Permanent Hair Removal in a Single Treatment? That's a Myth

PARIS — Technological advances in lasers and flashlamp devices have given rise to several hair removal myths, including the belief that permanent hair removal requires only a single treatment, that it can be performed on all hair colors and skin types, and that it is without side effects, Christine Dierickx, M.D., said at the Fourth International Academy of Cosmetic Dermatology World Congress.

Each laser treatment will temporarily remove all the hair and permanently remove about 20%. A hair-free period of about 1–3 months follows most laser treatments, which is then followed by partial regrowth of about 80% of the hairs.

The percentage of new hairs decreases with each laser treatment because additional permanent hair loss with each laser treatment is about 20%, she said.

Patients typically need five treatments, and they should be warned not to pluck or wax their hair because photothermal energy is absorbed by melanin in the hair shaft.

"Without the target, there is no effect," said Dr. Dierickx, director of the Skin and Laser Center, Brussels.

She was unsuccessful in her attempt to create a target by dying white hair, and has had mixed results with the use of radio frequency energy.

Because melanin in the epidermis presents a competing site for energy absorption, hair removal in patients with Fitzpatrick skin types IV-VI is challenging. Such patients can be safely treated with longer wavelength lasers such as an 800-nm diode or 1,067-nm long-pulsed YAG laser.

However, tanned skin is "merciless," and hair removal should typically be delayed 10–12 weeks after tanning, according to Dr. Dierickx.

Photopneumatic therapy or PPx (Aesthera Corp.) is a new treatment modality that combines light-based hair removal and vacuum suction to lift the skin.

The technology manipulates the optical characteristics of the skin, potentially allowing four to five times more energy to be transmitted to the follicles, Dr. Dierickx said.

Preliminary 3-month results were comparable with conventional 800-nm and 1,064-nm lasers, with 5 of 19 patients achieving 90% hair clearance.

No hair removal system is without risks. Recent reports (J. Am. Acad. Dermatol. 2004;51:774–7) and personal experiences show that livedo reticularis is a new possible side effect of laser-assisted hair removal, she said.