Cold Air Cooling Increases the Risk of Postinflammatory Hyperpigmentation Following Q-switched Nd:YAG Laser Treatment of Acquired Bilateral Nevus of Ota-like Macules

Wanitphakdeedecha, MD, Woraphong Manuskiatti, MD, Sasima Eimpunth, MD
Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, THAILAND

BACKGROUND:

Postinflammatory hyperpigmentation (PIH) is a common adverse effect following laser treatment in Asian skin. Various attempts to reduce the occurrence of PIH have included sun avoidance, use of pre- and postoperative treatment regimens, and techniques for epidermal protection. Epidermal cooling may reduce the nonspecific thermal injury caused by the laser pulses and consequently minimize the incidence of PIH.

OBJECTIVE:

The aim of this study was to investigate the effect of cold air cooling on the incidence of PIH following laser treatment in Asian subjects.

METHOD:

A total of twenty-one Thai females with acquired bilateral nevus of Ota-like macules (Hori’s nevus) were treated with a 1,064-nm Q-switched Nd:YAG laser at an average fluence of 7.0 J/cm² using a 3-mm spot size. The same laser fluence was used on both sides in individual patients. One randomly selected side of the face on all subjects was cooled with a cold air cooling device 30 seconds before, during, and after laser irradiation, whereas the other side was irradiated without cooling. The occurrence of PIH was objectively evaluated by measuring the melanin index using a SpectroPhotometer, and subjectively assessed by two non-treating physicians before treatment and once weekly for a total period of 4 weeks. Adverse sequelae of the treatment were also evaluated at the same follow-up visit.
Before Treatment
Cooling
Figure 1-1
No Cooling
Figure 2-1
1 week
Figure 3-1
Figure 4-1
2 weeks *
Figure 5-1
Figure 6-1
12 weeks
Figure 7-1
Figure 8-1
Figure 1-8 A 35-year old patient with Hori’s nevus. The left side was treated with cold air cooling and the right side was treated without cooling.
* Note PIH of the lesions on the cooled side (Figure 5)