Melasma is one of the most common skin problems and is characterized by the appearance of pigment spots on the face. It affects the most exposed areas of our skin in the sun, namely: forehead, nose, cheekbones, upper lip, chin. The ratio of affected women to men is 9: 1. It is still the subject of serious scientific debate which are the exact causes of these spots. One of them is is that melasma is inherited and that UV rays are the external factor provoking the formation of free radicals that increase melanogenesis (the formation of more pigment). If I need to specify into the analysis of why females are much more affected, I must note that half of the cases occur or worsen during pregnancy or taking birth control pills.
What is melanin? Where does it accumulate? Who synthesizes it?
Melanin is formed after oxidation of the amino acid tyrosine. It has two essential functions for the human body - it determines the color of the skin and hair and provides basic protection from UV rays. It is produced by cells called melanocytes. They are located among the kertinocytes in the epidermis (the main type of cells in this structure). In melanocytes, melanin is "wrapped" in special structures called melanosomes and then "injected" into epidermal cells. The amount of melanocyte cells in the facial area is about 1200 / sq.mm. In patients with melasma, an increased concentration of melanin is observed in both the epidermis and the dermis.
Why do dark spots form on the face?
Ladies, melasma is extremely affecting our gender, with a female to male ratio of 9: 1. The main reasons for its appearance are genetic predisposition, ultraviolet radiation, pregnancy, hormone therapy, cosmetics and phototoxic drugs. A team of scientists led by Ortonne et al., conducted a study in 324 women with melasma. In 50% of them there is at least one family member with spots on the face. In 42% of them, the first spots appeared during and after pregnancy. 16.2% of women cite taking oral contraceptives as a cause, and 27.2% exposure to the sun without a sunscreen.
The sex hormones estrogen and progesterone stimulate melanocytes to produce more melanin when the skin is exposed to the sun. In addition, examination of skin from an area with melasma revealed that there were more estrogen receptors in these areas. Thus, any hormonal event with a deviation from the normal values of these hormones can lead to the development of melasma in predisposed individuals. In addition, it is absolutely mandatory to test for thyroid hormones, because in women with melasma the risk of developing thyroid disease is four times higher.
What are the therapeutic options?
Hydroquinone remains an established standard in the treatment of dark spots on the skin. It inhibits the enzyme tyrosinase, which is the first enzyme in melanin synthesis. On the other hand, it damages the cell wall of melanocytes and thus reduces the number of pigment cells in the affected area. It is used alone or in combination with a retinoid and a corticosteroid (Kligman's formula).
Other compounds involved in creams and peels and arbutin, azelaic acid, kojic acid, vitamin C, niacinamide. The main rule in therapy is to first exhaust all possibilities with topical approach, and only in case of failure to seek a solution with a laser. Pico, Alexandrite, PDL lasers have a good effect.
Regardless of the choice of first therapy, the milestone remains sun protection. Products with a wide range of coating against UVA, UVB, blue light should be used. It is desirable during the summer months to have mechanical protection by wearing a hat.
Melasma therapy can be summarized in three steps, which the world's guidelines recommend to follow: 1) hydroquinone or Kligman's formula; 2) chemical peels; 3) lasers. The truth is that the fight is difficult. People who live in warm countries with long sunny days should apply sunscreen daily. Otherwise the melasma recurs. The good news is that melasma is a benign pigment disorder that is believed to have a lower risk of developing malignant melanoma.