Hyperpigmentation (or skin discoloration) is a common, usually harmless condition that makes areas of skin become darker than the surrounding skin. Hyperpigmentation is usually caused by an excess of melanin production. Melanin is the brown pigment that produces skin color. Hyperpigmentation can affect the skin color of people of any race. However, people with darker skin tones are more prone to it.
Some forms of hyperpigmentation are freckles, melasma (also known as chloasma), and age or liver spots (solar lentigines). Age or liver spots are the most common form of hyperpigmentation. They are small dark spots caused by chronic sun exposure. This is why they tend to appear in the face and back of the hands during middle age and keep increasing. Melasma are larger dark spots usually caused by hormonal changes. They are very common in pregnant women.
What Causes Hyperpigmentation?
Hyperpigmentation can be due to various factors:
- Sun damage
- Hormonal changes, such as the ones produced by birth control pills, pregnancy, and menopause.
- Skin diseases and skin injuries, such as acne or burns.
- Medication. Some medicines containing minocycline, bleomycin, amiodarone, tetracycline, chloroquine, cyclophosphamide, or quinacrine produce hyperpigmentation as a side effect.
- Diseases. Hyperpigmentation can also be a symptom of some diseases such as Addison’s disease, Scleroderma, or Porphyria, among others.
Whatever is the cause, sun exposure without using a high SPF sunscreen will always worsen hyperpigmentation.
Treatments For Hyperpigmentation
- Cryotherapy (freezing skin lesions) is useful only for small, well-localized hyperpigmented lesions, such as age spots.
- Laser Resurfacing. The first few layers of damaged skin are removed to leave behind a fresh, evenly toned skin. It is more expensive but effective, although it can have side effects. Many times, doctors recommend to use hyroquinone creams before the laser treatment.
- Intense Pulsed Light (IPL) is a type of laser treatment that eliminates hyperpigmentation by heating up the damaged area. It is fast and effective to remove localized spots. As laser resurfacing, it is expensive and can produce some side effects.
- Chemical Peeling remove the damaged skin layers by increasing cell renewal rate. Hydroxy acids are the main chemicals used in this treatment and it should only be applied by dermatologists.
- Microdermabrasion is a procedure that “sandblast” the skin with aluminum oxide crystals, and other types of mild abrasives to remove the top layer of the skin. This enhances the skin cells growth rate, decreasing the quantity of pigment delivered in the skin and lightening it.
- Oral treatments. Many of them contain L-glutathione. L-glutathione is an antioxidant produced by our body that, besides attacking free radicals, blocks the production of melanin. Others, are L-Cysteine based. L-Cysteine is an amino acid that works to suppress the effects of melanin and boost glutathione levels naturally.
- Topical therapies (creams and lotions). The most commonly used agents in these products are phenols (i.e., hydroquinone, mequinol), retinoids( i.e retinol and tretinoin), alpha-hydroxy acids (i.e., glycolic acid, lactic acid), glabridin (also known as licorice extract), kojic acid, and azelaic acid.
A Little More About Topical Therapies
Hydroquinone based products are widely used. Hydroquinone is very effective in reducing hyperpigmentation. It works by inhibiting the tyrosinase enzyme, thereby preventing the production of melanin. Usually hydroquinine treatments requires several weeks before any significant improvement in the hyperpigmentation (up to six months). Most dermatologists recommend 4% hydroquinone products, only available by prescription. Hidroquinone with up to 2% concentration is available over-the-counter. It has some potential side effects, such as irritation, allergy, and nail discoloration.
Hydroquinone has also been reported to cause ochronosis, a bluish black discoloration of tissue. This side effect is relatively rare with short-term use of low-to-medium concentrations. However, it appears to be relatively frequent after prolonged use of high concentration (5% or more), especially in dark skinned people.
Some studies with mice indicate that high dosis of hydroquinone can cause cancer. However, more research is needed in order to better evaluate those results.
Retinoids reduce hyperpigmentation by accelerating cellular turnover and increasing epidermal exfoliation, which leads to a greater loss of epidermal melanin. Retinoids may also reduce melanin synthesis because when speeding up exfoliation melanine has less time to be produced.
Alpha hydroxy acids (i.e., glycolic acid) speeds up the turnover of epidermal cells and accelerates exfoliation, causing more melanin to be removed.
Glabridin (also known as licorice extract) inhibits melanin production by inhibiting tyrosinase activity. It also has anti-inflammatory properties. However, at the time of this writing, there are no clinical studies as to how glabridin compares to the more established skin lighteners or what its optimal concentrations may be.
Kojic acid is a natural product found in a type of fungi and produced in the fermentation process of rice to make sake. It seems to inhibit melanin production by blocking an enzyme essential to its production.
Kojic acid’s major drawback is that it can cause skin sensitivity and contact dermatitis in some individuals. This may manifest as redness, rashes or even blisters.
Azelaic acid is a component of grains, such as rye, barely, and wheat. Besides being used to treat hyperpigmentation, it is also effective against acne. It is antibacterial, anti-inflammatory and will protect against free radicals too.
Arbutin is a natural and safe hydroquinone derivative. It is found in the leaves of some berry plants.
It has been shown that arbutin is an effective inhibitor of melanine production by blocking Tyrosinase activity.