Dye laser clears children's birthmarks.

Dye laser clears children's birthmarks 

Researchers report success in using a new form of laser treamtnet to clear up port-wine stains in children. Until now, physicians have had no reliable treatment for children with this distinctive birthmark, which appears as a red or red-purple stain on the skin.

During the past several decades, researchers grappling with the problem have tried grafts and even tattooing techniques to produce normal-looking skin, but to no avail. About 10 years ago, scientists developed an argon-laser therapy for adults with port-wine stain. But the argon laser failed to win wide pediatric use because it produced unacceptable scars in children.

In the Feb. 16 NEW ENGLAND JOURNAL OF MEDICINE, Oon Tian Tan, Karen Sherwood and Barbara Gilchrest of the Boston University Medical Center describe testing a more accurate laser, the dye laser, on 35 patients aged 3 months to 14 years with disfiguring port-wine stains on the head and neck. The researchers found the average patient needed 6.5 laser sessions to clear the stain, but the results were dramatic. "Treated skin was identical in texture and color to adjacent normal skin in 33 of the children," they report. The other two children had small, isolated scars in parts of the skin that had been accidentally traumatized after laser treatment, the researchers note.

The work suggests the dye laser preferentially targets the abnormally large blood vessels underlying the skin that cause port-wine stain. The researchers picked a specific dye that emits energy in a wavelength absorbed by oxyhemoglobin, the red pigment in blood. The laser delivers its heat only to blood vessels, which it destroys, but passes harmlessly through nearby translucent tissue. During the next few weeks, the abnormal blood vessels are replaced by blood vessels of normal size, and skin color gradually fades to a normal tone.

The argon laser may not be as specific as the dye laser, Tan says. She suggests that from an argon laser spreads to damage nearby collagen, causing scar formation. The problem is especially serious in children, whose skin tends to scar more than that of adults.

The treatment may bring relief to parents worried about the birthmark's impact on a child's development. "These children need not be scarred by the psychological impact of these lesions anymore," says Tan, who notes that children with port-wine stain often are shunned by other children.