Acne is mostly inherited, not a hygiene failure
About eight in ten cases track back to genes, not dirty skin or too little sun. Androgens push oil glands harder, a skin bacterium piles on, and by 2015 roughly 633 million people worldwide had acne—yet rural populations often report less of it than industrial ones.
Acne vulgaris starts when dead cells and sebum plug hair follicles. The result is blackheads, whiteheads, pimples, oily skin, and sometimes scars, mainly where oil glands are densest: face, upper chest, and back. Genetics explain most of the risk—about 80 percent in one common estimate, and twin work puts heritability near 81 percent. Cleanliness and sunlight are not linked to the condition. Diet and smoking remain murky; high-glycemic eating shows mixed but sometimes helpful trial results, while dairy milk has only weak observational ties.
Hormones are the usual accelerant. Androgens such as testosterone, DHT, and DHEA enlarge follicle glands and raise sebum output, especially in puberty and around menstrual cycles. People with complete androgen insensitivity or Laron syndrome almost never develop acne, which underlines how central those signals are. Overgrowth of Cutibacterium acnes (formerly Propionibacterium acnes) is another frequent player, though which strains matter and how they arrive is still unsettled. Six lesion types are usually listed: blackheads, whiteheads, papules, pustules, nodules, and cysts—though true cysts are rare, and severe nodular acne is now the preferred label for the worst inflammatory cases.
The scale is huge. In 2015 acne ranked as the world’s eighth-most common chronic disease, touching about 633 million people. An estimated 80–90 percent of Western teenagers get it; nearly half of those affected still deal with it in their twenties and thirties. Scarring hits an estimated 95 percent of people with acne vulgaris, and about three-quarters of those scars are atrophic—ice-pick, boxcar, or rolling. Psychologically, the visible change can feed anxiety, low confidence, and in extreme cases depression. Topical acids and peroxides are common first moves; antibiotics and retinoids come in skin or oral forms; birth-control pills can help some women; and isotretinoin is described as the most effective medicine for severe disease—reserved carefully because of its potency.
Source: Acne
