No one factor causes acne. Acne happens when oil (sebaceous) glands come to life around puberty stimulated by male hormones from the adrenal glands of both boys and girls. Oil is a natural substance which lubricates and protects the skin, and under certain circumstances, cells that are close to the surface block the openings of sebaceous glands and cause a buildup of oil underneath. This oil stimulates bacteria, (which live in everyone’s skin and generally cause no problems), to multiply and cause surrounding tissues to become inflamed….

We know that there are 4 main factors that are cause acne

1. Hormones – The effect of androgen hormone in the oil producing glands of the skin , leads to an excess of oil production.
   Androgen hormone increases during the teenage years, the menstrual cycle, pregnancy, with the use of certain contraceptions and at times of stress.
2. Skin cell production – An increase in skin cell production and a decrease in skin cell shedding, results in the blockages of the pores and leads to the production of blackheads and white heads.
3. Oil production – The combination of excessive oil production and blocked pores provides the perfect breeding ground for the acne bacteria , Propionibacterium acnes(P.acne) 
4. Bacterial overgrowth – An overgrowth of P.acne bacteria results in an inflammatory response causing red spots that can be visible as acne.