Comprehensive Guide to Melanin & Dark Spots

Melanin is the culprit behind the dark spots that give us an uneven complexion. It is a brown pigment found in the basal layer of the epidermis.

This pigment is synthesised by melanocytes. The process of melanin synthesis is termed melanogenesis. Melanocytes go through different stages of maturation, becoming more pigmented at each stage.

Certain stimulants trigger a gene to produce more of tyrosinase, a copper-containing enzyme that converts tyrosine into melanin. Stimulants that activate the melanocyte include hormones, inflammation (such as acne) and external environmental conditions (ultraviolet light that causes the production of free radicals).

One simple way to reduce melanin production is to use broad-spectrum sunscreens with zinc oxide, titanium dioxide or iron oxide. These substances help block UVA and UVB light, thus impeding the stimulation of melanocytes.

Pigmentary disorders from melanin

Common hyperpigmentation disorders that involve the darkening of an area of skin due to increased melanin include melasma, lentigo, and post-inflammatory hyperpigmentation.

Melasma is usually caused by chronic exposure to ultraviolet radiation or a spike in hormones due to pregnancy or the use of oral contraception. It can be found at the epidermis, dermal layer or mixed, depending on the location of the pigment.

A lentigo is a light or dark brown area of discoloration that can range from 1mm to 1cm across, and is caused by an increased number of melanocytes. Its outline is usually discrete, but can also be irregular. Simple lentigines arise mostly during childhood on areas not exposed to the sun. Solar (or senile) lentigines are found on the backs of hands or on the face, most commonly after middle age.

Post-inflammatory hyperpigmentation (PIH) is the skin’s response to inflammatory skin disorders. Common causes are acne and atopic dermatitis. PIH is caused by the overproduction of melanin caused by skin inflammation.

Treating hyperpigmentation from melanin

Hydroquinone: For 50 years, hydroquinone has been the gold standard treatment for hyperpigmentation. This compound inhibits tyrosinase activity, thus limiting the amount of melanin to be produced. It also alters melanosome formation, possibly degrading melanocytes.

However, prolonged use of topical hydroquinone has shown to have side effects such as ochronosis and permanent depigmentation. Ochronosis is a disorder with blue-black discoloration. As such, hydroquinone is banned in cosmetic formulations and only available through a prescription that should be carefully managed by an accredited dermatologist.

Retinoids are forms of vitamin A that can treat acne, photodamage and PIH. They have various pathways that lead to skin lightening effects, such as accelerating epidermal turnover, reducing pigment transfer and slowing the production of tyrosinase.

With common side effects being erythema, skin irritation, dryness and scaling, it is recommended to use a retinoid only under the supervision of an accredited dermatologist. Corticosteroids (steroid hormones) have anti-inflammatory abilities and are often prescribed along with retinoids to prevent excess irritation.

Arbutin is a botanically derived compound found in cranberries, blueberries, wheat and pears. Though arbutin is a derivative of hydroquinoine, it has shown to be a more controlled way of inhibiting the synthesis of melanin as it does not permanently destroy melanocytes.

Kojic acid is a naturally occurring fungal substance. Its skin-lightening ability works by inhibiting the activity of tyrosinase. However, frequent use can cause side effects of contact dermatitis or erythema (redness of the skin).

Azelaic acid is known to be effective for treating PIH and acne. Azelaic acid depigments the skin in several ways. It can inhibit tyrosinase or reduce levels of abnormal melanocytes. This means that azelaic acid does not influence normal skin pigmentation but only acts on the proliferation of unwanted melanocyte activity.  Side effects are mild and only last for a short period of time. Irritation, burning sensation or mild erythema may emerge, taking 2 to 4 weeks to subside.

Niacinamide is a derivative of vitamin B3. It works by decreasing the transfer of melanosome to keratinocytes. Niacinamide is a stable ingredient as it is unaffected by light, moisture or acids. This ingredient is often incorporated into cosmeceuticals due to its safety profile.

Vitamin C or L-ascorbic acid is a naturally occurring antioxidant that helps with skin lightening. It prevents tyrosinase from converting tyrosine to melanin. Vitamin C is also favored for its anti-inflammatory and photoprotective properties. However, L-ascorbic acid is highly unstable and rapidly oxidized. It is not used in the treatment of PIH.

Stable forms of vitamin C include magnesium ascorbyl phosphate or sodium ascorbyl phosphate. For safe and effective results, consider a dermatologist-formulated serum VITA C GOLD™ Serum,a formulation tested for bio-activity in a laboratory.

As seen above, there are various treatment options to treat common hyperpigmentation disorders. Recognizing the underlying cause for pigmentation is critical for proper treatment and choosing the best-suited therapy. Visit an accredited dermatologist for effective and safe treatments catered to your condition.

© 2018 TWL Specialist Skin and Laser Centre. All rights reserved.

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Meet with Dr. Teo Wan Lin, an accredited dermatologist at TWL Specialist Skin & Laser Centre, for a thorough consultation to determine the most suitable treatment for your skin.

To book an appointment with Dr. Teo, call us at +65 6355 0522, or email appt@twlskin.com. Alternatively, you may fill up our contact form here.