Pilonidal Disease Workup

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

Pilonidal disease is diagnosed on the basis of the history and physical examination. The typical location of the midline pits superior to the anus and overlying the sacrum and coccyx is a hallmark of the disease. [10] Occasionally, pilonidal disease can track from a fistula around the anal canal and consequently be confused with anal fistula; however, this is rare. During physical examination, broken hairs can often be extracted from the pilonidal sinus.


Laboratory Studies

Routine laboratory data are not necessary in the treatment of pilonidal disease. Studies should be ordered if warranted by the patient’s medical history and if required for preoperative testing.


Imaging Studies

Imaging studies are not routinely obtained for pinodal disease; however, there have been reports of complicated disease progressing to osteomyelitis, necrotizing fasciitis, toxic shock syndrome, and meningitis. [11]


Histologic Findings

After the onset of puberty, sex hormones affect the pilosebaceous glands, and subsequently, the hair follicle becomes distended with keratin. As a result, a folliculitis develops that produces edema and follicle occlusion.

The infection tracks away from the surface in the trajectory of the occluded follicle. This usually places the tracking follicle approximately 5-8 cm from the anus. In the rarer instance that the sinus is located caudally, it is usually found 4-5 cm from the anus. The laterally communicating sinus overlying the sacrum is created as the pilonidal abscess spontaneously drains to the skin surface. The original sinus tract from the natal cleft becomes an epithelialized tube. The laterally draining tract becomes a granulating sinus tract opening.