Melanin (from the Greek word melas = black) is a natural brownish-black pigment that protects us from solar radiation; it is produced by certain specialised skin cells called “melanocytes” which can “work” in an irregular and discontinuous manner under certain conditions. They form following stimulation of the Tyrosine that catalyses the oxidation of tyrosine into dihydroxyphenylalanine in the melanocytes of the basal layer of the skin.
Sometimes, however, melanin increases in a non-uniform and irregular manner, creating light and dark patches, the so-called hyper-pigmentation or dark spots.
It is important to distinguish between the epidermal hypermelanocytosis (increase in melanocytes) and epidermal hypermelanosis (increase in the amount of melanin). The former refer to, for example, freckles, whilst the latter refer to melasma, cafÃ¨ au lait coloured spots.
An important contribution to the problem of hyperpigmented spots came with the introduction of innovative methods such as Lasers in dermo-surgical procedures which are preceded by the application of specific topical treatments to defragment the melanin pigment of the epidermis and make the spots easier to remove; this applies to the specialised cells such as macrophages and the action of laser that will be proportionately less invasive and more effective.
Prevention: suspension and replacement (where practicable) of pigmentation inducing therapies: There is a long list of drugs that can cause iatrogenic hypermelanosis: among the most common we can find Phenothiazines, Antimalarials, Hydantoins, Antimitotics (Bleomycin), Psoralens, Minocycline, Quinolones , Amiodarones, Clofazimines. The use of fragrances is prohibited (especially those containing bergaptenes), along with long-term exposure to sunlight and UV lamps (UVA – 320/400 nm and UVB – 290/320nm), with careful and constant photo protection.