Synonyms of age spots include sun spots, solar lentigines, senile lentigines, and liver spots. Age spots are prevalent in low-grade phototype, thought to affect more than 90% of whites older than 60 years, and is linked strongly to sun exposure and age. They are presented as yellow–light brown to black macules on surfaces of the skin exposed to the sun (face, upper back, forearms, dorsum of the hands). Histologically, age spots are characterized by the presence of elongated epidermal rete ridges with heavy pigmentation in the basal layer. Electron microscopy revealed an increase in the number of active melanocytes and number and size of the melanosomal complexes in keratinocytes. Some have reported the presence of giant melanosomal complexes in melanocytes. Keratinocyte defects can be expected because an “age spot” persists even with differentiation, thus indicating that the progeny of keratinocytes persists in perpetuation of the “age spot.” A keratinocyte memory can be postulated. Basement membrane defects are possible with diffusion of melanin into the dermis or transgression of melanin-bearing keratinocytes into the dermis. Treatment options include hydroquinone (2–4%), tretinoin (0.05–0.1%), tazarotene (0.1%), adapalene (0.1–0.3%), azealic acid, and kojic acid. Laser treatment and intense pulsed light treatment have also shown to be effective.

Source: Dermatologic, Cosmeceutic and Cosmetic development - Kenneth A. Walters, Michael S. Roberts

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