Many skin changes, such as skin cancer, wrinkles, and age spots are caused by exposure to the sun. This is because the damage caused by the sun is permanent.
DeLeo VA. Sunscreens and photoprotection. In: Bolognia JL, Schaffer JV, Cerroni L, eds. Dermatology. 4th ed. Philadelphia, PA: Elsevier Saunders; 2018:chap 132.
Habif TP. Light-related diseases and disorders of pigmentation. In: Habif TP, ed. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 6th ed. Philadelphia, PA: Elsevier; 2016:chap 19.
U.S. Food and Drug Administration website. Tips to stay safe in the sun: from sunscreen to sunglasses. www.fda.gov/consumers/consumer-updates/tips-stay-safe-sun-sunscreen-sunglasses. Updated February 21, 2019. Accessed April 23, 2019.