Quick Check
Not sure if your symptoms match pilonidal disease?
What Pilonidal Disease Looks Like: Visual Symptoms
- A tender lump or swelling
- Redness and soreness in the area
- Drainage of pus, clear fluid (sometimes smelly), or blood
- Small holes along the buttock cleft or to the side
Non-Visual Symptoms
- Pain when sitting or bending
- Fever if the infection is severe
- Deep, throbbing pain with or without a lump
- Lower back pain (sometimes, possibly from sitting in odd positions)
Everyday Questions
How do I know if it’s Pilonidal Disease and not something else?
If the lump is in the upper buttock crease and gets swollen, drains, or is painful to sit on, it’s very likely Pilonidal. Other conditions in this area (like boils or abscesses) are less common. The closer to the anus, the more likely it is that it may be an Anal Abscess, Fistula, or Anal Fissure.
Do I need tests or scans?
In most cases, no. Doctors usually diagnose Pilonidal Disease with a simple physical exam. Imaging (such as ultrasound or MRI) is only used if the sinus is very complex or if there are other concerns. There have been patients with very deep tracts and abscesses, and no obvious lump at the top of the cleft, and those issues were only found with advanced imaging.
X-ray – Not helpful (soft tissue doesn’t show).
Ultrasound – Can spot superficial abscesses.
CT scan – Useful in emergencies, deep abscess suspicion, or when MRI is not available.
MRI (with contrast) – Best test for mapping tracts and complex/recurrent disease.
Does it itch?
It can, especially if you have drainage indicating active infection.
Do kids get pilonidal disease?
It’s rare before puberty. Most cases appear in teenagers and young adults.
Can you get Pilonidal Disease in other places?
Technically, a Pilonidal occurs only in the buttock cleft area. There are similar types of abscesses reported in the umbilicus (navel), breast, pubic region, and armpit… these locations suggest Hidradenitis Suppurativa rather than Pilonidal Disease. There is a similar disease called Barbers’ Pilonidal Sinus, which is caused by hair digging into the soft tissues between the fingers and tends to occur in animal groomers and barbers.
So, what ARE those tiny holes?
The small holes are either large pits or sinus openings. Pits can eventually form sinuses, which are tracts under the skin that connect to the abscess and allow it to drain. Severe Pilonidal Disease can involve multiple tracts; early treatment is important.
What to Expect at the Doctor’s Office
- History: Your doctor will ask about pain, swelling, drainage, and past flare-ups.
- Exam: They’ll look for pits, sinus openings, or swelling in the midline cleft.
- Differential diagnosis: They may rule out boils, perianal fistulas, hidradenitis, or skin infections.
- Tests: Rarely needed unless the presentation is unusual.
Pilonidal Diagnostic Images
Acute Pilonidal abscess, front view
Pilonidal abscess, side view
Preparing for lancing a Pilonidal abscess
Pilonidal Sinus Images
Several sinus openings after a lancing
Series of sinus openings & pits
Pilonidal sinuses, extreme case
For Medical Professionals
- Typical presentation: midline pits in the natal cleft, with or without secondary sinus tracts.
- Exam tip: Always check for pits — they define Pilonidal Disease and distinguish it from Hidradenitis or perianal fistula.
- Imaging: Reserved for recurrent, complex, or atypical disease. MRI can help distinguish pilonidal tracts from fistulous disease.
- Diagnostic pitfalls: Mislabeling congenital sacral dimples in infants as pilonidal (they are not); assuming boils in the lateral buttocks are Pilonidal (often Hidradenitis).
- Pathophysiology: Aligns with the follicular occlusion tetrad (occlusion → rupture → secondary foreign body reaction to hair).
Imaging & Pilonidal Disease
X-Ray
- Not useful. Pilonidal disease involves soft tissue and skin, not bone.
- X-rays cannot visualize pits, sinus tracts, or abscesses.
- Doctors may order an X-ray only if they suspect bone involvement, which is very rare and usually occurs in advanced, neglected cases.
Ultrasound
- Sometimes used.
- Can help identify fluid collections (abscesses) or superficial tracts close to the skin.
- Portable, inexpensive, and quick — but not sensitive for complex or deep disease.
CT Scan
- Rarely used, but can help in selected cases.
- Provides a cross-sectional view of soft tissue, so it can detect larger abscesses or sinus extensions.
- Downsides: radiation exposure, less detail of soft tissue compared to MRI.
- Doctors may use CT scans in emergencies if an MRI is unavailable and they suspect a deep pelvic or retrorectal abscess.
MRI (with contrast)
- Doctors consider MRI with contrast the gold standard for advanced imaging.
- Best at showing complex sinus tracts, deep abscesses, and distinguishing Pilonidal Disease from perianal fistula.
- Particularly helpful for:
- Recurrent or atypical disease
- Suspected tracts extending toward the anus or pelvic structures
- Pre-operative mapping for flap surgery in very complex cases
When Imaging Is Considered
- Doctors do not order imaging for first-time cases with obvious pits and abscesses.
- They may recommend an MRI for patients who experience recurrent episodes, have failed surgeries, or have unusual anatomy.
- If a patient presents with fever, spreading infection, or very deep pain, imaging helps rule out other problems (like fistulas or deep-space abscesses).
Go Here Next:
A Sacral Dimple is not the same as Pilonidal Disease discussed on this website. Here is a quick overview for new parents of a baby with a Sacral Dimple.
How Pilonidal Disease develops in the natal cleft, based on theories and research of Dr. John Bascom. What are the risk factors?
Do you have a Pilonidal?
Check your symptoms here.