The picture above is a guy who's 69 years old, but the other half of his face looks much older than that. Turns out being exposed to the sun will make you age prematurely, and its the drastic difference just shows how shocking that can be.
His condition is called unilateral dermatoheliosis, from the Greek dermis and helios, skin and sun. It's also called photoaging, and it results from chronic exposure to the sun's UVA and UVB rays.
The case was discovered and studied by Jennifer R.S. Gordon and Joaquin C. Brieva, dermatologists at Northwestern University, and published in the New England Journal of Medicine:
A 69-year-old man presented with a 25-year history of gradual, asymptomatic thickening and wrinkling of the skin on the left side of his face. The physical examination showed hyperkeratosis with accentuated ridging, multiple open comedones, and areas of nodular elastosis. Histopathological analysis showed an accumulation of elastolytic material in the dermis and the formation of milia within the vellus hair follicles. Findings were consistent with the Favre–Racouchot syndrome of photodamaged skin, known as dermatoheliosis.
The patient reported that he had driven a delivery truck for 28 years. Ultraviolet A (UVA) rays transmit through window glass, penetrating the epidermis and upper layers of dermis. Chronic UVA exposure can result in thickening of the epidermis and stratum corneum, as well as destruction of elastic fibers. This photoaging effect of UVA is contrasted with photocarcinogenesis.
UVB and UVA can cause DNA mutations leading up to skin cancer. Doctors recommend that patients use sun protection and topical retinoids. So, if you're heading to a beach this holiday, remember to slap on some sun screen. [NEJM]