The majority of those who experience acne are teens and adults. From mild breakouts to active acne, it is difficult to pinpoint the exact causes of acne. Acne is a multi-factored condition with 4 distinct causes - increased production of skin oils, including sebum; proliferation of P. acnes bacteria; incomplete skin shedding leading to impacted/clogged pores; irritation and inflammation, including disruption of the cellular walls of pores. Other causes are linked to hormones, poor diet, stress and vitamin deficiency. Your physician can evaluate your acne and recommend a treatment plan.