As you know by now, acne is caused by an overproduction of sebum in the sebaceous glands. The result: clogged pores and blemished skin. These blockages cause normally harmless bacteria to multiply and cause inflammation. In truth, however, countless other factors play an important role. Some of them can’t be influenced, but others can. The things that can be influenced include: Smoking, a high weight, certain medications or an unbalanced diet.