Types of Acne-Comedonal Acne
Comedones are small non-inflammatory lesions, which may be flesh colored, white, or dark bumps that give skin a rough texture and appearance. The bumps are found at the opening of a sebaceous follicle/pore. Comedones form because plugs of sebum and keratin (old skin cells) block the skin pores/ follicles. Comedones form because plugs of sebum and old skin cells block the pores in your skin. The cells lining the sebaceous duct proliferate excessively in acne and may block the sebaceous duct forming a comedone. These may be so small that they are not visible to the naked eye called microcomedones or quite large and deeper called nodules. Comedogenic refers to anything that tends to clog pores and produce comedones. Comedonal acne is a type of acne in which most lesions are comedones such as blackheads and whiteheads and with no other kinds of skin lesions. These are the un-inflamed blackheads and whiteheads that occur on the forehead and chin of those with acne, adult acne or rosacea. The singular is "comedo".
Types of comedones include:
1) Microcomedones, which are so small they cannot be seen without magnification. A microcomedone is a plugged pore and is a prelude to the development of acne. When cells called keratinocytes are abnormally or prolifically formed, they can accumulate within of the follicular duct or tube leading up to the skin surface to deliver sebum. When this happens, enlargement of the follicle occurs. Accumulation of dead cells within the duct leads to a partial clogging or plugging of the follicle/pore. When these dead cells come into contact with bacteria and sebum, a sticky plug is formed and this leads to complete blockage of the follicle. This leads to the formation of the next stage on comedones - blackheads and whiteheads.
2) Open comedones, which are called blackheads. The black color is the result of surface pigment (melanin) rather than dirt. Blackheads are small, dark spots about the size of a pinhead caused by discoloration of the surface of a small plug in the opening of a follicle/pore.
3) Closed comedones are called whiteheads. Whiteheads occur when the follicle is completely blocked. Whiteheads are small white spots about the size of pinheads, which are caused by collections of oil and skin in pores.
4) Macrocomedones are facial closed comedones that are larger than 2-3 mm in diameter. macrocomedones are unsightly lesions that may be resistant to medical treatments and comedone extractors. Light cautery may be used to treat macrocomedones, which are 1 to 3 mm in size; however, its success in larger and chronic lesions is limited.
5) Solar comedones are found on the cheeks and chin of older people, and are thought to be due to sun damage. They occur on areas that have been exposed to sunlight over a long period of time, particularly the cheeks, which may become yellow and leathery The appearance is also known as Favre-Racouchot syndrome. Solar comedones may appear as blackheads or whiteheads. There may also be larger cysts. Solar comedones are not related to acne vulgaris and do not usually become inflamed. They are however very persistent.
6) Nodules are larger and deeper un-inflamed comedones. They more commonly appear on the trunk than on the face.
Comedones are aggravated by a variety of factors, which include:
1) Reduced levels of linoleate, a component of sebum resulting in more scale and reduced barrier function
2) Free fatty acids made from sebum by bacteria
3) Excessive activity of the local hormone 5-testosterone (DHT)
4) Interleukin 1 (IL-1) this is a chemical messenger (cytokine) produced by the cells lining the follicle
5) Rupture of the follicle by injury caused by excessive squeezing of pimples, after abrasive washing, chemical peels or laser resurfacing, or simply from the presence of hard dried-up sebum poking through the wall of the follicle
6) Contact with certain chemicals including isopropyl myristate, propylene glycol and some dyes (which may be found in certain cosmetics)
7) Oil based products such as pomades, sunscreens and petroleum-based moisturizers.
8) Humidity To control comedonal acne choose oil-free cosmetics and wash twice daily with a mild cleanser such as cetaphil gentle cleansing bar for dry/sensitive skin, Dove unscented or Neutrogena cleansing bar and water. Choose 'comedolytic' topical medications. These should be applied once or twice daily as a thin smear to the entire area affected. It may take several months before worthwhile improvement occurs. Treatment needs to be continued long term (sometimes for many years). Antibiotics are not usually very effective for the treatment of comedonal acne.