Epidemiological studies of the influence of sunlight on the skin.

We examined and interviewed 809 randomly selected individuals (56% women and 44% men, mean age 44 years) from 4 Swedish cities; 1.7% had the sun-reactive skin type I, 26.2% type II, 61.3% type III and 10.7% type IV. Some variations in the distribution of skin types were found between the cities. One hundred subjects (12.4%), mostly women (p less than 0.001), had a history of polymorphous light eruption. People with skin type IV had significantly fewer facial skin problems than the rest of the subjects (p less than 0.05). The majority of subjects with atopic eczema, acne vulgaris or seborrheic dermatitis experienced improvement after exposure to sunlight. Individuals with rosacea also experienced improvement more often than impairment from exposure to sunlight. Facial telangiectases occurred in 57% of the subjects, unilaterally in 8.5% of the cases. The occurrence of telangiectases increased with increasing age (p less than 0.001), increasing sunbathing (p less than 0.01) and poor pigmentation ability (p less than 0.05).