Sudden growth of hemangioma

[hendest]

My son is three and 1/2.  He has had a hemangioma since birth.  It grew until he turned two and then began to shrink.  It was completely flat until today when it started to swell.  It grew back to it's biggest size in a matter of hours and I'm worried something may be wrong.  Should I be worried.  I found one site online that said that isn't normal and to call a dermatologist.  What would cause this to happen?

[Dr_Aparna]

Hi,
Infantile hemangiomas has a fairly predictable pattern of growth. Most appear during the first weeks of life and grow rapidly (called the proliferative phase) for 6 to 12 months. Then they begin a much slower process of shrinking, or regressing (called the involuting phase), which may take from one to about seven years. Finally, the tumor enters its final, shrunken state (called the involuted phase), after which it will never regrow. Tumor regression is complete in 50% of children by age 5 and in 70% of children by age 7.
Sudden growth of a hemangioma is considered a complication and needs to be treated immediately.Occasionally, a hemangioma that grows or shrinks especially quickly forms an open sore.
This can lead to pain, bleeding, scarring or infection.Corticosteroids can be injected, given by mouth or applied to the skin as treatment.
ref:http://www.mayoclinic.com/health/hemangioma/DS00848/DSECTION=treatments%2Dand%2Ddrugs