A case of mottled hypopigmentation after low-fluence 1,064-nm Q-switched neodymium-doped yttrium aluminum garnet laser therapy

Abstract

Melasma is a very difficult pigmented disease to treat with high recurrence rate. Using low-fluence 1,064-nm Q-switched neodymium-doped yttrium aluminum garnet (QSNY) lasers repeatedly for the treatment of melasma is now a common practice in East Asia. However, one of the significant side effects is mottled hypopigmentation that appears as scattered white macules in the middle of melasma lesion. The pathophysiology of these hypopigmentation is yet unknown. The biopsy of the hypopigmented lesion showed decreased melanosome with intact melanocytes, and topical tretinoin may be the effective solution for these types of condition.

Laser toning in melasma

“…A study by Ryu and Kim[53] described a case of toning-induced hypopigmentation that had decreased number of functional melanocytes on histology but normal melanocyte number. [53] Similar finding was also reported by Wong et al [54] in one Chinese patient who has received 40–50 sessions over a 6-month period.…”

Changes in Melanin and Melanocytes in Mottled Hypopigmentation after Low-Fluence 1,064-nm Q-Switched Nd:YAG Laser Treatment for Melasma

“…However, in that study, lesional skin was not compared with adjacent perilesional normal skin. The other studies suggest the number of melanocytes in hypopigmented skin is normal 6 , 7 . In the present study, there was no difference in the mean numbers of MITF-stained melanocytes between lesional skin and perilesional normal skin.…”

Hypopigmentation Induced by Frequent Low-Fluence, Large-Spot-Size QS Nd:YAG Laser Treatments

“…With the increasing demand for laser toning procedures, patients undergoing multiple sessions of laser treatment should be aware of the potential complications. A significant complication that has been increasingly reported in recent literature is guttate hypopigmentation and depigmentation after laser toning with QS 1064-nm Nd:YAG 4 5 . We present three cases of laser-induced hypopigmentation after laser toning that were referred to our tertiary dermatology referral center for treatment.…”