Your body contains a pigment called melanin, which determines the colour of your skin, hair and eyes. People with darker skin types tend to have more melanin in their skin cells than those with lighter skin.
Imbalances and disorders of the skin can lead to variation in colouration, patterning and blotches.
When skin cells become damaged or unhealthy, extra melanin can produced to help protect your skin or the actual melanin cells can be damaged. As a result, parts of your skin may turn lighter (hypo-pigmentation) or darker (hyperpigmentation), both of which are recognisable skin conditions.
Excess pigmentation can give rise to; melasma, freckles, sunspots and PIH (Post Inflammatory Hyper-pigmentation). PIH can occur as a result of trauma to the skin eg. acne, sun damage, scratching caused by eczema and dermatitis.