Pilonidal disease

INTRODUCTION — 

Pilonidal disease is a suppurative condition of the skin and soft tissue involving the sacrococcygeal cleft (sometimes referred to as the natal or gluteal cleft). It is an inflammatory condition that can be acute or chronically recurrent, and this condition may result in soft tissue infections, most often in the form of an abscess. Pilonidal disease is a common reason for seeking medical attention and can be a source of chronic debilitation due to symptoms of pain and drainage that diminish quality of life and interfere with activities of daily living. The clinical manifestations, diagnosis, and management of pilonidal disease are presented below.

Pilonidal disease 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 sacrococcygeal, or natal, cleft is an intertrigonal groove extending from the sacrum to the cephalad aspect of the perianal region (figure 1). This 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 site of pilonidal disease, there are reports of skin manifestations similar to pilonidal disease in other locations such as the umbilicus, scalp, interdigital spaces, and folds surrounding the 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]. These infrequent presentations suggest that local skin trauma, including from hair, may play a role in the etiology of pilonidal disease. (See 'Etiology and pathogenesis' below.)

Pilonidal disease is characterized by subdermal sinuses that are lined with granulation tissue, and that may communicate with subdermal potential spaces that may contain collections of hair and keratinous debris, in addition to granulation tissue [7-9]. Pilonidal cavities are not true cysts as they lack an epithelialized lining; these spaces serve as a nidus for abscess formation, and as a chronic source of discomfort, given that they come to be colonized by bacteria which leads to either chronic inflammation or an abscess (figure 3). Sinus tracts can extend in any direction from the natal cleft, and these can occasionally be mistaken for an anal fistula if they extend posteriorly toward the postanal space.

EPIDEMIOLOGY — 

The exact incidence of pilonidal disease is difficult to determine, given that the disease is not screened for and thus its discovery relies on a patient presenting with symptomatic disease. One study suggests that the incidence of pilonidal disease is 70,000 cases per year in the United States [10]; other series have estimated that the disease has a mean age of presentation of 19 years for females and 21 years for males, with males being affected two to four times more frequently than females [7,10,11]. Pilonidal disease is less frequent in children and in adults older than 45 years. Patient presentations are equally divided between acute and chronic disease, with few presenting with asymptomatic disease [12].

RISK FACTORS — 

Risk factors for pilonidal disease include [7,10,13]:

●Overweight/obesity

●Local trauma or irritation

●Sedentary lifestyle or prolonged sitting

●Deep natal cleft

●Hirsute natal cleft

●Family history

●Stiffer hair follicles [14]

●Polycystic ovary syndrome [15]

Although these are typical risk factors, patients with none of these risk factors may still present with pilonidal disease.

ETIOLOGY AND PATHOGENESIS — 

There has been controversy as to whether pilonidal disease is an acquired or congenital condition.

●The more accepted hypothesis is that pilonidal disease is acquired due to higher skin temperatures, moisture from sweat, and local trauma to hirsute skin in the natal cleft [8,16]. The convergence of these conditions can potentially create inflammation leading to the development of subdermal nests and tracts of granulation tissue akin to a foreign body reaction. Negative pressure caused by sitting and walking exerted on damaged hair follicles can also draw hair deep into the skin. This theory is supported by recurrent pilonidal disease despite extensive surgical resection of natal cleft tissue, and by the occurrence of skin inflammation in locations other than the natal cleft where local trauma due to hair is encountered. (See 'Anatomy' above.)

●Others have argued that a congenital malunion of the midline sacrococcygeum is the cause of pilonidal disease. Within this paradigm, the treatment would involve surgical intervention to remove abnormal embryological remnants represented by subdermal nests of granulation tissue. Some studies reported that pilonidal disease can occur among multiple members of the same family, which raised the possibility of a genetic basis for pilonidal disease [17,18].

CLINICAL MANIFESTATIONS

Patient presentation — Patient presentation is highly variable, ranging from an asymptomatic examination finding of a pilonidal pit or sinus, to the presence of the same but accompanied by discomfort and drainage, to a chronic, granulation-tissue bearing wound occupying the midline natal cleft [7,12]:

Acute — Symptoms of an acute exacerbation include sudden onset of natal cleft discomfort. This discomfort can occur while sitting, and it is frequently exacerbated by performing a wide number of activities that stretch the skin of the natal cleft. Complaints can also include soft tissue induration, as well as a discharge that is most frequently serosanguinous or purulent. Fever and malaise are generally associated with either a soft tissue infection such as cellulitis or an undrained abscess.

Chronic — Patients with chronic pilonidal disease experience recurrent or persistent drainage and/or pain. They may identify one or more areas of drainage (sinus tracts). 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) [19]. Although some of these factors may influence the choice of surgical approaches, none of these schemes has been widely adopted for clinical use. (See 'Chronic disease' below.)

There have been occasional case reports of squamous cell carcinomas arising in long-standing, neglected pilonidal sinuses [20,21]. While this is exceedingly rare, the treating clinician should remember that chronic inflammation from any cause is a risk factor for malignant transformation. Patients presenting with any unusual skin finding should undergo a biopsy to exclude the rare development of squamous cancer.

Physical examination — Pilonidal disease is identified by exposing the natal cleft, allowing visualization of midline natal cleft sinuses, and, possibly, larger midline skin defects that contain granulation tissue.

●For asymptomatic patients, the physical examination reveals one or more primary pits in the midline of the natal cleft. Less commonly, a painless sinus opening may be noted, though this is usually associated with some degree of drainage (figure 1).

●For patients with acute-onset complaints, the examination often reveals cellulitis in the natal cleft, consistent with inflammation and a possible infection. If an abscess is present, a tender, indurated, or fluctuant region will also be observed.

●For patients with chronic complaints, one or more sinuses will typically be present. Drainage is a frequent and recurrent complaint, most often with a purulent or serosanguinous character (picture 1). Hair may be observed protruding from a sinus opening [7,12].

DIAGNOSIS — 

Asymptomatic pilonidal disease is diagnosed clinically based on findings of characteristic midline natal cleft pits. Acute and chronic symptomatic disease is established by visualizing midline pits accompanied by additional findings, such as an infection (ie, erythema, induration, fluctuance) or chronic drainage associated with one or more sinus openings. Imaging or laboratory studies are generally not necessary.

DIFFERENTIAL DIAGNOSIS — 

Differentiating pilonidal disease from an alternative or concurrent disease requires a thorough examination and an understanding of natal cleft and anorectal anatomy.

●Perianal abscess – A perianal abscess often presents with severe pain in the perianal region, and constitutional symptoms such as fever and malaise are common (picture 2). Physical examination reveals the site of infection within the 5 cm circumference surrounding the anal orifice, a region known as the anal margin. Pilonidal-related infections, including abscesses, will not involve the anal margin. Pilonidal abscesses are always located in the natal cleft area (figure 1). (See "Perianal and perirectal abscess", section on 'Clinical manifestations'.)

●Anal fistula – An anal fistula is the chronic manifestation of a cryptoglandular abscess. The diagnosis of an anal fistula is established on physical examination, revealing a fistula orifice within the anal margin, with associated symptoms that can include discomfort and drainage that can vary between serosanguinous and purulent. Manifestations of pilonidal disease will not involve the anal margin (picture 3). (See "Anorectal fistula: Clinical manifestations and diagnosis", section on 'Clinical features'.)

●Perianal Crohn disease – Perianal Crohn disease includes abscesses and fistulas, though the pathogenesis of these abscesses and fistulas differs from the more common cryptoglandular variety (picture 4). Symptoms attributable to perianal disease are virtually identical to abscesses and fistulas unrelated to inflammatory bowel disease, though, in Crohn patients, these perianal signs and symptoms can be accompanied by other complaints related to inflammation of the rectum, the colon, and the small bowel. Perianal Crohn disease, as the name implies, involves the perianal region rather than the natal cleft area. (See "Perianal Crohn disease".)

●Skin abscess, folliculitis, furuncle, carbuncle – Skin abscesses are collections of pus within the dermis and subdermal 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, leading to abscess formation. A carbuncle is a coalescence of several inflamed follicles into a single inflammatory mass with purulent drainage from multiple follicles. Furuncles and carbuncles can involve the gluteal skin (picture 8). These lesions can be differentiated from pilonidal infections by their distance from the midline. (See "Cellulitis and skin abscess: Epidemiology, microbiology, clinical manifestations, and diagnosis", section on 'Skin abscess'.)

●Hidradenitis suppurativa – Hidradenitis suppurativa is a chronic inflammatory condition of the skin that is characterized by painful subcutaneous nodules that can rupture and spur the development of subdermal abscesses and sinus tracts. Its distribution can include the axillary, inguinal, and perineal regions (picture 9 and picture 10). Hidradenitis suppurativa has some characteristics in common with pilonidal disease such as draining sinus tracts and abscesses, and some have postulated a 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 gluteal region. Despite the unlikely involvement of the natal cleft, these patients will have historical and laboratory features that will allow these conditions to be differentiated from pilonidal disease.

NONSURGICAL MANAGEMENT FOR INACTIVE DISEASE — 

In clinical practice, it is rare to encounter patients with pilonidal disease who do not have any symptoms or prior episodes of flare ups. Most with inactive pilonidal disease have had one or more episodes of previous episodes (eg, abscess or drainage), but the disease is presently quiescent.

Due to the morbidity associated with most procedures performed to address pilonidal disease, we suggest against surgery for patients who have no symptoms from a pilonidal sinus. 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].

In patients with inactive pilonidal disease, however, there may be a role for the removal of hair from the natal cleft, either by shaving or laser epilation, provided that there is no soft tissue infection present [26]. While there is only low-quality evidence supporting hair removal, the approach is low-cost, easy to implement, and associated with minimal risk of complications. Additionally, it targets a potential contributing factor to the disease: excess hair in the natal cleft.

Improved hygiene, hair removal, and lifestyle modification have been associated with a decrease in disability days and the need for operation [27]. There is also evidence that improved hygiene and regular shaving reduce recurrence rates after operative interventions such as trephination or excision [28].

Epilation techniques with either laser or intense pulse light may be more effective than shaving and chemical hair removal because they remove the hair shaft, follicle, and bulb. In a small randomized trial, laser epilation reduced the one-year recurrence rate from 34 to 10 percent [29]. However, there was no statistically significant reduction in emergency room or hospital visits or surgical procedures, and laser epilation requires more resources.

Phenol or fibrin glue has been injected into pilonidal sinus tracts as a primary treatment [30-32]. There is no high-quality evidence that either is as effective as more established surgical treatments such as trephination or excision [33].

SURGICAL MANAGEMENT FOR ACTIVE DISEASE — 

The surgical management of pilonidal disease is variable and depends on the presence or absence of an infection (algorithm 1).

Abscess — For most patients with a pilonidal abscess, we suggest prompt incision and drainage at the time of presentation.

Surgical drainage — The incision is generally performed over the area of maximal fluctuance. In general, a smaller incision is adequate if a drain is placed to prevent premature closure of the incision site. This approach is also helpful in avoiding the need for patient-directed wound care such as wound packing.

If a larger incision is deemed necessary, this often requires an operating room setting with a general anesthetic. In these circumstances, the removal of inflammatory debris and visible hair may be appropriate [7,34,35]. In one 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 [36]. Larger wounds are typically treated with saline gauze wet-to-dry dressings, with healing by secondary intention.

Role of antibiotics — Antibiotics would only be adequate for the treatment of diminutive (<3 cm) collections. For abscesses treated with drainage, antibiotics are not required unless there are systemic symptoms of infection, such as fevers, extensive cellulitis, or the patient is immunocompromised, including poorly controlled diabetes [26]. 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 the healing of a drained pilonidal abscess, we suggest regular gluteal cleft shaving or another method of epilation (eg, laser). (See 'Nonsurgical management for inactive disease' above.)

It is possible to develop recurrent pilonidal abscesses following drainage of an index pilonidal abscess. 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 [26,35,37]. (See 'Chronic disease' below.)

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 to prevent recurrence. Patients who develop recurrent abscesses should be counseled regarding definitive surgery after their infection has been resolved. (See 'Chronic disease' 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 nonhealing wound. In either case, the definitive treatment is surgical [26]. However, the decision for surgery should be based on the severity of symptoms as perceived by the patient and the impact of those episodes on the patient's quality of life, rather than on arbitrary criteria such as the number of episodes (algorithm 1).

Limited disease — There is increasing evidence that for limited pilonidal disease, wide local excision of the natal cleft skin is not necessary [26,33,38-40]. What constitutes limited as opposed to extensive disease, however, is not universally agreed [19]. Nevertheless, most reports would consider a few (one or two) pits or sinuses without significant lateral extension as limited disease [40-42].

All minimally invasive treatment of limited pilonidal disease entails removal of the midline pits/sinuses, beyond which various techniques diverge. Some treatments also drain/debride secondary tracks or cavities via the pits/sinuses (eg, the Gips procedure 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.

●Pit-picking procedures (eg, Bascom I procedure, Gips procedure) – The original Bascom pit-picking procedure excises the pits with a knife [43], while the Gips procedure utilizes trephines (dermatologic skin punches) of various diameters to excise the pits and debride underlying cavities and tracts [44]. The otherwise healthy skin bridges in between are preserved, thus reducing pain and wound morbidities (figure 4). Trephination has been reported to have healing rates of approximately 90 percent, with recurrence rates of 16 percent [45]. Advantages of this technique include small incisions, the absence of wound packing as the patient's responsibility, and the ease of repeating this procedure or another type of surgery should recurrences develop.

●Video-assisted ablation of pilonidal sinus is a minimally invasive treatment based on the complete removal of the sinus cavity through a minimal surgical wound [46]. In a small trial comparing this endoscopic technique with 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 [47].

●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; phenol creates a caustic reaction without creating pain given that the phenol solution can have analgesic effects. Further, phenol denatures hair that likely contributes to pilonidal disease. After debriding the tract, 1 to 3 mL of phenol is instilled, protecting the surrounding skin with ointment. Often, more than one session is required to achieve good results. Along with gluteal cleft hair control, one or more applications of phenol had success rates ranging from 60 to 95 percent and few recurrences [48-50]. It has been used in combination with pit excision [51] or with laser epilation [49]. Depending on the patient and the number of sinuses, phenol can be administered in a clinic setting without sedation.

●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 did not find sufficient evidence for its benefit because the studies were small and at high risk of bias [52].

The main advantage of minimally invasive techniques is less pain and faster recovery compared with excisional techniques [47,53,54]. In two meta-analyses, the recurrence rates were similar for both minimal surgical interventions and the more extensive procedures, which ranged from 1 to 8.5 (interquartile range 1.9 to 2.8) percent after minimal surgical techniques, and from 0.2 to 5 (1 to 2.8) percent after more extensive surgery [55,56]. There was a substantial increase in recurrence with time after all procedures.

Extensive disease — The mainstay of operative management for extensive pilonidal disease is the excision of all sinus tracts, which includes all subdermal granulation tissue. Some surgeons prefer to extend the depth of their excision to the investing fascia of the sacrum (figure 4); while this may be necessary for certain distributions of disease, it also creates a larger wound. In some circumstances, a lesser debridement that unroofs sinus tracts without excision may be employed (ie, the lay-open or deroofing techniques) [57,58]. While the optimal technique is debated, there is agreement that normal tissue should be preserved as much as possible to facilitate wound healing, as higher volumes of excised tissue have been associated with increased rates of wound failure [59]. The value of using methylene blue to identify associated sinus tracts is debatable and based on low-quality data [60,61].

Traditionally, options for wound management without a flap would include either primary closure or wound healing by secondary intention. A primary closure is associated with faster wound healing (eg, 15 versus 60 days [62]) and a faster return to work (eg, 12 versus 18 days [63]), but a delayed closure is associated with 35 percent fewer recurrences (5.3 versus 8.7 percent) according to a 2010 Cochrane review of 26 randomized trials including 2530 patients [64].

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

●Alginates

●Hydrocolloids

●Topical antimicrobials

●Foam dressings

●Hydrogels

The surgeon may choose any dressing, as a 2022 Cochrane review of 11 trials did not find any high-certainty evidence that any of the dressings or topical agents had a benefit on time to wound healing or the proportion of wounds that heal at a specific time point [65].

An alternative method for managing the open wound is the use of negative pressure wound therapy (NPWT), perhaps best reserved for very large defects. However, the Cochrane review could not be certain if NPWT reduced time to healing or increased wound healing rates compared with conventional dressings based on two trials [65].

The same Cochrane review also found low‐certainty evidence on the benefit of platelet‐rich plasma from two trials [66]. A subsequent trial found benefits in using platelet-rich plasm as an adjunct to phenol in children [67].

Delayed closure techniques may 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 a completely open wound) and recurrence rates (compared with primary closure) [68-70]. Due to a lack of high-quality comparative data, however, neither technique can be declared to be the superior choice.

Primary wound closure — Primary wound closure can be accomplished by either midline (figure 6) or off-midline techniques (figure 7) [64,71]:

●Midline primary closure involves reapproximating the edges of the skin and subcutaneous tissue in the midline, usually using several layers of sutures.

●Off-midline primary closure requires more planning. The initial incision is typically made at a location lateral to the midline, with its location dependent on the closure technique. Following excision or unroofing of the pilonidal sinus tracts, a skin and subcutaneous tissue flap is 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 may result in less tension at the suture line. Techniques commonly used to ensure an off-midline closure are discussed below. (See 'Techniques of primary off-midline closure' below.)

For patients undergoing a primary wound closure, we recommend an off-midline (lateral) closure rather than a midline closure. Off-midline (lateral) closure techniques have been associated with less wound dehiscence (3.9 versus 8.9 percent), fewer infectious complications (3.8 versus 11.7 percent), shorter healing time (mean difference 5.2 days, 95% CI 2.9-7.6 days), and fewer recurrences (1.5 versus 6.8 percent) compared with simple midline closure techniques, according to a Cochrane meta-analysis of 33 trials [72].

Techniques of primary off-midline closure — While an off-midline approach to primary closure is preferred, the optimal procedure has not been identified, despite multiple randomized trials [73,74]. As such, surgeons should choose a technique based on the extent of the resection and their experience [35,64,68].

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 [11].

●Karydakis flap – The Karydakis flap involves excising diseased tissue with an elliptical surgical site, with the cephalad and caudal edges of the wound being 2 cm off midline. A fasciocutaneous flap is then mobilized from the contralateral aspect of the natal cleft, covering the wound with an off-midline wound closure performed in several layers (figure 8) [75]. It achieves a recurrence rate of <5 percent and a wound complication rate of 7 to 21 percent, depending on studies [76-78].

●Cleft-lift (Bascom) procedure – This technique "lifts" the normally concave natal cleft, creating an off-midline suture line, obliterating the cleft [79]. Literature on this technique describes marking a "safety zone" defined by where the gluteal tissues are able to contact one another after the gluteal cleft is brought together. The diseased tissue is excised, raising a flap from one side of the cleft that is brought to the contralateral side to cover the soft tissue defect. The primary healing rates were 80 to 96 percent, and the recurrence rate was 0 to 17 percent [80-83]. 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 [84].

●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) [85]. 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 in several studies compare favorably with those of simple midline closure [86-88].

●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 [89,90].

●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 [76,91,92]. Drain is best based on the size of the flap utilized and thus the volume of potential dead space following reconstruction. Drain removal is based upon surgeon judgment but is typically safe once drains produce 20 mL or less for two consecutive days.

Hygiene involving hair removal is generally recommended after surgical excision of pilonidal disease to prevent recurrence (see 'Nonsurgical management for inactive disease' above). However, studies of using laser epilation adjunctively after surgical excision of pilonidal disease reported discordant results [29,93], possibly due to heterogeneity in disease severities and nonstandardized definition of recurrences [94].

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 suppurative condition involving the skin and subcutaneous tissue at or near the upper part of the natal cleft between the buttocks. It is most 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.)

●Inactive disease – For patients who have a pilonidal sinus but no active symptoms, we suggest regular gluteal cleft shaving or another method of epilation (eg, laser), rather than any surgical treatment (Grade 2C). This approach is low cost, low risk, easy to implement, and addresses cleft hair, which has been implicated in the pathogenesis of pilonidal disease. Surgical excision of pilonidal disease can potentially lead to significant wound morbidities. (See 'Nonsurgical management for inactive disease' above.)

●Active disease – Patients with active symptoms from pilonidal disease require surgical treatment, the extent of which depends on the acuity and severity of their presentation (algorithm 1) (see 'Surgical management for active disease' above):

•Acute abscess – Most patients with a pilonidal abscess require prompt incision and drainage at the time of presentation. Antibiotics are not required unless there are systemic symptoms of infection such as fevers, extensive cellulitis, or the patient is immune suppressed including poorly controlled diabetes. (See 'Abscess' above.)

•Chronic disease – Patients with chronic symptoms (eg, pain, drainage) require surgical excision tailored to the extent of their diseases (figure 4) (see 'Chronic disease' above):

-Limited disease – For patients with one or two pits/sinuses at midline, we suggest minimally invasive treatment rather than full excision (Grade 2C). Minimally invasive treatment only removes the midline pits/sinuses and debrides, rather than excises the sinus tracks. 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 full 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 (secondary intention)' 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 rates, healing time, and recurrence rates 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.)

ACKNOWLEDGMENT — 

The UpToDate editorial staff acknowledges Eric K Johnson, MD, FACS, FASCRS, who contributed to earlier versions of this topic review.