‘Skin pigmentation’, also known as ‘skin discoloration’, is a term used to describe disorders that cause patches of skin to appear lighter or darker than normal, or blotchy and discolored.
Skin discoloration occurs because the body produces either too much or too little melanin, the pigment that gives color to our hair, skin and eyes. Melanin is important to our well-being. It protects the body by absorbing ultraviolet light.
Scientists are still studying the reasons why such skin disorders occur. In some cases there are obvious causes such as sun exposure, drug reactions, hormones, skin trauma or genetic inheritance. In other cases, the reason is not so clear.
Pigmentation, appearing as brown patches, can be triggered by ultraviolet (UV) light from the sun. The first method of treating skin pigmentation is to prevent its appearance, or its worsening, by daily application of sunscreen. UV exposure from sunlight or sun beds will invariably worsen any existing pigmentation and promote further pigmentation, so protection from sunlight is essential. The risk of skin cancers also rises with increasing exposure to UV rays.
Dermatologists recommend physical sunscreens as opposed to chemical sunscreens. Physical sunscreens contain titanium dioxide and zinc oxide. These are not absorbed by the skin, and they provide long lasting protection throughout the day.
Chemical sunscreens with chemical ingredients such as para-aminobenzoic acid need reapplication after two hours. They are absorbed into the skin. Studies have found that these chemicals penetrate the bloodstream and can be found in the liver soon after you apply them. There is some debate about whether such products pose a health risk.
Make sure you apply sunscreen liberally, all over the exposed skin, without missing any spots. Sunscreen should be applied every day, even if the day is cloudy, or overcast. As long as there is sunlight to see by, UV light is still present. Avoid direct sunlight, especially during the middle of the day. Seek shade when possible, and wear a hat and protective clothing.
Make your own sunscreen at home. Visit our ‘Recipes’ section on page 249 of ‘Beauty: The Ultimate Cosmetic Makeover Guide. Book 1: Face and Skin.’
Types of skin discoloration
Many skin discoloration disorders have specific names. Some examples follow.
This term refers to the darkening of an area of skin or nails caused by increased melanin.
Vitiligo is a condition that causes depigmentation of parts of the skin. It occurs when skin pigment cells die or are unable to function. The cause of vitiligo, aside from cases of contact with certain chemicals, is unknown, but research suggests it may arise from autoimmune, genetic, oxidative stress, neural, or viral causes. The incidence worldwide is less than 1%.
Poikiloderma of Civatte
‘Poikiloderma of Civatte’ is a reddish brown mottled discoloration on the sides of the neck, which is more commonly seen in women, particularly fair-skinned women.
Poikiloderma is best treated with the Gemini Laser or Pulsed Dye Laser, two of the lasers listed in “Skin Therapy: laser skin therapies” on page 205. This treatment helps to reduce the pigmentation and close off any superficial capillaries causing the redness. The wavelengths from these lasers are specifically attracted to the capillaries and pigmentation, and hence normal skin is relatively unaffected.
Solar (actinic) Keratosis
Solar keratosis lesions are also known as ‘actinic’ lesions. They look like scaly, red patches on the skin, and they tend to appear after the skin has been regularly exposed to sunlight over a long period, such as several years, because sun damage is cumulative. Fairer skin types are more susceptible to this type of skin discoloration.
The treatment of solar keratosis is more than cosmetic – it is also necessary for good health, because the lesions are pre-cancerous.
Melasma is a tan or dark skin discoloration. Although it can affect anyone, melasma is particularly common in women, especially pregnant women (when it is known as ‘the mask of pregnancy’) and those who are taking contraceptives or hormone replacement therapy (HRT) medications. Melasma is also common in pre-menopausal women. It is thought to be enhanced by surges in certain hormones.
The symptoms of melasma are dark, irregular well-demarcated hyperpigmented spots or patches commonly found on the upper cheek, nose, lips, upper lip, and forehead. These patches often develop gradually over time. Melasma does not cause any other symptoms beyond the discoloration.
Researchers think that melasma is caused by female sex hormones stimulating melanocytes (cells in the epidermal layer of skin that produce the melanin pigment) to produce more melanin pigments when sunlight touches the skin.
Women with a light brown skin type who live in sunny regions are particularly susceptible to developing this condition. It also runs in families and is more common in people with thyroid disease. Stress may be another cause. Other rare causes of melasma include allergic reaction to medications and cosmetics.
Freckles are clusters of concentrated melanin which are most often visible on people with a fair complexion. In contrast to lentigines and moles, these spots of color do not have an increased number of melanin producing cells (melanocytes).
Flat, purplish patches of skin are called ‘purpura’. This condition occurs when tiny blood vessels (capillaries) break, leaking blood into the skin. In older people, the condition is called ‘senile purpura’ or ‘actinic purpura’. Purpura looks like a rash that may appear red at first and gradually turns brown or purple.
There is no specific treatment for this condition. People who have it should avoid vigorous rubbing of the skin, or anything else that may damage the capillaries. Creams that soften the skin may be useful. Some physicians also recommend applying vitamin C serum, but as yet no study has confirmed the efficacy of this.
Lentigines, including sunspots and liver spots.
A lentigo (plural lentigines) is a small pigmented spot on the skin with a clearly defined edge, surrounded by skin that appears normal. It is a harmless increase in the number of melanocytes (skin color cells).
Lentigines are distinct from moles (melanocytic nevi). They are also different from freckles. Freckles have a relatively normal number of melanocytes but an increased amount of melanin. A lentigo has an increased number of melanocytes. Freckles will increase in number and darkness when they receive more sunlight, whereas lentigines will stay the same color regardless of sunlight exposure.
Sunspots or ‘solar lentigines’ are dark (and sometimes light) patches on the skin. These can be a variety of shapes and colors and develop anywhere on the skin, though they are most common on the hands and face. People of all ages are prone to these spots, though lighter skinned individuals are more likely to develop them.
The chief cause of sunspots is constant exposure to sunlight, although yeast, natural pigmentation, fungus and certain skin disorders can also play a part.
Long periods of sun exposure can also increase your risk of damaging your skin and developing skin cancer.
Liver spots are lentigines that are also known as ‘sun-induced pigmented lesions’. They look like flat, brown spots on the skin. In spite of their name, they are not associated with the liver. They often appear as we age, and usually on the hands and face. As time passes, liver spots frequently become larger and darker.
Your age, skin type and the amount of time you have spent in the sun without protection will determine how many liver spots appear on your skin, and how big and how dark they become. Liver spots are harmless, but have your skin checked by a doctor every year, because you should beware of lentigo maligna, which is an early sign of melanoma. Liver spots are harmless, although most people prefer their skin tone to be even and youthful in appearance. Treatments may include the following:
- Trichloroacetic acid (a chemical peel).
- Tretinoin (retin A) alone, or in combination with mequinol (solage). Tretinoin is a form of vitamin A.
- Professional freezing with liquid nitrogen (cryotherapy).
- Laser treatment is effective in eliminating many liver spots in one treatment. Laser treatment may be more effective than cryotherapy and may have fewer side effects.
- Bleaching creams are widely available, but they are not as effective as a chemical peel. High concentrations of the bleaching ingredient can cause permanent loss of skin color.
To find out more about the wide range of treatments for skin discoloration including topical agents (creams) for fading dark skin patches, start reading on page 64 of ‘Beauty: The Ultimate Cosmetic Makeover Guide. Book 1: Face and Skin’.by