Changes in pigmentation can occur after any method of skin resurfacing. The changes are due to several effects including removal of pigment cells and change in pigment cell metabolism.
The pigment can increase (hyperpigmentation), decrease (hypopigmentation) or become blotchy. It may leave a line of demarcation between the treated and untreated areas.
Patients who already have a large amount of pigment in the skin are more likely to experience changes than those who do not. The best candidates for resurfacing procedures are light complected patients such as redheads.
If hyperpigmentation begins to develop after surgery early treatment with bleaching agents may help. Some surgeons recommend bleaching agents in all patients and before surgery.
Pigment change seems more likely after phenol peels than TCA (trichloroacetic acid) peels because of a change in metabolism of melanocytes.