How Acne Forms
The technical explanation of the occurrence of acne is that it is a disease of the pilosebaceous units (PSUs). PSUs are found all over the body and consist of a sebaceous gland connected to a canal, called a follicle, that contains a fine hair. The PSUs are most numerous on the face, upper back and chest. When the PSU is working properly the sebaceous glands make an oily substance called sebum that normally empties onto the skin surface through the opening of the follicle, commonly called a pore. Cells called keratinocytes line the follicle.
The hair, sebum, and keratinocytes that fill the narrow follicle may produce a plug, which is an early sign of acne. The plug prevents sebum from reaching the surface of the skin through a pore. The mixture of oil and cells allows bacteria Propionibacterium acnes (P. acnes) that normally live on the skin to grow in the plugged follicles. These bacteria produce chemicals and enzymes and attract white blood cells that cause inflammation. (Inflammation is a characteristic reaction of tissues to disease or injury and is marked by four signs: swelling, redness, heat, and pain.) When the wall of the plugged follicle breaks down, it spills everything into the nearby skin – sebum, shed skin cells, and bacteria – leading to lesions or pimples.
Acne presents itself in a variety of ways and come with a variety of names to distinguish it.
Whiteheads
The basic acne lesion, called the comedo (KOM-e-do), is simply an enlarged and plugged hair follicle. If the plugged follicle, or comedo, stays beneath the skin, it is called a closed comedo and produces a white bump called a whitehead.
Blackheads
A comedo that reaches the surface of the skin and opens up is called an open comedo or blackhead because it looks black on the skin’s surface. This black discoloration is due to changes in sebum as it is exposed to air. It is not due to dirt.
Papules
These are inflamed lesions that usually appear as small, pink bumps on the skin and can be tender to the touch.
Pustules (pimples)
When the papules are topped by white or yellow pus-filled lesions that may be red at the base they are given the simple name pimples.
Nodules
More severe cases of acne are characterised by large, painful, solid lesions that are lodged deep within the skin.
Cysts
Another severe form of acne presents with deep, painful, pus-filled lesions that can cause scarring.
These different types of acne require differing acne treatments from topical medicine treatments such as creams or washes to oral medication for the more severe forms of acne. The types of acne treatment will be dealt with in another article.
Tags: Acne