Brown spots on skin are called hyperpigmentation, chloasma, or melasma, and can appear for several reasons. One repercussion of sun damage is areas of skin discoloration known as solar lentigenes, more popularly called liver spots, sun spots, or age spots. They are definitely not associated with the liver, but they often have everything to do with unprotected sun exposure. On lighter skin types, solar lentigenes emerge as small brown patches of freckling that grow over time. On women with darker skin tones, they appear as small patches of ashen-gray skin that tend to enlarge over time.
Brown or ashen patches of skin can also occur due to birth-control pills, pregnancy, or estrogen replacement therapy. In those instances, the discoloration is referred to as pregnancy masking or hormone masking.
Regardless of the source, the issue is the same: site-specific, increased melanin production, or hyperpigmentation. Melanin is the pigment or coloring agent of skin. It is created by melanin synthesis, a complex process controlled partly by an enzyme called tyrosinase.
There are many products and ingredients to choose from when trying to reduce skin discolorations. When it comes to selecting treatment for these areas, the most important thing to realize is that it takes experimenting to find what works for you. Hydroquinone and sunscreen are the two options that have the most research and proof of efficacy, and certainly nothing is as important as sunscreen, but that doesn’t diminish other choices depending on your preferences or experience.
Another important factor to consider is the depth of the discolored pigment within the skin. If the discoloration is superficial then topical agents along with sunscreen can make a significant impact. If the discolorations are large, deeper, and more evident, then more penetrating medical procedures such as laser removal, IPL treatments (intense pulsed light), and chemical peels should be a consideration.
It is also important to keep in mind that even if you do have a medical procedure to remove or reduce the appearance of skin discolorations you would still need to maintain sun protection to keep them from coming back (and to discourage new ones from appearing).
That would mean diligent use of a sunscreen along with other topical, melanin-inhibiting products such as hydroquinone in 2% to 4% concentrations, a prescription retinoid such as tretinoin, azelaic acid in 15% to 20% concentrations, or products containing arbutin and vitamin C.