ABSTRACT
Chronic exposure to ultraviolet (UV) radiation causes skin changes known as photodamage. In addition to loss of elasticity and changes in the skin texture, alterations in skin color and the appearance of pigmented spots are clinical signs of photoaging. Sun damage can induce alteration of the pattern of melanin deposition in normal and neoplastic keratinocytes or proliferation of melanocytes, with subsequent excess of local melanin. With the former category are ephelides (freckles). Solar or senile lentigines and pigmented actinic keratoses represent sun-induced proliferation of keratinocytes with an excess of melanin as well. Among melanocytic proliferation displaying hyperpigmentation and related to sun exposure are sunburn freckles, the psoralen-UVA-induced freckles or lentigines and variants of malignant melanoma.
