Caused by the over-activity of sebaceous glands. They are more numerous sebaceous glands on the face which give rise to eruptions and disturbances when they are overactive, causing acne. With the over secretion of oil in the sebaceous duct, the excess oil enters the oil sac, which expands to retain the oil. When the pores cannot hold anymore, the excess oil oozes out, enlarging the pores in the process. The first result is a blackhead which is like a solid plug. When the tip is exposed to air, it oxidises and turns dark – this is a blackhead. Neglected blackheads will irritate surrounding tissues, resulting in inflammation, which is setting the scene for pimples and acne. Acne includes, whiteheads, blackheads, pustules and cysts. Acne Vulgaris is a violent form of acne.