Whiteheads occur due to sebum, oils and cellular fragments, which combine and become rigid to form unbreakable plugs inside the hair follicle. Whiteheads are closed from the top of the skin by the cellular fragments at the follicle opening. Due to the closed top surface, whiteheads are not exposed to oxygen. Oxidization does not take place and the whiteheads do not turn brown. They appear light yellow in color and are also termed as milia. In combination with bacteria, these whiteheads can cause acne and in severe cases lead to cystic acne.
