Clinical Challenge: Firm Nodule Near Anus

Pilonidal disease is an acquired disorder that may present with a constellation of findings ranging from asymptomatic hair-filled cysts to painful abscesses. The name is derived from the Latin words pilus meaning hair and nidus meaning nest.1 The condition was once referred to as jeep...

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Pilonidal disease is an acquired disorder that may present with a constellation of findings ranging from asymptomatic hair-filled cysts to painful abscesses. The name is derived from the Latin words pilus meaning hair and nidus meaning nest.¹ The condition was once referred to as jeep rider’s disease after thousands of soldiers in World War II were hospitalized with the condition.^1,2

The pathophysiology of the disease is unclear but it is hypothesized that inversion of hair growth leads to a foreign-body reaction resulting in granuloma formation.² The condition is 2 to 3 times more common in men than women. Risk factors include obesity, poor hygiene, coarse hair, prolonged friction, and coexisting hidradenitis suppurativa.³

The diagnosis is often made clinically based on location, identification of risk factors, and physical examination, which may range from pits or dimples at the base of the spine to large tracking sinuses and/or abscesses accompanied by pain, erythema, edema, and foul drainage. Chronic cases may be associated with visible tracks. Histology often reveals cystic cavities containing hair and cellular debris lined with granulation tissue.³

Treatment is divided into operative vs nonoperative management. Patients should be advised to keep the area clean and free of hair using methods such as laser hair removal, shaving, waxing, and depilatory creams. Cysts that are not infected may resolve on their own.³

Persistent and infected cysts require incision and drainage. In cases of acute infection, treatment plans are often staged with the infection addressed first.³ Excising the abscess cavity and thoroughly removing the nest of hair and skin debris has been demonstrated to reduce recurrence and complications from wound healing.⁴ Following wide surgical excision, defects can be closed with skin grafts and local flaps. In cases where primary closure is not a viable option, healing by secondary intent may be facilitated with negative-pressure wound therapy and wound packing.⁵ 

Sara Mahmood, DPM, is a podiatrist who completed a joint dermatology/podiatry fellowship and is on staff at the DermDox Dermatology Centers in Pennsylvania. Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.

References

1. Karydakis GE. Easy and successful treatment of pilonidal sinus after explanation of its causative process. Aust N Z J Surg. 1992;62(5):385-389. doi:10.1111/j.1445-2197.1992.tb07208.x

2. Patey DH, Scarff RW. Pathology of postanal pilonidal sinus; its bearing on treatment. Lancet. 1946;2(6423):484-486. doi:10.1016/s0140-6736(46)91756-4

3. Johnson EK, Vogel JD, Cowan ML, Feingold DL, Steele SR; Clinical Practice Guidelines Committee of the American Society of Colon and Rectal Surgeons. The American Society of Colon and Rectal Surgeons’ clinical practice guidelines for the management of pilonidal disease. Dis Colon Rectum. 2019;62(2):146-157. doi:10.1097/DCR.0000000000001237

4. Doll D, Matevossian E, Hoenemann C, Hoffmann S. Incision and drainage preceding definite surgery achieves lower 20-year long-term recurrence rate in 583 primary pilonidal sinus surgery patients. J Dtsch Dermatol Ges. 2013;11(1):60-64. doi:10.1111/j.1610-0387.2012.08007.x

5. Biter LU, Beck GM, Mannaerts GH, Stok MM, van der Ham AC, Grotenhuis BA. The use of negative-pressure wound therapy in pilonidal sinus disease: a randomized controlled trial comparing negative-pressure wound therapy versus standard open wound care after surgical excision. Dis Colon Rectum. 2014;57(12):1406-1411. doi:10.1097/DCR.0000000000000240