Seeing a small dimple at the base of their baby’s spine can worry parents. Online searches for “pilonidal” sometimes add to the confusion. But sacral dimples in newborns are not the same as pilonidal disease. This page explains the difference.
What Is a Sacral Dimple?
- A sacral dimple is a small indentation in the skin just above a baby’s buttocks.
- They are very common, found in about 2–4% of healthy newborns.
- Most sacral dimples are harmless and do not require treatment
Why They’re Not Pilonidal Disease
- Pilonidal disease is acquired, not something babies are born with. It occurs later in life (usually in teens or young adults) when midline pits rupture, allowing hairs and skin debris to penetrate the skin, leading to inflammation and infection.
- A sacral dimple at birth is not the same thing as a pilonidal cyst or sinus.
When Do Sacral Dimples Need More Attention?
Most sacral dimples are “simple” and harmless. However, some may be a marker of an underlying spinal issue, such as spina bifida occulta or tethered cord syndrome.
Doctors may recommend an ultrasound or MRI if:
- The dimple is very deep or large
- It’s located higher up on the back, away from the crease
- There is a tuft of hair, a skin tag, discoloration, or drainage around it
- The baby shows any signs of weakness, abnormal leg movement, or bladder/bowel issues
Key Differences: Sacral Dimple vs. Pilonidal Disease
| Feature | Sacral Dimple (Newborns) | Pilonidal Disease (Teens/Adults) |
|---|---|---|
| When it appears | Present at birth | Usually ages 15–30 |
| Cause | Congenital skin variation; most are harmless | Acquired — hair, friction, and pressure push debris under the skin |
| Common signs | Small skin indentation near the buttocks; usually no symptoms | Painful lump, swelling, redness, drainage of pus or blood |
| Serious concerns | Rarely linked to spinal issues (spina bifida occulta, tethered cord) | Recurrent abscesses, chronic infection, need for procedures or surgery |
| Contagious? | No | No |
| Treatment | Usually none; ultrasound or MRI if atypical (deep, high, hairy, draining) | Self-care, drainage of abscess, or surgery, depending on severity |
| Prognosis | Nearly always benign | Chronic, but treatable with proper care |
What Parents Should Do
Watch for discharge, swelling, or redness around the dimple — these are rare but should be evaluated.
- Most sacral dimples are normal. Mention it at your baby’s check-up for reassurance.
- Ask your pediatrician whether imaging is needed (it is often unnecessary unless other signs are present).
References
Go Here Next:
Now that you know what a Pilonidal is, you’re probably wondering if that’s what is causing your tailbone pain. Start here, then see a doctor to be sure.
How Pilonidal abscesses develop in the natal cleft, based on the theories and research of Dr. John Bascom. What are the risk factors?
Do you have a Pilonidal?
Check your symptoms here.