Dyschromia
What is dyschromia?
Dyschromia is another word for skin discolouration. This refers to patches of uneven colour that can appear on the skin, generally as a result of sun damage.
Very often, the aim of treating dyschromia is to even out the skin tone, returning it to its original, consistent complexion. But please note: if you have a new, dark spot or area, such as a mole or other growth - or, if an existing one has changed colour, size, or appearance - it is important to have it diagnosed by your dermatologist before attempting to treat it. If there is any change in skin pigmentation that occurs and persists without an obvious cause, it may indicate a more serious condition. If no medical problem is found, however, you are free to consider treatment to even out your skin colour.
The colour of your skin mainly depends upon how much brown pigment (melanin) is mixed in with the blue (from reduced haemoglobin), red (from oxyhaemoglobin) and yellow (from carotenoids in the diet). Melanin is produced from the conversion of an amino acid through a complex series of chemical processes in the skin cells. It's primarily the interplay between two main factors that decides the amount of brown pigment: first, one's initial colour from birth and, second, one's degree of ultraviolet radiation (tanning) from the sun. Other factors include heat, heavy metals, hormones and trauma through ionizing radiation. Temporary or permanent hyperpigmentation (increase in pigment production) and/or hypopigmentation (decrease in pigment production) can result from changes in any of these factors.
Pigment changes can result from other disorders or can exist in their own right. Mottling, or mottled skin, is another type of dyschromia in which changes in the blood vessels cause a patchy appearance. Less commonly, growths of foreign organisms upon the skin can also result in discoloured patches and irregularities.
While skin discolouration is not a medical concern in itself, a low amount of pigment in the skin leaves people more susceptible to skin damage from the sun and the subsequent development of skin cancer. As such, patches of skin with very little or no pigment should be given additional protection, even on people who are predominantly dark-skinned. However, it should be noted that excessive sun exposure is also dangerous for those with darker skin and that all people should take steps to protect themselves from overexposure to the sun.
Skin discolouration can be cosmetically unappealing and, as such, can cause psychological stress for those who are affected by it. Additionally, some pigment changes may indicate a risk for other disorders.
What causes dyschromia?
As mentioned, the causes of dyschromia are many. By far the most common of these, however, is recurrent sunburns or suntans that either results from neglectful exposure to the sun or from uneven application of sunscreen. Otherwise, sensitivity to the sun can be heightened as a side effect from some medications such as certain antibiotics.
Other causes of dyschromia include wounds and minor skin infections. After they've healed, areas of heightened pigmentation remain. While this process of post-inflammatory hyperpigmentation (PIH) affects everyone, it also affects people differently depending on their baseline skin tone. Generally, the darker your complexion, the darker your PIH will be. Discolouration during the healing process can remain in the form of permanent hyperpigmentation in darker-skinned people.
Birthmarks such as café-au-lait spots and Mongolian blue spots and other harmful or harmless spots such as seborrhoeic keratoses (senile warts), moles and malignant melanoma affect the pigmentation of the skin wherever they exist.
Radiation therapy can also cause dyschromia.
What are the available treatments?
Patience is often the most effective measure given that normal skin colour can often spontaneously return.
Topical options
Darkened patches from acne, freckles and resolved skin trauma can be treated with a range of topical bleaching agents such as hydroquinone. In cases of large, hyperpigmented patches (increased colour), bleaching agents can even out the skin tone. Hydroquinone is the oldest method of skin bleaching and has fairly good track record overall. However, some safety concerns have been raised with this product and it should not be used by pregnant women. Rarely, patients who have used it have also seen their dark skin patches become even darker.
Other possibly safer, but less effective, alternatives have since been identified including mitracarpus scaber extract, bearberry extract, licorice extract, beta carotene, gluconic acid, azelaic acid, paper mulberry, kojic acid, vitamin C. Each of these options is derived from natural ingredients and, like hydroquinone, work by circumventing melanin formation, reducing the appearance of darkened patches.
Protection from the sun is essential during the several months of treatment as sun damage will undermine any progress made by the treatment. On the other hand, sun damage may make hyperpigmented skin patches even darker.
Cosmetics and skin dyes are often used to disguise changes in pigment. Make-up can help to hide 'mottled' skin but such an approach will not solve the underlying problem.
Laser and other light-based options (surgical and non-surgical)
Photorejuvenation is new laser or light-based treatment. It delivers stronger pulses of light deep into the innermost layer of skin, injuring then repairing its collagen. Contrary to surgical methods, in photorejuvenation, the outer layer of skin is usually not generally injured and, as such, there are limited visible signs of the procedure. This therapy reduces the appearance of discoloured patches, freckles, sun damage, fine wrinkles, ageing, redness and the dilated capillaries associated with rosacea. A course of several sessions, each a few weeks apart, is typically recommended for best results.
The above light-based treatments are remarkable in their ability to achieve positive results with relatively little discomfort and risk.
Laser resurfacing, also called laser peeling, has been used extensively in the past to effectively treat skin damage and improve the skin's tone and texture.
Another useful technique for blotchy pigmentation is chemical peeling. This has a similar effect to laser resurfacing but doesn't involve the use of lasers. Both techniques can benefit the appearance and texture of mild or severe sun-damaged skin on both the face and body.
Fractional resurfacing is an alternative, relatively non-invasive laser procedure that partially resurfaces the skin by computer-aided technology. Thousands of microscopic holes are driven into the skin, removing these small zones completely but leaving most of the skin intact in any one treatment. This has the effect over a number of treatments of acting like a resurfacing procedure. It rejuvenates the skin in a similar manner to photorejuvenation and can also be used for pigment and texture irregularities. It has been felt that this procedure may be particularly beneficial in treating hormonal pigmentation (melasma).
As is the case with any surgical procedure thorough prior consultation and consideration is required with your qualified practitioner.
Links
- National Organization for Albinism and Hypopigmentation (NOAH), USA, www.albinism.org