Pilonidal Disease Clinical Presentation

Updated: Mar 16, 2023
  • Author: M Chance Spalding, DO, PhD; Chief Editor: John Geibel, MD, MSc, DSc, AGAF  more...
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History and Physical Examination

Although pilonidal disease may manifest as an abscess, a pilonidal sinus, a recurrent or chronic pilonidal sinus, or a perianal pilonidal sinus, the most common manifestation of pilonidal disease is a painful, fluctuant mass in the sacrococcygeal region.

Initially, 50% of patients first present with a pilonidal abscess that is cephalad to the hair follicle and sinus infection. Pain and purulent discharge from the sinus tract are present 70-80% of the time and are the two most frequently described symptoms. In the early stages preceding the development of an abscess, only a cellulitis or folliculitis is present. The abscess is formed when a folliculitis expands into the subcutaneous tissue or when a preexisting foreign body granuloma becomes infected.

The diagnosis of a pilonidal sinus can be made by identifying the epithelialized follicle opening, which can be palpated as an area of deep induration beneath the skin in the sacral region. These tracts most commonly run in the cephalad direction. When the tract runs in the caudal direction, perianal sepsis may be present.

The distinctions among pilonidal disease, fistula-in-ano, and hidradenitis can be difficult to discern. In the differential diagnosis, also include skin furuncle, syphilitic granuloma, tubercular granuloma, and osteomyelitis of the underlying sacrum with a draining sinus.

Recurrent pilonidal disease is most often observed after incision and drainage of a pilonidal abscess. In this setting, the pilonidal sinus has not been excised and remains after the abscess cavity heals, only to precipitate a recurrence. After surgical excision, the hair follicle has been removed and is no longer the precipitating cause of the chronic pilonidal sinus. Instead, the base of the unhealed surgical wound is believed to become filled with granulation tissue, hair, and skin debris, which is a nidus for the ongoing foreign body reaction that causes the chronic disease.

Endoanal pilonidal sinus is a rare variety of pilonidal disease that affects the perianal skin directly or may occur circumferentially around the anus, involving the skin of the anal verge. [9]  Three causes of perianal pilonidal disease have been described, as follows:

  • First, the pilonidal sinus may tract down caudally, creating a perianal fissure or fistula communicating with the anal canal
  • Second, hair may enter the healing wound of a surgically managed fistula-in-ano
  • Third, hair may be propelled, penetrating the normal anoderm and producing a similar foreign body reaction, which is usually observed in the sacrococcygeal region