This first category is by far the most published acne exposome factor. Main food classes considered as triggering acne are dairy products (especially skim milk) and hyperglycaemic carbohydrates. An average regimen of dairy products has been reported impacting on acne, and one paper indicated that cow milk impacts on acne after drinking two glasses per day.
The following androgenic progestins have been identified to cause or worsen acne: desogestrel and 3-cetodesogestrel, levonorgestrel, lynestrenol, norgestrienone, norethisterone, norgestrel, gestodene, norgestimate, and etonogestrel. In contrast to this, chlormadinone acetate, dienogest, drospirenone, and norgestimate oral contraceptive pills have been reported to be beneficial in the treatment of acne. Corticosteroids, halogens, isoniazid, lithium, vitamin B12, immunosuppressants, and certain anticancer agents and radiotherapy have been reported as causing acneiform eruptions.
E.g. cosmetics, mechanical factors
The use of aggressive skin care regimens and inappropriate cosmetics may cause acne flare-ups. These products modify the skin barrier and the skin microbiota balance especially in the sebaceous area, thus activating the innate immunity triggering inflammation.
Mechanical factors comprising rubbing, scrubbing, the use of home devices or medical devices such as sonic brushes, derma rollers, or micro needling systems may trigger acne flare-up.
E.g. air, industrial, and human-dependant pollutants
Air pollutants exert a harmful effect on the skin by increasing oxidative stress inducing severe alterations of the normal functions of lipids, deoxyribonucleic acid, and/or proteins in the human skin.
Acne has been frequently observed in industrial workers after prolonged exposure to certain organic molecules, such as coal, tar, or crude oil.
Tobacco and cannabis use may be considered human-dependent pollutants which may play a role in acne.
Climatic conditions and seasonal variations resulting in a combination of heat, humidity, and intensive ultraviolet rays (UVR) may trigger inflammatory acne flare-up, which have been called acne Tropicana, acne Majorca, or tropical acne.
One of the major environmental factors affecting the skin is ultraviolet radiation. Both UVB and UVA have been reported to cause hyperplasia of the sebaceous gland, thickening of the stratum corneum, increase in sebum secretion and in the number of comedones.
PSYCHOSOCIAL AND LIFESTYLE FACTORS
Modern lifestyle, defined as stressful situations including urban noises, socioeconomic pressures, and light exposure, may play a role in acne.