MedWire News: Laser hair removal occasionally causes a severe itchy red rash, Spanish skin experts have found.
They say that the skin rash is a "hypersensitivity" reaction that is most likely to affect people who already suffer from allergies such as hayfever or asthma.
To prevent the reaction, allergic patients should have a patch test 24-48 hours before undergoing full laser hair removal, recommend Dr Nerea Landa (Dermitek Clinic, Bilbao, Basque Country) and fellow researchers.
Laser hair removal (epilation) is the most popular laser skin procedure performed worldwide. Common side effects are changes to the skin pigmentation and - paradoxically - stimulation of hair growth.
However, a less common reaction is the development of a severe, itchy rash, known as "urticaria" or "hives," which Dr Landa's team investigated in this study.
The researchers searched a database that contained details of all people who underwent laser hair removal at Spanish beauty clinics over a 4-year period. Of a total of 13,284 people, 36 developed hives within 6-24 hours of the procedure.
The rashes always affected areas of skin treated with the laser, which included the legs, groin, armpit, forearms, and upper lip. Rashes were typically red or purple in colour, often developed in a circular pattern, and had multiple raised itchy spots or patches.
People who developed the reaction were generally given corticosteroid tablets to treat the itching and in all cases the hives disappeared within 7 to 30 days.
Seven people decided not to continue with their planned course of laser hair removal because of the bad reaction. The other patients continued treatment but took corticosteroid tablets for 3 days before each procedure, which was generally effective in preventing further rashes and itching.
In people who developed rashes on several occasions, they typically became less severe over time, the researchers remark.
Writing in Lasers in Surgery and Medicine, Dr Landa and team recommend that people with known allergies (such as eczema, asthma, or hayfever) should have a skin-patch test before undergoing a course of laser hair removal.
They also suggest that people who develop this reaction should be treated with the steroid prednisone in order to reduce the redness and itching.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Joanna Lyford