Pigmentation is what gives the skin its color. Hyper-pigmentation is a common, usually harmless condition in which patches of skin become darker in color than the normal surrounding skin. When a person is healthy, his or her skin will appear uniform in color. This darkening occurs when an excess of melanin, the brown pigment that produces normal skin color, forms deposits in the skin. Exposure to sunlight is a major cause of hyperpigmentaion, and will darken already hyperpigmented areas. In the case of illness or injury, the person's skin may change color, becoming darker (hyperpigmentation) or lighter (hypopigmentation). Now, you might be asking yourself what does melanin have to do with ultra-violet light? Well, the body uses melanin to protect the developing skin cells. One of the things that melanin does is it actually absorbs ultraviolet radiation, and upon UV exposure can create more, or too much. Melanin is constantly absorbing the ultraviolet rays of the sun. Ultraviolet radiation has been found to be dangerous to cellular DNA. When living tissue is exposed to ultraviolet radiation it actually causes cellular changes.
Lentigines, Age spots, or "liver" spots are a common form of hyperpigmentation. They occur due to sun damage, and are referred to by doctors as solar lentigines. They are distinguished from freckles based on the proliferation of melanocytes (melanin-producing cells). Unlike freckles, they usually stay dark whether exposed to sun or not. Freckles usually lighten a bit when NOT exposed to sun. Generally, freckles, age spots, and other darkened skin patches can become darker or more pronounced when skin is exposed to the sun. This happens because melanin absorbs the energy of the sun's harmful ultraviolet rays in order to protect the skin from overexposure. Melanin acts as a filter (or, as I tell my clients, an umbrella) to prevent damage to the delicate deeper layers of the skin, from penetration of ultraviolet light. Freckles have a relatively normal number of melanocytes but an increased amount of melanin. A lentigo, or age spot has an increased number of melanocytes. Freckles are small brown spots that can appear anywhere on the body, but are most common on the face and arms. Freckles are an inherited characteristic, and will increase in number and darkness with sunlight exposure, whereas lentigines/age spots will stay stable in their color regardless of sunlight exposure.
PIH or Post-inflammatory hyperpigmentation results from trauma to the skin. It occurs with equal incidence in males and females; and can occur in persons of any age. The distribution of the hyper-melanotic (over-pigmented) lesions depends on the location of the original inflammatory cause. The color of the lesions ranges from light brown to black, with a lighter brown appearance if the pigment is usually within the epidermis (upper layers of the skin) and a darker gray to bluish appearance - if lesions contain dermal melanin (deeper layers of live tissue where the skin cells originate). Internationally, post inflammatory hyperpigmentation is a common inflammatory response of the skin, developing more commonly in darker skin. Additionally, despite their lighter skin color, certain Asians (from Pacific rim countries such as Japan, Taiwan, China) are also more susceptible to developing PIH.
Pregnancy and Hormonal melasmaor chloasma is similar in appearance to age spots but are larger areas of darkened skin that appear most often as a result of hormonal changes. Pregnancy, for example, can trigger overproduction of melanin that causes the "mask of pregnancy" on the face and darkened skin on the abdomen and other areas of the body. Women who take birth control pills or hormonal supplements may also develop hyper-pigmentation because their bodies undergo similar kinds of hormonal changes similar to that of pregnancy. If one is really bothered by the pigmentation, discontinuing use of birth control pills should be considered. The darkening may lessen or gradually go away, however, this may take up to a year.
Illness/Medications/ Stress/Oxidative stress (caused by free radical damage) and intrinsic & extrinsic stressors as well as common inflammatory diseases such as Addison's disease (decreased function of the adrenal gland), lichen planus, lupus erythematosus, atopic dermatitis), may cause a greater production of melanin hyperpigmentation.
Post-inflammatory hyperpigmentation can darken with exposure to UV light and various chemicals. Hyperpigmentation can also be caused by various drugs (some antibiotics, antiarrhythmics, antimalarial drugs, tetracycline, bleomycin, doxorubicin, 5-fluorouracil, busulfan, arsenicals, silver, gold, hormones, and clofazimine). Concomitant with PIH, medications might aslo induce allergic reactions, infections, trauma, and phototoxic (extreme sensitivity to sunlight) eruptions.
There are other treatments that may induce postinflammatory hyperpigmentation. PIH can also be seen following treatment with a number of electromagnetic devices such as deep penetration ultrasound (ultherapy), radio-frequency, light-emitting diodes (LED) and visible light. There is always a risk of hyperpigmentation following microdermabrasion treatment. Fractional laser photothermolysis (laser hair/pigment ‘removal’) occasionally induces post-inflammatory hyperpigmentation.Aggressive cleansing, over-exfoliation, picking, repetitious inflammatory treatments, trauma and surgery can also be causes of PIH.
(Did you know that we see more hyperpigmentation on the left side of the face - this is because it is the side of your face that gets more sun exposure, usually related to driving.)
Check back soon for new informative blog articles regarding effective and preventative treatments for pigmentation problems.