Hyperpigmentation with Laser Procedures - Risks and Treatment
Hyperpigmentation is a the darkening of the skin in or around a treatment site, (in this case a laser-treated site). Increased melanin production by the melanocytes of the skin in response to thermal changes and inflammation. Any kind of laser treatment, whether it is the kind that causes deep injury to the skin, such as a carbon dioxide laser, or a q-switched laser that sends much less energy into the skin, can cause hyperpigmentation. By minimizing thermal damage to the normal skin, one can minimize the risk of hyperpigmenation. It is generally temporary but recovery time can vary widely, lasting a few weeks to months. Hyperpigmentation is not the same as scarring, although both scarring and hyperpigmentation can occur in the same location.
In a review of 3143 laser hair removal procedures on 480 patients, Lanigan showed that darker patients were more likely to be affected by hyperpigmentation. There was a risk of 1% in the lightest skin types vs. 9.9% in the darkest. The type of laser used affects the risk of hyperpigmentation. In another study of 800 laser hair removal procedures, the risk of hyperpigmentation with a long-pulsed diode laser was only .25%. Ruby lasers, on the other hand, are now no longer widely used for laser hair removal due to the higher risks of hyperpigmentation in darker-skinned patients.
Hydroquinone has been a mainstay of treatment for hyperpigmentation. It comes in different topical concentrations (most commonly a 4% prescription-strength). Hydroquinone is a blocker of an enzyme used in chemical reactions to create melanin from the amino acid tyrosine. Hydroquinone is FDA-approved but does carry some precautions. It should not be used chronically (more than 6 months) because it can lead to a different kind of skin darkening, called ochronosis. This is not the same as hyperpigmentation. Following prescribed instructions would keep this from being a problem.
