The production of melanin is called melanogenesis which causes the skin to visibly “tan” after exposure to UV radiation. Melanin can effectively absorb 99.9% of UV radiation and, because of this property, it is thought to protect the skin from the damage caused by UVB radiation.
Hyperpigmentation occurs when there is an excess production and deposition of melanin in some areas of the skin causing it to become darker than the surrounding skin. It is a condition that affects both men and women and is more common in people with non-Caucasian or olive skin type.
Hyperpigmentation can be triggered by overexposure to the sun, skin trauma or injury such as acne, hormonal imbalances, birth control pills, pregnancy, certain diseases or even a photoxic reaction to perfumed items.
The manufacture of melanin is largely influenced by the body’s endocrine system. The endocrine system sends chemical messengers or hormones to the body. One of these hormones is a melanocyte-stimulating hormone called MSH. MSH stimulates the production of melanin in the skin and can be seen in conditions such as Nelson’s Syndrome and Addison’s disease.
COMMON TYPES OF HYPERPIGMENTATION
Melasma is a common form of hyperpigmentation which is mainly seen in women, with only 10% of men being affected. Melasma can often be seen in a butterfly pattern of dark patches on the nose, cheekbones, upper lip and sometimes on the forehead. It is common among women taking birth control pills and exposure to sunlight can make the patches become darker and more prominent.
Chloasma is a type of hyperpigmentation that can affect pregnant women, showing as dark patches on the face. It is often called the “mask of pregnancy” because of this.
Freckles or Ephelides are also common and can affect both men and women equally. People with fair skin or red hair are more predisposed to freckles but they can also be caused by hereditary factors. Certain diseases, such as xeroderma pigmentosum, can cause extreme sensitivity to ultraviolet light which leads to freckling.
Brown spots or solar lentigines are larger than freckles and are genrally referred to as liver spots or age spots. These can be flat or slightly raised spots of hyperpigmentation which occur on the face or body. Brown spots are commonly caused by years of exposure to the sun’s UV rays and are more likely to appear on areas of the skin that have been the most exposed to the sun.
Post Inflammatory Hyperpigmentation (PIH) is a type of hyperpigmentation that can be triggered by some kind of trauma, allergic reaction or infection of the skin. As the skin heals it secretes chemicals called cytokines which help new skin to form in the damaged area. These cytokines can sometimes stimulate the melanocytes, where melanin is formed, causing the skin to become darker. A common cause of of post-inflammatory skin hyperpigmentation is acne, but any sort of skin injury can cause this condition, as well as other skin conditions, such as eczema.
There are a number of different treatments for hyperpigmentation which include treatments designed to lighten the skin.
- The first line of defence is photo-protection which means protecting your skin from the sun, using a sunscreen and wearing long-sleeved clothing and a wide-brimmed hat.
- Topical whitening creams can be used to inhibit the action of the enzyme” tyrosinase” in the skin. Tyrosinase is the enzyme that is responsible for melanin production. Active ingredients such as hydroquinone, azelaic acid, kojic acid, arbutin, and certain licorice extracts can inhibit the action of tyrosinase and effectively lighten the areas of hyperpigmentation.
Skin whitening creams like Meladerm may contain a number of these skin whitening ingredients.
- Hyperpigmentation can be treated with chemical peels that use compounds like trichloroacetic acid, hydroquinone (2-4 percent concentration), glycolic acid or tazarotene. Microdermabrasion involves wearing away the outer skin layers with a rapidly spinning brush. It can also be an effective treatment for removing hyperpigmentation, while freezing spots with liquid nitrogen and laser re-surfacing are more advanced and costly procedures.
These treatments should only be given by experts, so please consult your dermatologist about these before proceeding. If done incorrectly, chemical peels and laser treatments can sometimes make the hyperpigmentation worse.