What it is
Hyperpigmentation is characterized by increased production or accumulation of melanin.
What causes it
Epidermal and dermal hyperpigmentation can be dependent on either increased numbers of melanocytes, melanocytic dendrites or activity of melanogenic enzymes. Ultraviolet light, chronic inflammation and rubbing of the skin, as well as abnormal α-melanocyte stimulating hormone (α-MSH) release are triggering factors for these disorders.
What it looks like
The clinical description for hyperpigmentation varies pursuant to the type of hyperpigmentation (melasma, postinflammatory hyperpigmentation (PIH), etc.). Generally, hyperpigmentation is characterized by the appearance of lesions that vary in color, ranging from light brown to black. Some, like the port-wine stain, can be reddish to purplish in color.
How to treat it
Traditionally, hyperpigmentation has been treated using depigmenting agents (bleaching compounds) and, more recently, physical therapies such as lasers.
The most common depigmenting agents fall into three categories: those used before melanin synthesis, those used during melanin synthesis and those used after melanin synthesis. Here are the most common products in each of these categories:
Before Melanin Synthesis: C2-ceramide, Tretinoin, Retinoids, Lactic acid, Glycyrrhiza Glabra root extract (licorice root), Undecylenoyl phenylalanine
During Melanin Synthesis: Hydroquinone, Azelaic acid, L-ascorbic acid, Arbutin, Kojic acid, Lactic acid, Phenylethyl resorcinol
After Melanin Synthesis: Linoleic acid, Lactic acid, Glycolic acid, Retinoic acid
Treatments with argon laser, CO2 laser, Nd:YAG laser or Q-switched ruby lasers have been reported. Melanin photothermolysis can be obtained with any laser light having a wavelength in the absorption of melanin and sufficient energy levels to target melanosomes.
Therapies using other chemical agents have also been proposed, such as cryotherapy with liquid nitrogen, laser surgery, chemical peeling and superficial microdermabrasion.
PCA SKIN® product options for treatment include: Pigment Gel ®, Pigment Gel® HQ Free, C-Strength 15% with 5% Vitamin E, Intensive Clarity Treatment: 0.5% pure retinol night, Brightening Therapy with TrueTone and Perfecting Protection SPF 30.
Source: Stefania Briganti, Emanuela Camera, and Mauro Picardo. Chemical and Instrumental Approaches to Treat Hyperpigmentation. Pigment Cell Research, Volume 16, Issue 2, pages 101–110, April 2003.