Dark spots are also called hyperpigmentation. It is caused due to acne scars, excessive sun exposure, and hormonal changes. Patches appear on the skin, and they seem to be darker than the surrounding skin. It often occurs when there is an increased production of melanin. It is treated by taking Hydroquinone creams and Retinoid solutions. Another option that is used to lighten the dark spot is laser treatment and chemical exfoliators.
Melasma (Dark Patches on Face): How to Get Rid of Them
Melasma is one of the most common hyperpigmentation disorders that results in dark patches on sun-exposed areas. Read the article to know more.

Dark Spots in Children: An Overview
Dark spots in children are usually harmless, but monitoring and protection are key to maintaining healthy skin.