Simple Dimples

Dr. Greene’s take on dimples…

Many healthy babies have small dimples on their lower backs. A mother who had just graduated from nursing school came to my office hours chat this week at Her baby had a sacral dimple like this. Her pediatrician told her not to worry about it and ordered an ultrasound in two weeks. Of course she worried – especially after a quick online search of sacral dimples raised questions of spina bifida and neurologic problems. So, at her request, I’m making what we chatted about available for others who are concerned about this — the simple dimple plan for parents.

The first thing that parents need to know is that sacral dimples and related findings are common: about 1 in 20 babies. And most babies with a midline sacral dimple are healthy. Occasionally, these can be a sign of a spinal problem underneath. Sometimes, they are not even true dimples at all, but narrow open tubes that connect to an internal structure such as the intestines or the spinal canal. How do you tell the difference between dimples to smile about, and those to look into further?

There are four simple things to consider:

Is the dimple

  1. deep (the bottom can’t be seen)
  2. large (>0.5 cm in diameter)
  3. high on the back (> 2.5 cm above the anus) or
  4. associated with other skin findings at the site of the dimple (a tuft of hair, a tail, or a Hemangioma)?

If the answer to any of these is yes, then a closer look, such as an ultrasound, may be in order to see what is underneath. Even so, in one study of babies who met at least one of these criteria, most of the dimples (60 percent) turned out to be normal findings in healthy kids. Most of the them that did turn out to be problematic were both high on the back and also associated with other skin findings.

Simple dimples that don’t meet any of the above criteria turned out to be normal findings in 100 percent of the babies studied. In otherwise healthy babies, no ultrasound or other workup is recommended for simple dimples.

Drolet BA – Cutaneous signs of neural tube dysraphism. Pediatr Clin North Am – 01-AUG-2000; 47(4): 813-23 Higgins JC – Simple dimple rule for sacral dimples. Am Fam Physician – 15-JUN-2002; 65(12): 2435 Kriss VM – Occult spinal dysraphism in neonates: assessment of high-risk cutaneous stigmata on sonography. AJR Am J Roentgenol – 01-DEC-1998; 171(6): 1687-92

Published on: July 26, 2005
About the Author
Photo of Alan Greene MD
Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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