A closed comedone, also known as a whitehead, is a form of acne. Generally, a closed comedone is formed when a pore becomes clogged with dead skin cells, excess oil, and bacteria, thereby leading to inflammation within the pore. The term whitehead comes from the buildup of pus as a result of the inflammation, which forms a white bump under the skin.
Whiteheads are caused by P. Acnes — a type of bacteria that lives on the skin and feeds on the skin’s natural oils. Normally, skin cells are generated within the follicle and then migrate out of the pore. Acne develops when the pore becomes clogged with skin cells that have become trapped within the pore, which in turn traps oil and allows for the growth of bacteria. A closed comedone occurs when the follicle becomes completely blocked, with only a microscopic opening to the air, thereby trapping the infected material in the pore.
In some cases, the closed comedone can develop into more serious forms of acne, including pustules and papules. Pustules are small abscesses in the skin that develop at the site of the closed comedone, which are filled with a large amount of pus. They can occur at the surface of the skin, or deeper within the pore for more severe forms of acne. Papules are filled with solid material that cannot be expelled, and lead to redness and swelling at the site of the closed comedone. Both papules and pustules are more severe forms of acne that can lead to scarring and skin damage.
Simple closed comedones can usually be prevented by maintaining a consistent skincare routine. Regular cleansing and exfoliation helps regulate oil production to control the amount of P. acnes growing on the skin. Additionally, exfoliation can help slough off dead skin cells and prevent buildup of skin cells within a pore.
Closed comedones can usually be treated by over-the-counter acne medication. The most commonly used medications are benzoyl peroxide and salicylic acid. Benzoyl peroxide has an antibacterial effect on the skin, and penetrates deep into the pore to kill P. acnes. It is commonly used to treat acne that occurs deeper within the skin. Benzoyl peroxide is found in a number of products in a range of concentrations, and consumers typically should use the lowest effective concentration to prevent skin irritation.
Salicylic acid helps loosen skin cells within the pore to prevent buildup, and also constricts pore diameter to prevent future buildup of oils. It should be primarily used to treat and prevent comedones at the surface of the skin. A number of acne products contain salicylic acid in a range of concentrations, and consumers typically should use the lowest effective concentration, since salicylic acid can irritate the skin. People with sensitive skin may wish to use acne medication every other day only to prevent further irritation to the skin.