The temperatures reached and the damage caused to hair follicles by the normal-mode ruby laser when used for depilation

Mechanisms of Laser Hair Removal: Could Persistent Photoepilation Induce Vitiligo or Defects in Wound Repair?

BACKGROUND

Current laser hair removal modalities achieve a long-term but not persistent (irreversible) hair loss.

OBJECTIVE

This review highlights the mechanisms of the current laser hair removal technology and explores possible side effects.

METHODS

The literature is reviewed.

RESULTS

The hair shaft plays a key role in the mechanisms underlying current photoepilation procedures by acting as a vector for heat transfer. Together with inherent properties of the hair growth cycle and the anatomic specifics of the follicular stem cells located in the bulge, the crucial role of the hair shaft and its lack of complete destruction with present technology are also likely culprits for the nonpersistent nature of present laser hair removal. Future persistent photoepilation may be associated with vitiligo or vitiligolike changes. Disturbances in wound repair of previously lasered sites are less likely.

CONCLUSIONS

The currently available laser hair removal protocols are safe, not the least because they achieve long-term but not persistent epilation. The adverse effects of persistent laser hair removal technology possibly available in the future are potentially problematic.

Effect of wax epilation before hair removal with a long-pulsed alexandrite laser: a pilot study

BACKGROUND

Recent reports indicate that laser hair removal is most effective on anagen hairs. However, no published trials have examined laser epilation after hair cycle synchronization.

OBJECTIVE

To evaluate the potential for enhanced laser hair removal after the induction of telogen hairs into anagen by wax epilation.

METHODS

We identified four 2.5-cm square areas with equivalent hair length and density on the backs of 13 dark-haired white men. To induce typically telogen hairs into anagen, two areas on each patient were wax epilated. Two weeks later, one waxed area and one unwaxed area were treated with a long-pulsed alexandrite laser. One month after laser treatment, a subjective comparison was made based on hair density, length, and thickness.

RESULTS

In 12 of 13 patients, lasered areas that had been pretreated with wax epilation were clearer of hair as compared with areas that had been pretreated by shaving (P=0.0034). No significant difference was noted between waxed and unwaxed control areas that had not been laser treated (P=1.0).

CONCLUSION

Wax epilation 2 weeks before laser hair removal improves cosmetic outcomes at 1 month. This effect may be secondary to the recruitment and heightened sensitivity of early anagen hairs.

The long-term results of ruby laser depilation in a consecutive series of 346 patients

The goal of this study was to prospectively assess the long-term results of ruby laser depilation in 346 consecutive patients who underwent hair removal at 402 anatomical sites. The patients were treated using a ruby laser, with mean power ranging from 8.6 J to 15.7 J according to skin type. Results were assessed using two outcome measures-the percentage reduction in hair density and the hair-free interval. The median reduction in hair density was 55 percent (range, 0 to 100 percent) at a median time of 1 year after the last treatment session. The median hair-free interval was 8 weeks. Patients underwent a median number of four treatment sessions. Forty-three of the 346 patients were treated at more than one anatomical site. Of the sites treated, 75 percent reduction in hair density was achieved in 22 percent, 90 percent reduction was achieved in 2.2 percent, and complete depilation was achieved in only 0.7 percent. Darker colored hair was more effectively treated. Treatment efficacy was not affected by anatomical site, with the exception of the faces of male patients, which were found to be particularly resistant to treatment. There was a significant correlation between the number of treatments given and the outcome. The overall complication rate was 9.0 percent (36 of 402 sites) with respect to pigmentary changes and blistering, but varied according to Fitzpatrick skin type. The complication rate was highest in skin types V and VI (24.7 percent), with no complications in skin type I. Although a greater than 50 percent reduction in hair density was achieved in half of the 346 patients treated, complete depilation was achieved in only an extremely limited number of patients.