Blackheads are a symptom of acne in which the pores of the skin become blocked with a waxy substance called sebum. Sebum aids in protecting the skin and keeping it hydrated. However, when sebum is overproduced it blends with dead skin cells and blocks the pores, where it is then oxidised and turns black in colour. The light reflecting on the blackhead can also make it appear incredibly dark.
Blackheads and whiteheads are very similar. The only variation is that the hair follicle is closed with whiteheads and open with blackheads.
Blackheads are incredibly common in teenagers, but people of all ages are known to experience them. Blackheads are most commonly found on the side of the nose, forehead and chin. They can also be found on the ears, shoulders and back.