Hair re-grows after laser removal

Key Points

Cambridge, Mass. - When Ranella Hirsch, M.D., Rox Anderson, M.D. and colleagues from the Wellman Laboratories first presented a case series on hair growth after laser hair removal several years ago, the phenomenon was vastly under-recognized. To this day, it remains poorly understood and under-reported.

However, Dr. Hirsch suggests that dermatologists can learn how to identify at-risk patients to prevent the occurrence of darker, denser hair growth after laser treatment. She also highlights the absolute need to make patients aware, pre-treatment, of the potential for this complication with a complete informed consent process.

"There seems to be some predictability of certain patient subsets more prone to develop this problem," says Dr. Hirsch, a dermatologist in private practice here, and president-elect of the American Society of Cosmetic Dermatology and Aesthetic Surgery.

While the cause of this problem is unclear, it appears to predominate in Fitzpatrick type III or IV patients, mainly women, typically with fine, dark, downy hair most often on the face. Occasionally it can be seen on adjacent skin in women who have been treated at too low a fluence and/or too short a wavelength.

"What seems to happen is that something is triggered that actually causes new hair to grow at or adjacent to the treatment site," Dr. Hirsch tells Dermatology Times.

Successful treatment

While it's unknown exactly why the hair growth occurs in these groups of patients, even the newly grown hair can usually be addressed by aggressive treatment with longer wavelengths and much higher fluences, Dr. Hirsch says.

"Patients must be advised that this will require a significant number of additional treatments," she says, "and the treating dermasurgeon must take great care with the treatment of darker skin types to provide adequate epidermal protection.

Challenges

"The big challenge that we face right now is the overwhelming increase in the number of inexperienced people who are treating more and more complicated cases, combined with lasers being marketed as safe for everyone," Dr. Hirsch says.

The subtleties of laser-skin interactions require a detailed understanding of how different wavelengths are affected by the presence of melanin or a tan, or how certain skin and hair combinations can affect efficacy. Another challenge is the continued under-reporting of these phenomena at non-traditional facilities, Dr. Hirsch says.

"Physicians acknowledge that such challenges can occur and keep records of these things - it's how we learn from complications. But in the medi-spa environment, phenomena like hair growth and other complications after laser treatment remain highly under-reported," she says.

Increasingly, people are often motivated by cost to seek laser treatment in nontraditional environments like shopping malls, and then wind up spending more to repair the damage created with poor care.

"There's nothing more important that we, as dermatologists, can offer our patients than our expertise," Dr. Hirsch says. "It's no bargain to the patient if they're getting someone who doesn't know what they're doing."

For more information:

Hirsch RJ, Farinelli WA, Laughlin SA, et al. Hair removal induced by laser hair removal (abstract) Lasers Surg Med. 2003;32(suppl 15):63.

Alajlian A, Shapiro J, Rivers JK, et al. Paradoxical hypertrichosis after laser epilation. J Amer Acad Dermatol. 2005;53:85-88.

Kontoes P, Vlachos S, Konstantinos M, et al. Hair induction after laser assisted hair removal and its treatment. J Amer Acad Dermatol. 2006;54:64-67.