Pilonidal Sinus

AUTHORS:
Stephanie Ryan, MD • Phillip Jenkins • Gabrielle Young

AFFILIATIONS:
University of Florida College of Medicine, Gainesville, Florida

CITATION:
Ryan S, Jenkins P, Young G. Pilonidal sinus. Consultant. 2020;60(12):27-28. doi:10.25270/con.2020.06.00008

Received February 18, 2020. Accepted May 14, 2020.

DISCLOSURES:
The authors report no relevant financial relationships.

CORRESPONDENCE:
Stephanie Ryan, MD, Assistant Professor, Division of General Pediatrics, University of Florida College of Medicine, 7046 SW Archer Rd, Gainesville, FL 32608 (sfryan@ufl.edu)

A 16-year-old African American adolescent presented to his pediatrician’s office with concern for itching and discharge from a dimple on his right lower back (Figures 1 and 2).

Figure 1. A dimple on the right lower back of a 16-year-old boy.

Figure 2. Close-up view of the dimple on the patient’s back.

History. The dimple had been present since birth, according to the boy’s mother, and it had never before caused the patient discomfort. At presentation, the dimple had been pruritic for approximately 3 weeks. Several days prior to presentation, the patient had observed an initially clear discharge from the dimple; the discharge had turned purulent 2 days prior to presentation. He denied any significant pain. The family noted no new exposures, travel, or trauma to the area. His medical history was otherwise not significant, and he had no major allergies and was up-to-date on all immunizations.

Physical examination. The patient was afebrile, and vital signs were normal. He was in no acute distress. On skin examination, a dimple was noted on the right side of the lower back, just above the posterior superior iliac crest. No erythema, fluctuance, or induration were present. Pressure from the superior aspect of the dimple produced a foul-smelling purulent discharge. He had mild tenderness to palpation in the area. The rest of the physical examination findings were unremarkable.

The differential diagnosis included pilonidal cyst, skin abscess, cellulitis, furuncle, and hidradenitis suppurativa.

Diagnosis. The patient was treated with trimethoprim-sulfamethoxazole to cover for potential methicillin-resistant Staphylococcus aureus and was referred to a pediatric surgeon. The discharge from the dimple was sent for culture and grew mixed skin flora. The pediatric surgeon saw the patient 5 days later, at which time the discharge had improved greatly, and the he was diagnosed with a congenital dermal sinus tract. Ultrasonography scans showed a subcutaneous, 2.9-cm, blind-ended sinus tract with connection to the skin surface in the right lower back/hip.

He underwent surgical resection 6 weeks after initial presentation. The postsurgical pathology report described a sinus tract lined by acanthotic squamous epithelium and granulation tissue. Multiple hair shafts were visualized in the lumen and in the wall, causing a foreign body reaction. The final diagnosis was a pilonidal sinus (Figure 3).

Figure 3. The patient’s pilonidal sinus after surgical removal.

Discussion. Pilonidal sinus disease is a common condition of the skin and subcutaneous tissue. It affects males more often than females and typically presents in the late teens and early 20s. The most common location is the gluteal cleft. Pilonidal sinus disease is more often acquired and less often congenital.¹

It is hypothesized that hair in the gluteal cleft creates a foreign body reaction that ultimately leads to the formation of a pit and may then subsequently develop a secondary infection.² Factors that predispose individuals to developing pilonidal sinus disease include male gender, dark skin, deep gluteal cleft, obesity, young age, local trauma, sedentary lifestyle, and increased hair density in the gluteal cleft.³

There is no typical presentation of pilonidal disease. The presentation varies from being asymptomatic with only a small pit on examination, to an acute infection with pain and purulent drainage, to chronic or recurrent drainage and pain. The diagnosis is usually made clinically based on characteristic findings, including a midline pit in the gluteal cleft, and imaging studies generally are not required. However, in this patient’s case, the location of the pit was not typical, making the diagnosis less clear.

Management varies depending on the presentation. In patients who are asymptomatic, observation often is the only treatment needed, since surgical resection may lead to increased morbidity.⁴ For an acute abscess, prompt incision and drainage is the treatment of choice, and antibiotics are generally only used to treat concomitant cellulitis. Antibiotics alone are not sufficient to successfully cure pilonidal disease.⁵ The recurrence rate for pilonidal abscesses varies from 10% to 55%, with higher rates in lateral sinus tracts or in those with multiple pores.^2,5 Evidence suggests that gluteal cleft shaving may be used to reduce the risk of recurrence.⁵ For chronic or recurrent pilonidal disease, complete surgical excision of the sinus is the treatment of choice.²

Our patient has done well 1 year after complete surgical excision and has had no complications or recurrences.

REFERENCES:

1. Franckowiak JJ, Jackman RJ. The etiology of pilonidal sinus. Dis Colon Rectum. 1962;5:28‐36. doi:10.1007/BF02616408
2. Humphries AE, Duncan JE. Evaluation and management of pilonidal disease. Surg Clin North Am. 2010;90(1):113-124. doi:10.1016/j.suc.2009.09.006
3. Søndenaa K, Andersen E, Nesvik I, Søreide JA. Patient characteristics and symptoms in chronic pilonidal sinus disease. Int J Colorectal Dis. 1995;10(1):39‐42. doi:10.1007/BF00337585
4. Doll D, Friederichs J, Düsel W, Fend F, Petersen S. Surgery for asymptomatic pilonidal sinus disease. Int J Colorectal Dis. 2008;23(9):839‐844. doi:10.1007/s00384-008-0476-2
5. Steele SR, Perry WB, Mills S, Buie WD; Standards Practice Task Force of the American Society of Colon and Rectal Surgeons. Practice parameters for the management of pilonidal disease. Dis Colon Rectum. 2013;56(9):1021‐1027. doi:10.1097/DCR.0b013e31829d2616