Hyperpigmentation is a catch-all term for a variety of skin pigment disorders, all of which involve extra melanin — hence the prefix hyper, meaning excessive. But that’s where many of the similarities end: when it comes to causes, triggers, and appearance, the range of pigment abnormalities is varied and complex.

From the factors that contribute to its onset, to some of the latest promising treatments, we’re taking a closer look at how hyperpigmentation happens.



What is hyperpigmentation?

Simply put, hyperpigmentation is an area of skin that’s darker than a person’s inborn, overall skin color. Although research is ongoing, hyperpigmentation seems to involve not only the production of more melanin by the melanocytes, but also an increased number (and/or altered distribution pattern) of melanosomes (the “packets” where melanin protein accumulates).

The formation of melanin is extremely complex — which means there are many different opportunities for things to go awry. A person’s level of melanin is classified in two ways:

• Constitutive pigmentation: aka our natural skin color, determined by genetics
• Facultative pigmentation: additional color resulting from environmental factors

Many of us are familiar with some of the normal variations in constitutive pigmentation: birthmarks, darker skin around the eyes, and deeper color on the palms and soles of the feet, for example. But it’s the second category — facultative pigmentation — that we typically think of as hyperpigmentation. Causes and triggers include:

• Underlying disorders (relatively rare): Carney complex, Addison’s disease, Schamberg's disease
• Hormonal changes: pregnancy, birth control pills, certain medications
• Sun exposure: lentigines, ephelides (freckles)
• Inflammation: acne, injury

How is hyperpigmentation diagnosed?

There are essentially two ways a dermatologist can diagnose a pigment disorder:

• By histology: examining the lesion with magnification
• By Wood’s light: an ultraviolet lamp that illuminates areas of concern

These tools help dermatologists classify the pigmentation into one of three types:

• Epidermal melanosis: typically dark brown, with sharply delineated borders under Wood’s lamp, consisting of excess melanin in the epidermis with a normal number of melanocytes
• Dermal melanosis: typically brown/gray, absent of sharp demarcations under Wood’s lamp, consisting of excess melanin in the dermis
• Mixed hypermelanosis: a combination of the previous types shown under Wood’s lamp, with increased melanin in both the epidermis and the dermis

What are the most common types of hyperpigmentation?

According to Dr. Sandra Lee (aka Dr. Pimple Popper), there are a few types of hyperpigmentation that patients tend to be concerned about. Here’s an overview.

Solar lentigines

Also known as sun spots or liver spots, these dark patches are caused by the accumulation of UV damage over time — hence why they’re also called age spots. They’re distinguished by an increased number of melanocytes (the specialized skin cells that make melanin), not just an increase in pigment.

Treatment for sun spots will vary depending on severity and Fitzpatrick skin type, but may include:

• Cryotherapy — freezing with liquid nitrogen
• Lasers — highly concentrated, single-wavelength, may not be suitable for darker skin types
• IPL — intense pulsed light, broader-spectrum than lasers
• Chemical peel — commonly TCA or glycolic acid
• Retinoids — encourage shedding of pigmented cells, inhibit tyrosinase
• Sunscreen — protects against radiation that triggers melanin production

Melasma

Sometimes called chloasma or “mask of pregnancy,” this hormonal-driven type of hyperpigmentation is challenging to treat. It typically presents in a symmetrical pattern on the forehead, cheeks and sometimes the upper lip and around the mouth. Research suggests that changes in both the epidermis and the dermis may be involved in the development of melasma.

Melasma that is closer to the surface (aka epidermal) typically responds to treatment more readily than deeper (dermal) melasma. Many methods that work well for reducing other forms of hyperpigmentation (like lasers, IPL, or deep peels) can actually make melasma worse — so it’s crucial to talk to your dermatologist first. Generally speaking, topical skincare and mild peels are the norm:

• Chemical peel — superficial only, glycolic acid preferred
• Retinoids
• Kojic Acid
• Sunscreen

Post-inflammatory hyperpigmentation

PIH is the result of trauma to the skin: either from some kind of injury like a cut or burn, or from a skin condition like acne. As the skin heals, excess melanin is deposited. Often, post-inflammatory hyperpigmentation disappears on its own over time. It’s typically treated with topical solutions, like:

• Alpha hydroxy acids
• Retinoids
• Kojic Acid
• Sunscreen

When acne is the cause of PIH, treating the pimples with salicylic acid (and not popping/picking/squeezing!) can help reduce the likelihood of forming dark marks in the first place.

What’s the best skincare to treat hyperpigmentation?

While we’ve reviewed some of the most common dermatological options for reducing pigmentation, recent research shows promising results for additional over-the-counter skincare ingredients. Here’s a roundup of both traditional and emerging topical OTC hyperpigmentation treatments and their means of action:

• Exfoliants: increase the turnover of pigmented epidermal cells with glycolic acid, salicylic acid and lactic acid. Try it: SLMD AHA/BHA Swipes.
• Retinoids: inhibit melanosome transfer and tyrosinase activity. Try it: Retinol Resurfacing Serum
• Corticosteroids: reduce inflammation and melanocyte activity.
• Kojic Acid: antioxidant properties help minimize appearance of environmental damage. Try it: Dark Spot Fix.
• Niacinamide: inhibits melanosome transfer into keratinocytes. Try it: All Bright Niacinamide Brightening Toner.
• Azaleic acid: inhibits tyrosinase and DNA in abnormal melanocytes
• Vitamin C: inhibits tyrosinase and boosts skin’s antioxidant capacity. Try it: Vitamin C Serum.
• Tranexamic acid: reduces melanocyte-stimulating hormone (MSH) and may decrease blood supply to melanocytes.
• Broad-spectrum sunscreen: reduces exposure to UV radiation. Try: SLMD Dual Defender SPF 30.