Hyperpigmentation 

A number of factors can trigger an increase in melanin production, but the main ones are sun exposure, hormonal influences, age and skin injuries or inflammation. 

Hormonal influences are the main cause hyperpigmentation known as melasma or chloasma. It’s particularly common among women and is thought to occur when the female hormones estrogen and progesterone stimulate the overproduction of melanin when skin is exposed to the sun or a side effect or certain hormone treatments. 

Hyperpigmentation is also symptomatic of certain illnesses such as some autoimmune and gastrointestinal diseases, metabolic disorders and vitamin deficiencies. It can also be triggered by medications such as chemotherapy drugs, antibiotics, antimalarials and anti-seizure drugs.