Acne, or “acne vulgaris”, is an oily skin condition where skin’s sebaceous glands produce excess sebum. This causes pores to become clogged with dead cells and sebum. Sometimes, the process stops there, resulting in blackheads and whiteheads. This is known as “retentional acne”. In more severe cases, bacteria multiply in the trapped sebum and cause inflammation in the skin, resulting in superficial pimples called pustules, or deeper, hard and painful lesions called nodules and cysts. This is called “inflammatory acne”.