What causes melasma?
Melasma is caused when the pigment-producing-cells called the melanocytes become overactive and secrete excess melanin. The excess melanin gets deposited in the outer layer of the skin causing the appearance of dark patches on the surface. It is caused by a varying combination of factors like –
A change in hormones
Melasma could be triggered by hormonal changes like pregnancy, menopause and hormone replacement therapy. The pregnancy induced melasma is called chloasma or the mask of pregnancy and is largely caused due to high levels of progesterone. People suffering from thyroid disease or polycystic ovarian disease also have a greater chance of developing this condition.
People with a genetic predisposition are at an increased risk of developing melasma. Skin pigmentation is originally caused by the UV rays from the sun. Normally the skins natural protection is able to resist the UV rays, but as people grow older, the immunity of the body reduces. This makes it possible for the years of accumulated sun exposure to take its toll on the skin. When this happens, it causes some genetic mutations of the genes that are responsible for the formation of skin color melanin. The genetic mutation experienced in such people can be passed on to their offspring’s and the cycle continues.
Ultraviolet light from the sun stimulates the melanocytes. Even a minimal amount of sun exposure can make melasma relapse. Most people find their melasma worsening in summer.
Recent research has established a link between stress and melasma. Stress can activate the propriomelanocortrin gene that prompts the cells to produce more pigment.
Skin care products that irritate the skin may trigger or worsen melasma.