Follicle fallout is another possible cause of acne. When dead cells within the follicle shed more rapidly, they mix with the extra sebum, stopping the renewal process, resulting in acne. Bacteria or propronibacterium plays a role in acne formation. As a follicle is plugged, bacteria begins to quickly multiply causing a chemical reaction known as inflammation. Inflammation is what causes pimples to become red, painful, and swollen.
There are also many different types of acne. Some examples are acne rosacea and acne vulgaris. The basic types of acne are comedones, papules, pustules, nodules, and cysts which can occur on the face, neck, back, chest, and shoulders. Comedones are considered to be the only form of non-inflammatory acne. A closed comedo is called a whitehead pimple because they usually appear as small white bumps. Comedones occur if a plugged follicle remains below the skin’s surface. Open comedo is called a blackhead pimple because it has a dark appearance which is due to a follicle being pushed above the skin’s surface. Papules, which areconsidered the mildest form of inflammatory acne, appear as a small solid bumps that can sometimes be tender. Pustules are small round lesions with visible pus. They are caused by the chemical irritation from fatty free acids. Nodules are large, extremely painful inflamed pus-filled lesions lodged deep within the skin. Nodules develop when the inside of a comedo spills into the surrounding skin, causing the immune system to produce pus. Cysts are nodules that have become severely inflammed lesions. They can last for weeks or even months. The lesion usually hardens, becoming a deep cyst. Nodules and cysts can result in deep acne scarring.