Several cases of lingering, web-like skin redness after laser hair removal point to a previously unrecognized side effect of the procedure, according to researchers.

Reporting in the Journal of the American Academy of Dermatology, they describe 10 people in London and Israel who developed “reticulate erythema” after having one or more laser hair removal treatments.

Reticulate erythema refers to inflammation and reddening of the skin in a net-like pattern that arises from the widening of small blood vessels near the skin’s surface. The patients had had the condition for three to 14 months, with no sign of improvement, according to the report’s authors.

Temporary redness and swelling, as well as long-term skin discoloration and scarring, are known to be potential side effects of laser hair removal.

This is the first time reticulate erythema has been linked to the procedure, said the report’s lead author, Dr. Moshe Lapidoth of Rabin Medical Center in Petah Tikva, Israel.

“This is a unique, sometimes irreversible rash,” he told Reuters Health, noting that while some of the 10 patients in his team’s report have improved at this point, none has yet recovered totally.

All of the patients had hair removed with a type of laser known as a diode laser. The laser energy, according to Lapidoth, apparently damaged some blood vessels in the treated area, causing nearby tiny vessels called venules to compensate for the damage by dilating.

“That causes the typical net-like rash,” the researcher said.

It also appears that the side effect may occur mostly in people with a history of chilblains - itchy, red or purple bumps that develop on the skin in response to cold temperatures. Six out of the 10 patients described in the report said they had chilblains in the past.

Patients should immediately stop laser hair removal treatments at the first signs of reticulate erythema, Lapidoth and his colleagues advise. However, they also point out that early signs of the rash could be “easily overlooked,” especially if non-medical staff perform the procedure.

SOURCE: Journal of the American Academy of Dermatology, November 2004.