What is hyperpigmentation or melasma?

Normal skin contains cells called melanocytes that produce the brown skin-coloring pigment melanin. There are several conditions in which melanocytes are either abnormal or abnormally distributed. Most skin conditions that cause discoloration are harmless. A pale area of the skin is the result of fewer or less active melanocytes than usual, whereas a darker area (or area that tans more easily) indicates more numerous or more active melanocytes.

What about the red/brown marks left behind after acne?

These kind of marks are postinflammatory hyperpigmented lesions and are located at the site of a skin trauma after it has healed.They can result from acne, bites, burns or skin infections. The lesions range from light brown to black in colour. Lesions may become darker if exposed to sunlight (UV rays). Postinflammatory hyperpigmentation can occur in anyone, but is more common in darker skinned individuals, in whom the colour tends to be more intense and persists for a longer period.

What is the cause of postinflammatory hyperpigmentation?

Inflammatory responses of the skin to disease or trauma results in the release and oxidation of arachidonic acid. The resulting reaction alters the activity of immune cells and melanocytes. Melanocytes produce more melanin (skin colour pigment), which is transferred to surrounding skin cells. This is known as epidermal hypermelanosis and can be treated with skin care products. Another cause of post inflammatory hyperpigmentation is dermal hypermelanosis. This form of hyperpigmentation occurs in the deeper layers of skin and is caused when inflammation disrupts the basal cell layer. This causes melanin pigment to be released into the papillary dermis (the top part of the dermis).Unfortunatley, this form of cell damage is difficult to treat with skin care products.

What about marks caused by sun damage?

Larger flat brown spots on the face and hands arising in middle age also result from sun damage exposure. Unlike freckles they tend to persist for long periods and don't disappear in the winter (though they may fade). Commonly known as age spots or liver spots, the correct term for a single lesion is benign solar lentigo (plural lentigines). Lentigines are common in those with fair skin but are frequently seen in those who tan easily or have naturally dark skin. Lentigines are due to accumulated pigment cells (melanocytic hyperplasia). If the brown marks are scaly, they may be solar keratoses (sun damage) or seborrhoeic keratoses (senile warts). These are usually treated by cryotherapy. It is important to distinguish the benign solar lentigo from an early malignant melanoma, the lentigo maligna. If the freckle has arisen recently, is made up of more than one colour or has irregular borders or if you have any doubts, see your dermatologist for advice.