Side Effects of Laser Treatment of Nevus of Ota

Lasers have revolutionized the treatment of nevus of Ota and other dermal melanocytoses. The Q-switched ruby (694 nm), Q-switched alexandrite (755 nm), and Q-switched Nd:YAG (1064 nm) lasers have all been shown to effectively treat nevus of Ota. As with many new treatments, adverse effects accompany the benefits, and this long-term, large study from a Japanese hospital proves that these treatments are no exception.
More than 400 patients with nevus of Ota were treated over 16 years; 101 of these patients were treated with the Q-switched ruby laser and evaluated 1 year after the last treatment. Long-standing hypopigmentation was the most common side effect, affecting almost 17 percent of patients. Almost 6 percent of patients had hyperpigmentation. One patient whose nevus of Ota had cleared completely developed a recurrence.
Comment: Rates of clearing nevus of Ota with the Q-switched ruby and other short-pulsed lasers approach 100 percent. Although recurrences are very uncommon, side effects -- unfortunately -- are not. Hyperpigmentation was relatively rare and most often temporary, but hypopigmentation was relatively common and permanent in almost 17 percent of patients. Given the similar wavelength and the resulting similarity in melanin-absorption spectra, it is likely that the Q-switched alexandrite laser would produce the same kind of pigmentary side effects as the ruby laser. Q-switched Nd:YAG lasers, however, are less likely to produce such changes, because at 1064 nm, their light is less well absorbed by melanin pigment. Only long-term evaluation of the other Q-switched lasers will determine their actual side-effect profiles, but theoretical analysis leads to the prediction that the Nd:YAG laser will become the laser of choice for this condition.