What is Pilonidal Sinus?

A pilonidal sinus is a small tunnel or cavity usually forming at the top of the crease between the buttocks. It contains hair and debris and can become infected, causing pain, swelling and redness in the affected area, as well as drainage of pus or blood. 

What is Fistula?

An anal fistula is a tunnel or passageway forming inside an infected gland of the anus and it extends to the opening around the anus. It can be a result of an injury or surgery and cause pain and inflammation around the anus. 

The differentiation is important because pilonidal cyst may mimic Anorectal fistula. Also to know is that pilonidal cyst can evolve into fistula if not treated by a surgeon early.

Dr. M.G. Kartheeka, MBBS, MD(Pediatrics)

Differences Between Pilonidal Sinus and Fistula

1. Causes

Pilonidal Sinus

Conditions that can cause a pilonidal sinus include:

• Any underlying skin problem
• Pressure or friction between the buttocks
• Ingrown hair around the buttock area
• Sitting for long periods

Fistula

Fistulas may develop due to:

• An infection in the anal gland
• Trauma
• Radiation therapy or treatment of anal cancer

2. Symptoms

Pilonidal Sinus

The signs of a pilonidal sinus infection include:

• Pain while sitting or standing
• Swelling of the cyst
• Redness in the affected area
• Drainage of pus or blood from the abscess, causing a foul odor
• Hair protruding from the lesion
• Formation of more than one sinus tract or cleft in the skin
• Low-grade fever

Fistula

Symptoms of a fistula may include:

• A small opening around the anus
• Redness and inflammation around the tunnel
• Blood and pus discharge from the anal opening
• Pain in the rectum and anus region while passing stools
• Fever

3. Diagnosis

Pilonidal Sinus

• A physical examination where the doctor will check the crease of your buttock area, with the cyst often visible to the naked eye.
• Imaging tests may rarely be required, such as a CT or MRI scan, to look for any sinus cavities forming under the surface of your skin.

Fistula

• Imaging tests like MRI provide detailed images of the sphincter muscle and other structures of the pelvic floor.
• Endoscopic ultrasound to identify the fistula, sphincter muscles, and surrounding tissues.
• Fistulography, an X-ray of the fistula, to check the anal fistula tunnel.
• Other tests include a fistula probe, anoscope, flexible sigmoidoscopy, or colonoscopy.

4. Treatment Options

Pilonidal Sinus

• Antibiotics to treat skin inflammation.
• Drainage of pus by opening and cleaning the abscess, followed by sterile dressing to promote healing.
• Laser therapy to remove hair from the area.
• Surgery may be recommended for a recurring pilonidal sinus. The surgeon opens the lesions, removes pus and debris, and then stitches the wounds closed.

Fistula

• Medicines for local application.
• Fibrin glue and collagen plug to seal the tunnel after cleaning.
• Seton placement into the fistula to drain the infection and contents inside the tunnel.
• Fistulotomy involves cutting the infected tunnel, cleaning it, and stitching it in place.
• Endorectal advancement flap uses a flap from the rectal wall to cover the fistula.
• LIFT (Ligation of Intersphincteric Fistula Tract) is a two-stage treatment in which the fistula tunnel is opened, infected tissues are removed, and the fistula is tied off.

5. Prevalence

Pilonidal Sinus

Pilonidal sinuses are common in young adults. They develop more commonly in men than in women because men tend to have more body hair.

Fistula

Anal fistulas commonly develop in adults around the age of 40. They affect males more often than females.

6. Complications

Pilonidal Sinus

• Chronic pilonidal disease
• Retained hair and infected residue, which may make it difficult to locate the sinus pits
• Systemic infection (when an infection spreads throughout your body) which can become life-threatening
• Cancer (specifically squamous cell carcinoma or SCC)

Fistula

• Recurring fistula or abscess
• Increase in the length and number of tracts
• Inability to control bowel movements (fecal incontinence)
• Sepsis or infection that spreads throughout the body
• Peritonitis: an intestinal fistula may cause inflammation and infection of the peritoneum (the membrane lining the abdominal cavity)
• Risk of developing cancer in the fistula tract if left untreated for a long period of time

Pilonidal sinus are very common and the treatment for the same is usually surgical especially when there is an associated discharge, pain and abscess.

Dr. Ashish Bajaj, M.B.B.S., M.D. in Clinical Pharmacology and Toxicology

Conclusion

Understanding the difference between pilonidal sinus and fistula will help you seek the best treatment for the conditions. You must look out for the symptoms of both conditions and visit the doctor as soon as you experience pain and discomfort. It is possible for a person to confuse the two conditions as they have a few similar symptoms, which is why you need immediate medical attention. When you leave the conditions untreated for a long time, it may cause various other complications. Never self-medicate, proper diagnosis of your condition is very important, followed by appropriate treatment and surgery if recommended by the doctor.

Disclaimer: The information provided here is for educational/awareness purposes only and is not intended to be a substitute for medical treatment by a healthcare professional and should not be relied upon to diagnose or treat any medical condition. The reader should consult a registered medical practitioner to determine the appropriateness of the information and before consuming any medication. PharmEasy does not provide any guarantee or warranty (express or implied) regarding the accuracy, adequacy, completeness, legality, reliability or usefulness of the information; and disclaims any liability arising thereof.

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