Blackheads are perhaps one of the most recognisable types of acne and are notable for their dark colour. When found on the skin, they are slightly raised and derive their distinctive appearance from the process of a hair follicle becoming blocked by dead skin cells and excess sebum (oil).
As this skin debris and natural oil come together, they form a bump known as a comedones. Blackheads are created when the skin that sits over this bump opens, exposing it to the air. Like most other variations of acne, blackheads may be triggered by certain hormonal changes, which explains why they are so commonly experienced by teenagers.