CHICAGO — A recent multivariate analysis found that low birth weight is the single most significant risk factor for having a hemangioma of infancy.
These findings come at a time when the rates of preterm and low-birth-weight infants continue to rise in the United States, mainly because of assisted reproductive technologies, Dr. Ilona J. Frieden said at the American Academy of Dermatology's Academy 2008 meeting.
In 2005, 8.2% of infants born in the United States weighed 2,500 g or less—the highest percentage since 1968. Physicians can expect to see more hemangioma patients, and should use anatomic location and growth patterns to assess risk and management options, she said.
If one assumes a 15% incidence in preterm infants, 50,000 infants in 2005 in the United States would have one or more infantile hemangiomas, compared with 20,000 in 1985, said Dr. Frieden, director of pediatric dermatology at the University of California, San Francisco.
The new findings are based on research by the Hemangioma Investigator Group (HIG) that compared 420 infants with hemangiomas with 353 patients without hemangiomas seen for other skin problems. With use of multivariate logistic regression analysis, low birth weight was identified as the single most significant risk factor for having a hemangioma.
For each 500-g decrease in weight from a control group of 3,000-g to 3,500-g infants, there was a 29% increase in risk, Dr. Frieden said.
The current study whittles down a list of significant risk factors identified by an earlier HIG study that included female gender; white, non-Hispanic race; prematurity; low birth weight; multiple gestation; and advanced maternal age (J. Pediatr. 2007;150:291–4).
Dr. Frieden said traditional descriptions of infantile hemangiomas as superficial, deep, or mixed fail to capture essential differences in these benign tumors, and that a better classification schema is needed.
Most hemangiomas of infancy can be classified as “segmental” or “localized,” she postulated. Segmental hemangiomas cover a broad anatomic region or recognized developmental unit such as the entire ear, while localized hemangiomas are confined spatially and often appear to arise from a central focal point.
Prior research has shown that segmental lesions are larger, require more intensive and prolonged therapy, and are more frequently associated with developmental abnormalities, complications, and a poorer overall outcome (Arch. Dermatol. 2002;138:1567–76).
More recent data from the HIG, an international consortium of researchers, confirmed these findings. Infants with segmental hemangiomas were found to be 11 times more likely to experience complications and 8 times more likely to receive treatment than were those with localized hemangiomas (Pediatrics 2006;118:882–7). The effect persists, even when controlled for size, Dr. Frieden said.
In addition to distribution, hemangiomas have distinct growth patterns, suggesting a critical period of intervention in the first few weeks to months of life. HIG findings to be published in an upcoming issue of Pediatrics indicate that hemangiomas reach 80% of their maximum size at a mean age of 3 months. By 5 months of age, 80% of hemangiomas have completed their growth, she said. Segmental hemangiomas were found to present 1 month earlier, yet were 10 times larger than were localized hemangiomas.
Intervention, when necessary, is best during this early period because treatments such as systemic corticosteroids work better at preventing growth than shrinking established lesions, Dr. Frieden said.
She proceeded to highlight a pilot study in France that showed rapid improvement with the use of propranolol in nine infants with severe infantile hemangiomas (N. Engl. J. Med. 2008;358:2649–51).
Dr. Frieden characterized the findings as very exciting, but cautioned that the drug's use in infants is off label and that there is no consensus on how to monitor for side effects in very young children. Potential side effects include hypoglycemia, bradycardia, hypotension, and exacerbation of asthma, she noted.
Dr. Frieden said in an interview that she has started two children with complicated segmental hemangiomas on propranolol, but after just 4 weeks, it is too early to say if it is helping.
Dr. Frieden is a consultant for Pierre-Fabre Dermo-Cosmétique and is planning drug studies with propranolol.