Pilonidal Cyst

• pilonidal disease consists of a hair-containing sinus or abscess in the sacrococcygeal area
• This seemingly minor disease process has physicians baffled, as demonstrated by the multiple theories of its etiology and management in the current literature. Congenital and acquired theories of etiology have been proposed. For a time, the entity was referred to as Jeep rider's disease. It caused more than 80,000 US Army soldiers to be hospitalized during WWII and accounted for 4.2 million sick days. Much of the information we have about the disease comes from the military.
• In the US: The frequency is 26 cases per 100,000 population.
• Pilonidal disease has a male predominance; the disease occurs 2.2 times more often in men than women. The male-to-female ratio in patients seeking treatment varies from 3:1 to 7:1.
• The average age of patients at presentation is 21 years. Pilonidal disease usually affects patients in the mid second to fourth decade of life.

Pathophysiology

• Pilonidal disease involves a combination of skin and perineal flora.
  • Staphylococcus aureus is the most common organism.
  • Bacteroides species are the most common anaerobes.
• Risk factors include the following:
  • Male sex
  • Family predisposition
  • Obesity
  • Sedentary lifestyle
  • Repeated trauma
  • Occupation requiring prolonged sitting
• Early theories suggest a congenital cause: that pilonidal sinuses are vestigial structures, cystic remnants of the medullary canal or the result of dermal inclusions caused by faulty development of the median coccygeal raphe.
• It has since been established that pilonidal disease is an acquired condition involving midline pits (enlarged hair follicles) in the natal cleft. It has been suggested that gravity and motion of the gluteal folds create a vacuum that pulls on the follicle. Bacteria and debris enter this sterile area, producing local inflammation. Edema occludes the mouth of the follicle, which continues to expand, rupturing into the underlying fatty tissue. Keratin and pus escape, and a foreign body reaction results in a microabscess, which is similar to perforating folliculitis. The purulent material subsequently tracks within the presacral subcutaneous tissue, producing acute and chronic pilonidal abscesses, as well as potential laterally displaced and epithelialized tracts. The conversion from a microabscess to the burrowing infection defines pilonidal disease; the same forces that create the pits are thought to cause the conversion.
• It was once thought that every pilonidal lesion contained a nest of hair. In reality, only 50% of cysts and sinuses are found to have hair during exploration. This finding, however, does not diminish its importance in the pathophysiology of pilonidal disease.
• Malignant degeneration rarely occurs in pilonidal disease, although verrucous carcinoma (giant condyloma acuminatum) has been described.

History

• Patients with pilonidal disease may seek advice for asymptomatic pits or holes in the natal cleft.
• Most patients seek medical attention for a history of progressive tenderness after physical activity or a period of prolonged sitting, such as during a long drive.
• look like a large pimple at the bottom of the tailbone, just above gluteal cleft
• Acute purulent drainage, pain, and/or swelling may be present.
• Systemic manifestations are rare, but patients may have malaise and fever.
• Twenty percent of symptomatic presentations are a result of an acute pilonidal abscess.
• Eighty percent of symptomatic presentations are exacerbations or manifestations of chronic disease

DDX

• Other Problems to be Considered:
• Perianal abscess arising from the posterior midline crypt
• Simple carbuncle or furuncle
• Osteomyelitis
• Pediatric: Coccygeal sinus (congenital skin adherence to the coccyx)

ED Care

• Asymptomatic pilonidal cysts require only observation and instruction about local hygiene.
• Regarding acute pilonidal abscess, the consensus for conservative outpatient treatment of symptomatic pilonidal disease is growing.
  • Conservative management includes incision and drainage of the abscess or sinus, packing, surgical follow-up, and improved hygiene. This approach leads to good results and low recurrence rates.
  • After the skin is infiltrated with local anesthetic, an adequate incision is made, lateral to the midline, and care should be taken to search for all sinus openings.
  • The contents, including hair and granulations, are evacuated, and then area is irrigated with copious amounts of fluid.
  • Hemostasis is achieved with pressure and packing.
  • Antibiotics are not necessary in most cases and should never be the primary mode of treatment. Antibiotic treatment may supplement incision and drainage in the infrequent case with cellulitis.
• Acute exacerbations of chronic or recurrent disease can be managed in the ED, as described above. Patients with other presentations should be referred for surgical treatment. Surgical treatment for recurrent disease includes the use of advancing flaps, rotational flaps, excision with "marsupialization," grafting, and z-plasty. Preparation for such treatment may include the following steps:
  • Premedication with short-acting benzodiazepine or narcotic (optional).
  • The patient is placed on his or her abdomen.
  • Adequate exposure is achieved by applying tape to hold the buttocks apart and by appropriately lighting the natal cleft.
  • The skin is prepared with Betadine.
  • The area from the anus to the presacrum is shaved carefully.
• Consultations: Consultation with the surgeon in the ED is not necessary unless another disease process, such as a perianal abscess, anal fistula, or osteomyelitis, is suspected.
• (Note: wound vacuum? -JS-)

Further Outpatient Care

• Forty percent of patients return with recurrence of the disease after primary treatment. The high recurrence rate is one of the reasons that definitive management continues to be the subject of debate. Conservative excision of midline pits after initial drainage has been proven to decrease recurrence rates.
• All patients should be discharged from the ED with surgical referrals 1 week after the initial visit. The week allows for the resolution of inflammation and simpler outpatient treatment. Premature skin bridging also has been implicated in sustaining disease.
• Local hygiene, with daily packing and weekly shaving, have been shown to decrease recurrence rates. The primary physician or surgeon can check weekly to ensure appropriate technique.
• Maintenance shaving can be monthly after healing is completed.

Prognosis: The prognosis is excellent with appropriate treatment.

Reference:

E-medicine.com, Update 12/04