous cell carcinomas arising in long-standing, neglected pilonidal sinuses [21]. Disease presenting with an unusual or aggressive appearance should be evaluated with a biopsy.

Physical examination — Pilonidal disease is identified by retracting the buttock cheeks enough to visualize the pores or sinuses within the valley of the natal cleft; additional findings may be present depending on the acuity of presentation:

●For asymptomatic patients, the physical examination reveals one or more primary pores (pits) in the midline of the natal cleft and/or a painless sinus opening cephalad and slightly lateral to the cleft (figure 1).

●For patients with acute exacerbation, the examination often reveals cellulitis in the natal cleft and a tender, fluctuant mass in or near the top of the natal cleft, usually slightly lateral to one side, indicating the presence of an abscess.

●For patients with chronic disease, one or more sinus openings draining mucoid, purulent, and/or bloody fluid can be identified (picture 1). A hair may occasionally be seen protruding from a sinus opening [7,10]. Secondary tracts or pits can be identified lateral to the midline in patients with complex disease.

DIAGNOSIS — Asymptomatic pilonidal disease is diagnosed clinically based upon findings of characteristic midline pores (pits) in the natal cleft region. Acute and chronic pilonidal disease can be diagnosed by additional findings of a tender mass and one or more sinus openings draining mucoid, purulent, or bloody fluid, respectively. The diagnosis is clinical; imaging or laboratory studies are not necessary.

DIFFERENTIAL DIAGNOSIS — Differentiating pilonidal disease from an alternative or concurrent disease often requires a thorough anorectal examination.

●Perianal abscess – A perianal abscess often presents with severe pain in the anal or rectal area, and constitutional symptoms such as fever and malaise are common (picture 2). On physical examination, an area of fluctuance or a patch of erythematous, indurated skin overlying the perianal skin may be noted. While perirectal abscesses are generally near the anus, pilonidal abscesses are located more cephalad in the natal cleft area (figure 1). (See "Perianal and perirectal abscess", section on 'Clinical manifestations'.)

●Anorectal fistula – An anorectal fistula is the chronic manifestation of an anorectal abscess. When the abscess ruptures or is drained, an epithelialized tract can form to connect the abscess in the anus or rectum with the perirectal skin. The diagnosis of a fistula is primarily based upon characteristic findings on history and physical examination: pain, purulent drainage, and a perirectal skin lesion. While anorectal fistulas track toward the anus, pilonidal sinuses track toward the cavity in the midline of the natal cleft (picture 3). (See "Anorectal fistula: Clinical manifestations and diagnosis", section on 'Clinical features'.)

●Perianal complications of Crohn disease – Perianal complications of Crohn disease include anal fissures, fistulas, and abscesses. In particular, anal fissures may be asymptomatic or present with bleeding, deep ulceration (picture 4), or anal pain, which may be worsened during evacuation. Symptoms can vary from anal pain and purulent discharge to bleeding and incontinence. The area involved with perianal Crohn disease is generally centered around the anus, rather than the natal cleft area. (See "Perianal Crohn disease".)

●Buttock skin abscess, folliculitis, furuncle, carbuncle – Skin abscesses are collections of pus within the dermis and deeper skin tissues (picture 5). Folliculitis is a superficial bacterial infection of the hair follicles with purulent material in the epidermis (picture 6 and picture 7). A furuncle is an infection of the hair follicle in which purulent material extends through the dermis into the subcutaneous tissue, where a small abscess forms. A carbuncle is a coalescence of several inflamed follicles into a single inflammatory mass with purulent drainage from multiple follicles. Furuncles and carbuncles commonly involve the buttocks (picture 8). These lesions are typically away from the midline and not associated with a sinus tract. (See "Cellulitis and skin abscess: Epidemiology, microbiology, clinical manifestations, and diagnosis", section on 'Skin abscess'.)

●Hidradenitis suppurativa – Hidradenitis suppurativa is a chronic follicular occlusive disease involving the intertriginous skin of the axillary, groin, perianal, perineal, and inframammary regions (picture 9 and picture 10). Hidradenitis suppurativa can occur in the perirectal area and present with purulent drainage. Hidradenitis suppurativa has some characteristics in common with pilonidal disease (eg, sinus tracts, sores), and some have postulated a relationship/common etiology between hidradenitis suppurativa and pilonidal disease [22,23]. However, hidradenitis is usually easily distinguished by its typical location in the perineal or inguinal area, rather than the natal cleft area. (See "Hidradenitis suppurativa: Pathogenesis, clinical features, and diagnosis".)

●Systemic infection – In rare occasions, such as in immunocompromised hosts, systemic infectious processes such as tuberculosis, syphilis, and actinomycosis [24] can involve the intergluteal area and mimic pilonidal disease.

MANAGEMENT — The management of pilonidal disease is variable and depends upon the acuity of presentation and the extent of disease.

Asymptomatic disease — Based upon limited retrospective data, a surgical excision is not typically performed for patients who have never experienced an acute flare of a pilonidal sinus [25]. In a retrospective review of 26 patients with an incidental pilonidal sinus undergoing an excision and primary closure, the rate of healing following excision and primary closure was only 62 percent [25]. Because of the morbidity associated with most procedures performed to address pilonidal disease, surgery should be discouraged in the asymptomatic patient.

Although gluteal cleft hair has been implicated in the pathogenesis of pilonidal disease, it is not known whether gluteal cleft hair removal is beneficial to completely asymptomatic patients.

Acute abscess — An acute pilonidal abscess should be managed with prompt incision and drainage at the time of presentation. Antibiotics cannot be expected to be successful in treating a significant pilonidal abscess. Antibiotic use should be reserved for those with cellulitis in the absence of abscess or in those with an abscess and significant cellulitis after surgical drainage.

Surgical drainage — The incision is generally performed over the area of maximal fluctuance, and all inflammatory debris and visible hair within the abscess cavity should be debrided [7,26,27]. In a randomized trial, unroofing and curettage of the abscess cavity resulted in superior healing (96 versus 79 percent) and fewer recurrences (10 versus 54 percent) compared with drainage alone [28].

Wounds are packed with gauze, and healing occurs by secondary intention in the acute setting. Curettage of the pilonidal sinus and tract or excision of midline pores has no clinical benefit [29] and is not typically performed in the clinical setting of an acute infection [27].

Role of antibiotics — The role of antibiotics is generally limited to the clinical setting of cellulitis [7]. Antibiotic use should be reserved for those with cellulitis in the absence of abscess and for those with significant cellulitis after surgical drainage.

There are no definitive data to support antibiotic therapy in the management of the patient with an acute abscess or chronic pilonidal disease without cellulitis. A systematic review that included 25 randomized trials found a small postoperative healing benefit when perioperative antibiotics were given, but the magnitude of the benefit was modest, the sample sizes were small, and many studies had methodologic limitations [30].

However, patients with underlying immunosuppression, high risk for endocarditis, methicillin-resistant Staphylococcus aureus (MRSA), or concurrent systemic illness should be considered for ancillary antimicrobial prophylaxis in conjunction with surgical management [7]. Antimicrobial prophylaxis in high-risk clinical settings is reviewed separately. (See "Methicillin-resistant Staphylococcus aureus (MRSA) in adults: Treatment of skin and soft tissue infections" and "Acute cellulitis and erysipelas in adults: Treatment".)

The most common organisms isolated in chronic pilonidal disease are aerobes, whereas anaerobes such as bacteroides predominate in abscesses. A reasonable antibiotic choice would be a first-generation cephalosporin (such as cefazolin) plus metronidazole. The management of cellulitis is reviewed separately. (See "Acute cellulitis and erysipelas in adults: Treatment".)

Follow-up care — Following simple incision and drainage for first-episode acute pilonidal abscesses, overall successful healing occurs in approximately 60 percent of patients; the remaining patients will require a second definitive procedure to address excess granulation before wound healing [31]. The recurrence rates reported in the literature ranged from 10 to 55 percent, with the presence of multiple pores and lateral sinus tracts corresponding with higher rates [27,31,32]. (See 'Chronic disease' below.)

Following healing of a drained pilonidal abscess, patients should begin regular gluteal cleft shaving or another method of epilation (eg, laser, depilatory cream [eg, Nair]), as gluteal cleft hair has been implicated in the pathogenesis of pilonidal disease [25,27]. In a retrospective study, meticulous hair control by natal cleft shaving, along with perineal hygiene and limited lateral drainage for abscesses, was credited with reducing hospital stay and total surgical operations compared with surgical alternatives [33].

It is possible to develop recurrent pilonidal abscesses following drainage of an index pilonidal abscess. However, there are no data regarding whether definite excision of all skin pits and tracks that constitute the patient's pilonidal disease is necessary or helpful. Thus, shared decision making is required. Those who accept the risk of having to drain recurrent abscesses once every few years or so, and the risk that the disease extent may increase with each successive infection, can be followed expectantly. Patients who develop abscesses more frequently or have symptoms beyond occasional abscesses require definitive surgery described below.

Chronic disease — Chronic pilonidal disease presents with either recurrent abscesses with intervening periods of healing or one or more persistently draining sinuses that may be associated with a significant nonhealing wound. In either case, the definitive treatment is surgical [7]. However, the decision for surgery should be based on the severity of symptoms as perceived by the patient, rather than any arbitrary criterion such as the number of flareups (algorithm 1).

Limited disease — There is increasing evidence that for limited pilonidal disease, wide local excision of the natal cleft skin is not necessary [34-37]. What constitutes limited as opposed to extensive disease, however, is not universally agreed [20]. Nevertheless, most reports would consider a few (one or two) pits or sinuses at the midline limited disease [38,39].

All minimally invasive treatment of limited pilonidal disease entails removal of the midline pits/sinuses, beyond which various technique diverge. Some treatments also drain/debride secondary tracks or cavities via the pits/sinuses (eg, the Gips technique or endoscopic technique). Other treatments fill the tracks or cavities with either phenol or fibrin glue to obliterate them. Some minimally invasive techniques can be performed in the office under local anesthetics, others are performed in the operating room as day surgery.

●The original Bascom pit-picking procedure excises the pits with a knife [40], while the Gips procedure utilizes trephines (dermatologic skin punches) of various diameters to excise the pits and to debride underlying cavities and tracts [41]. The otherwise healthy skin bridges in between are preserved, thus reducing pain and wound morbidities.

●Video-assisted ablation of pilonidal sinus is a new minimally invasive treatment based on the complete removal of the sinus cavity through a minimal surgical wound [42]. In a small trial against conventional surgical excision, video-assisted ablation achieved fewer wound infections (1.3 versus 7.2 percent), less pain, quicker return to work (1.6 versus 8.2 days), and higher patient satisfaction [43].

●Phenol injection has been used in lieu of surgical excision in selected patients with chronic pilonidal disease. Crystallized phenol solution can be injected into the sinus tract after hairs and debris have been removed as an outpatient procedure. Along with gluteal cleft hair control, one or more applications of phenol had success rates ranging from 60 to 95 percent and few recurrences [44-46]. It has been used in combination with pit excision [47]. Phenol may be difficult to obtain at your institution. If it is used, one must be careful to protect surrounding tissues from coming into contact with the liquid.

●Fibrin glue has been used either as a monotherapy to fill the sinus tract or as an adjunct to surgery to seal the excision bed. However, a Cochrane review failed to find sufficient evidence for its benefit because the studies were small and at high risk of bias [48].

The main advantage of minimally invasive techniques is less pain and shorter time out of work than standard excisional techniques [43,49,50]. The recurrence rate ranges from 8 to 26 percent at between 12 and 120 months after a minimally invasive procedure, which is similar to or higher than standard excisional procedures depending on the study [37].

To minimize recurrence, perineal hygiene and hair removal is emphasized after minimally invasive treatment of limited pilonidal disease as after incision and drainage of a pilonidal abscess, which is already discussed. (See 'Follow-up care' above.)

Extensive disease — The mainstay of operative management for extensive pilonidal disease is the excision of all sinus tracts and skin pores (pits). Some surgeons prefer to excise all pilonidal sinus tracts down to the level of the sacrococcygeal fascia, while others only unroof and debride the tracts without excising them (figure 4). While the optimal technique is debated, there is agreement that normal tissue should be preserved as much as possible to facilitate wound management [7,27,49,51]. Higher volumes of excised tissue have been associated with increased complication and recurrence rates [52]. The value of using methylene blue to identify associated sinus tracts is debatable [7,49,51].

Options of wound management following pilonidal sinus excision generally fall under either primary or delayed wound closure. A primary closure is associated with faster wound healing (15 versus 60 days [53]) and a faster return to work (12 versus 18 days [54]), but a delayed closure is associated with fewer recurrences (5.3 versus 8.7 percent) according to a 2010 Cochrane review of 26 randomized trials including 2530 patients [55].

Delayed wound closure — The open wounds are treated by dressing changes until healed by secondary intention. Options of dressing include (see "Basic principles of wound management", section on 'Wound packing'):

●Alginates

●Hydrocolloids

●Topical antimicrobials

●Foam dressings

●Hydrogels

An alternative method for managing the open wound is the use of negative pressure wound therapy (NPWT), which is perhaps more useful for larger defects. Based on two trials, a 2022 Cochrane review could not be certain if NPWT reduced time to healing or increased healing rate compared with conventional dressing [56]. The same Cochrane review found low‐certainty evidence on the benefit of platelet‐rich plasma from two trials [57] and of Lietofix cream and hydrogel dressings from a single trial [56].

Delayed closure approaches either leave the wound open or marsupialize the skin edges to the sacrococcygeal fascia (figure 5). Proponents of marsupialization believe that it reduces both healing time (compared with open wound) and recurrence rate (compared with primary closure) [58], and thus excision and marsupialization should be the procedure of choice for all pilonidal disease [59,60]. Due to a lack of comparative data, however, whether to marsupialize the wound is the surgeon's decision.

Primary wound closure — Primary wound closure can be accomplished by either midline (figure 6) or off-midline techniques (figure 7) [55,61]:

●Midline primary closure involves simply reapproximating the cut edges of the skin and subcutaneous tissue at the midline with several layers of sutures.

●Off-midline primary closure takes more planning. The initial incision is typically made at a location lateral to the midline, which depends on the planned technique. Following excision or unroofing of the pilonidal sinus tracts, a skin and subcutaneous tissue flap is usually raised to cover the midline defect. The incision is then closed off the midline with several layers of sutures. Off-midline closure is technically more demanding but can cover a wider defect and result in lower tension at the closure. Techniques commonly used to ensure an off-midline closure are discussed below [62].

For patients undergoing a primary wound closure, off-midline (lateral) closure techniques have been associated with fewer overall complications (risk ratio [RR] 0.23, 95% CI 0.08-0.66), fewer infectious complications (RR 0.27, 95% CI 0.13-0.54), shorter healing time (mean difference 5.4 days, 95% CI 2.3-8.5 days), and fewer recurrences (RR 0.22, 95% CI 0.11-0.43) compared with simple midline closure techniques, according to the same meta-analysis discussed above [55].

Techniques of primary off-midline closure — While an off-midline approach to primary closure may be preferred, the optimal procedure has not been identified, despite multiple randomized trials [63,64]. As such, surgeons should choose a technique based on the extent of the resection, presence or absence of infection, and their experience and preference [27,55,58].

The Karydakis flap and Bascom cleft-lift procedure can be used for initial surgical management or for recurrent disease. Rhomboid, V-Y, and other rotational flap reconstructions are typically reserved for patients with more extensive disease or those who have failed simpler operations [8].

●Karydakis flap – The Karydakis flap uses a mobilized fasciocutaneous flap secured to the sacrococcygeal fascia with lateral sutures to achieve an off-midline wound closure (figure 8) [65]. It achieves a recurrence rate of <5 percent and a wound complication rate of 7 to 21 percent, depending on studies [66-68].

●Cleft-lift (Bascom) procedure – This technique also creates a flap-based closure off the midline, which obliterates the cleft [69]. The primary healing rates were 80 to 96 percent, and the recurrence rate was 0 to 17 percent [70-73]. Here is a sample video of this procedure (movie 1). A meta-analysis of six randomized trials comparing Karydakis/Bascom procedures with the Limberg procedure found no difference in recurrence or wound complications rate [74].

●Rhomboid (Limberg) flap – The rhomboid or Limberg flap is a rotational fasciocutaneous flap that permits primary off-midline closure of the wound and flattening of the gluteal cleft (figure 9) [75]. Here is a sample video of this technique (movie 2). Here are two photos of completed rhomboid flaps (picture 11 and picture 12). The reported recurrence rate (0 to 6 percent) and surgical infection rate (0 to 6 percent) are both low and compare favorably with those of simple midline closure in some studies [76-78].

●V-Y advancement flap – A V-Y advancement flap is another technique of excising pilonidal disease and closing the wound defect (figure 10). Healing rates of >90 percent and low recurrence rates have been reported in case series [79,80].

●Z-plasty – Pilonidal sinuses can be excised and the defect reconstructed using a standard Z-plasty (figure 11 and figure 12). Here is a photo of pilonidal disease successfully treated with Z-plasty (picture 13). The rationale and technique of Z-plasty is discussed elsewhere. (See "Z-plasty" and "Overview of flaps for soft tissue reconstruction", section on 'Introduction'.)

For patients who have primary wound closure, a drain may be used on a case-by-case basis at the surgeon's discretion. Drains have been shown to reduce the incidence of wound complications such as fluid collections but not impact wound infection or recurrence rates [66,81,82]. Drain use should likely be based on the size of the flap utilized and the amount of potential dead space left after reconstruction. Drain removal is based upon surgeon judgment but can often be done after drains produce 20 mL or less for two consecutive days.

There is evidence that razor hair shaving or laser epilation may increase the risk of recurrence following definitive surgery for pilonidal disease [83,84]. Therefore, the hair removal practice recommended after either incision and drainage of a pilonidal abscess or minimally invasive treatment of limited pilonidal disease does not necessarily apply to patients who have undergone an excisional procedure for more extensive pilonidal disease.

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Pilonidal cyst (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Epidemiology – Pilonidal disease is a condition involving the skin and subcutaneous tissue at or near the upper part of the natal cleft between the buttocks. It is most commonly seen in patients in their late teens and early twenties, with a male predominance. It is less frequently seen in children and in those older than 45 years. (See 'Introduction' above and 'Anatomy' above and 'Epidemiology' above.)

●Clinical presentation and diagnosis – The clinical presentation is highly variable, ranging from an asymptomatic pilonidal sinus to an acute infection or chronic exacerbation with inflammation and drainage. The physical findings include one or more primary pores (pits) in the midline of the natal cleft with or without a painless sinus opening(s) cephalad and slightly lateral to one side (figure 1). For patients with acute or chronic disease, a tender mass or sinus draining mucoid, purulent, and/or bloody fluid can be identified. Diagnosis is clinical without the need for laboratory or imaging studies. (See 'Clinical manifestations' above and 'Diagnosis' above.)

●Treatment – Patients who have a pilonidal sinus but have never experienced an acute flare do not require treatment; the treatment of others depend on the acuity of the presentation (algorithm 1) (see 'Management' above):

•Acute abscess – An acute pilonidal abscess is managed with prompt incision and debridement of all inflammatory debris and visible hair within the abscess cavity. Antibiotics are not routinely required without cellulitis. (See 'Acute abscess' above.)

•Chronic disease – Patients with chronic symptoms (eg, pain, drainage) require treatment tailored to the severity of their diseases (see 'Chronic disease' above):

-Limited disease – For patients with one or two pits/sinuses at midline, we suggest minimally invasive treatment, which includes removal of the midline pits/sinuses and debridement of the tracks (Grade 2C). Phenol or fibrin glue may also be injected to obliterate the tracks. (See 'Limited disease' above.)

-Extensive disease – Patients who have more extensive disease require excision of all sinus tracts and skin pores (pits), followed by wound management. (See 'Extensive disease' above.)

●Wound management – Following excision of pilonidal disease, options include leaving the wound open or marsupialization versus primary wound closure. A primary closure is associated with faster wound healing and a faster return to work, but a delayed (open) closure is associated with fewer recurrences. (See 'Delayed wound closure' above.)

•For patients undergoing a primary wound closure, we recommend an off-midline (lateral) closure rather than a midline closure (Grade 1B). Off-midline closures reduce complication rate, healing time, and recurrence rate compared with midline closure. (See 'Primary wound closure' above.)

•For off-midline primary closure, the Karydakis flap and Bascom cleft-lift procedure can be used for initial surgical management or recurrent disease. Rhomboid, V-Y, and other rotational flap reconstructions are typically reserved for patients with more extensive disease or those who have failed simpler operations. (See 'Techniques of primary off-midline closure' above.)

●Hair removal to prevent recurrence – Following healing of a drained pilonidal abscess or minimally invasive treatment of limited disease, patients should begin regular gluteal cleft shaving or another method of epilation (eg, laser, depilatory cream [eg, Nair]), as gluteal cleft hair has been implicated in the pathogenesis of pilonidal disease. By contrast, there is evidence that hair removal may increase the risk of recurrence following definitive surgery for pilonidal disease, and it is not known whether hair removal is beneficial to completely asymptomatic patients. (See 'Follow-up care' above.)