A common cause of recurrent abscesses in the natal cleft of young men.
The condition is acquired, and it is possible to reduce its risk factors.
In an acute phase, the abscess is incised and drained.
Surgical intervention is often needed in chronic cases.
Definition, risk factors and symptoms
Pilonidal sinus is an acquired condition affecting the natal cleft area (the cleavage between the buttocks) where hairs have become trapped in the subcutaneous tissue and form a cavity.
The subcutaneous cavity easily becomes infected and a painful abscess may develop.
Risk factors include obesity, hairy natal cleft and an occupation requiring prolonged sitting.
Pilonidal sinus is most common in men aged between 15 and 30 years.
In an acute phase, the abscess is incised under local anaesthesia laterally to the natal cleft (for example, a scalpel blade no. 11). The skin overlying the cavity is infiltrated with local anaesthetic.
The debridement of inflamed granulation tissue, necrotic tissue and any hair present is carried out using an appropriate instrument and the cavity is then rinsed with, for example, normal saline. The incision wound is left open, and the tissue growth closing the wound starts at the bottom of the cavity.
A ribbon gauze dressing (e.g. Sorbact® ) may be left in the cavity to absorb the bacterial mass. The wound is showered or irrigated morning and evening for a few days.
Systemic antimicrobials are generally only indicated if cellulitis of the surrounding tissue is suspected.
The antimicrobials and treatment period are the same as used in the management of an abscess Skin Abscess and Folliculitis: for example, cephalexin 500-750 mg three times daily or flucloxacillin 750-1000 mg three times daily for 7-10 days.
The treatment of pilonidal sinus should not consist solely of systemic antimicrobials.
After the procedure, it is important to pay attention to meticulous hygiene in order to keep hair and other contaminants from entering the wound.
Prevention of recurrence
Abscess recurrence is common.
The best preventative methods against recurrence are good local hygiene, reduction of time spent sitting down and weight loss.
Any pressure exerted on the natal cleft should be minimised by employing ergonomic planning procedures at the workplace.
Hair and debris should be removed when washing.
Hair removal (shaving, chemical or laser depilation) has been shown to prevent recurrences.
Specialist consultation
A surgical opinion should be sought in complicated and recurring cases; several surgical techniques are in use.
Asymptomatic sinuses should not be surgically removed.
References
Halleran DR, Onwuka AJ, Lawrence AE ym. Laser Hair Depilation in the Treatment of Pilonidal Disease: A Systematic Review. Surg Infect (Larchmt) 2018;19(6):566-572. [PubMed]
Milone M, Velotti N, Manigrasso M ym. Long-term follow-up for pilonidal sinus surgery: A review of literature with metanalysis. Surgeon 2018;16(5):315-320. [PubMed]
Guner A, Cekic AB, Boz A ym. A proposed staging system for chronic symptomatic pilonidal sinus disease and results in patients treated with stage-based approach. BMC Surg 2016;16():18. [PubMed]