Acne is a disease in which the hair follicles on your skin become clogged and infected. This results in one of the three types of acne lesions to form. The production of excess sebum is the culprit. It causes the follicles to become blocked. The medical community is still uncertain as to what triggers this excess production. Sebum is produced by the sebaceous oil gland and everybody needs a small amount to achieve healthy skin. Sebum helps protects the skin from harmful bacteria by washing it away. Types of Acne Lesions: The three types of acne lesions are whiteheads & blackheads (also known as closed and open comedones respectively), papules & pustules, and cysts. Whiteheads as the name suggests, look like white bumps. They form under the skin and never reach the surface. This makes them very hard to eliminate. Blackheads grow upward and break the skins surface. This enlarged follicle and the oxidation of the dead cells, sebum, and bacteria have a black color, hence the name. Papules form when a whitehead burst and the bacteria spreads to the surrounding tissues under the skin. This causes your body’s immune system to increase its fight on the infection making the inflammation worse. They appear as small, firm, red bumps. Pustules form as the body’s immune system continues to fight the infection by sending pus to the area. They appear similar to a papules with the addition of a yellowish white head. Cysts are the third and final type of acne lesion. They form when a pustule worsens and expands further down under the skins surface. They appear red or purple and are very painful. This is the most serious of all types of acne lesions. Types of Acne: Acne can not only be classified by the types of acne lesions, but further broken down by acne type; depending on what types of lesions you have. People whose acne consists of whiteheads and blackheads would have what is called comedonal acne. A mix of blackheads, whiteheads, papules and pustules acne lesions is called acne vulgaris and is the most common type of acne. The third type of acne is called cystic acne and it is when someone has all three types of acne lesions with numerous cysts. Who Can Get Acne: While most people associate acne with teens, anybody can experience some type of acne at any age. That said certain groups of people are more likely to experience acne. They include teens, people under stress, people who have a family history of the disease, people taking certain drugs and adult women.