Capillary Malformation Symptoms & Causes

LIke ThisLIke ThisLIke ThisLIke ThisLIke This

Contact the Vascular Anomalies Center

What are the symptoms of a capillary malformation?

The only sign of a capillary malformation is the birthmark itself: a reddish-pink stain that usually appears on the face or neck, but can show up anywhere in your child’s body. A capillary malformation can darken in color and your child's skin can thicken as she ages, and will grow as your child grows.

Tiny growths called “blebs”, which bleed easily and are sometimes painful, can appear from the malformation. A capillary malformation can also be painful if it’s covering a deeper vascular anomaly.

Rarely, a capillary malformation can be a sign of an underlying abnormality. For instance:
  • A capillary malformation over the spinal column can sometimes be associated with spinal abnormalities.
  • A capillary malformation can cover a deeper vascular abnormality involving your child’s arteries, veins or the lymphatic system, such as Klippel-Trenaunay syndrome.
  • Very rarely, if the stain covers part of the forehead and upper eyelid, your baby should be evaluated for neurological problems, as it could be a sign of a very rare condition called Sturge-Weber syndrome. Only eight percent of kids with a facial capillary malformation have neurological problems.

What causes capillary malformations?

Researchers believe that these malformations occur while your child is still in the womb. For reasons that aren't clear, the capillaries— the smallest blood vessels in the body—expand, allowing a greater-than-normal amount of blood to flow through them, staining the skin.

No known food, medication or activity a mother did during pregnancy can cause her child to have a capillary malformation.

We are grateful to have been ranked #1 on U.S. News & World Report's list of the best children's hospitals in the nation for the third year in a row, an honor we could not have achieved without the patients and families who inspire us to do our very best for them. Thanks to you, Boston Children's is a place where we can write the greatest children's stories ever told.”
- Sandra L. Fenwick, President and CEO

Boston Children's Hospital 300 Longwood Avenue, Boston, MA 02115 617-355-6000 | 800-355-7944

Close