Cystic acne forms when the infection that causes a pimple moves to deeper tissue and causes the pore to fill with pus, according to WebMD. As of 2014, no one is certain of the exact cause of acne, but hormones and genetics are two factors that affect its development. During the teen years, androgens, the hormones related to acne formation, increase.
If one or both parents had acne as teens, their child is at a greater risk for developing the condition, according to WebMD. Men have a greater chance of developing cystic acne. It generally occurs during the teens or the early 20; however, it is reported in children as young as 8 and adults as old as 50. The cysts are most likely to form on the face, chest, upper arm and shoulders of a man or on a woman's lower face.
Moderate to severe cystic acne requires treatment by a dermatologist, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases. The treatment regimen may include topical or oral medications. Topical medications include antibiotics, vitamin A derivatives and medications to stop the specific bacteria that cause pimples or reduce inflammation. In some cases, the doctor combines topical medications with oral antibiotics to control bacteria and reduce inflammation.