Melasma was an unsolvable issue until recently. It usually strikes women in pregnancy or after childbirth. An increased level of female hormones causes the development of pigmentation, especially in combination with the sun. Oftentimes it appears in women who take contraceptives or a supplemental hormone therapy.
Along with other reasons, sun is the main cause of melasma development. It is considered that sun damages certain pigment cells, which then start producing pigmentation in larger amounts. Female hormones additionally cause the enhanced production of pigmentation. Despite your efforts to avoid the sun and your use of highest protective factors, faces of many women simply darken. This is caused by uvb rays which have greater strength in the summer. Because of the effect of the UVB rays, cells start producing larger quantities of pigment. Pigment cells have areas on their surface , receptors, on which hormones are linked to. By linking female hormones, especially estrogen, onto the receptors an increase of pigment production begins. Other factors which cause pigmentation development exist but they are not so well known yet.
Blood vessels play their part in melasma development as well. Once the pigmentation is removed, on the forehead and temples there will still be visible blood vessels. Sun exposure and subsequent skin darkening causes the development of blood vessels and thinning of the skin, which causes the blood vessels to be more visible. The skin becomes more brown in color. In other facial areas blood vessels do not have any role in the creation of melasma. If you press the pigmentation on your forehead and it turns to a lighter color the cause are the blood vessels. If that is the case, to cure melasma, blood vessels should be removed as well.
The condition affects the whole face symmetrically, mostly areas which are exposed to the sun the most: forehead, temples, cheeks and areas under the eyes and above the upper lip. Some women only have their upper lip affected which is an aesthetic issue which cannot be hidden and gives you a dirty look.
Men are affected as well but in smaller percentages.
There are three types of melasma: superficial, deep and a combination type. To determine the shape a Wood lamp is used. With the superficial type, the pigmentation is only in the first skin layer, and by lighting the skin with the Wood lamp the pigmentation is more visible. With the deep type the pigmentation is located in the middle skin layer. There are no changes when lighting the skin, because the pigmentation is seen with and without the lamp. With the combination melasma type the pigment is located in both skin layers. Melasma of the forehead has special characteristics, after melasma removal blood vessels which give you a brown looking skin color must be removed as well.