Open comedones are non-inflammatory acne lesions that are open at the skin's surface. They are a dark color in the center as a result of the pore being dilated. This dark, slightly elevated head is the reason that they are also commonly known as blackheads. Blackheads, or open comedones, are relatively harmless and can appear on the face or torso.
A comedo is caused by over-active sebaceous glands. The natural oils that comes from these glands may mix with keratin, or skin debris, and can cause a hair follicle to become clogged. As this accumulation pushes towards the surface of the skin it can become either a closed or open comedo. When it remains open and dilated it is known as an open comedo.
As with most acne problems, there are certain factors that can cause this to happen or make it worse. This can range from improper cleansing of the skin to stress or a hormonal imbalance. Improper cleansing may be something as simple as cleaning too frequently or using the wrong products. Products that are applied to the skin, such as makeup, body lotions and oils, may also contribute to, or exacerbate, problems with open comedones.
People often mistakenly believe that open comedones are a result of excessively dirty skin. This belief stems from the visibly dark coloring at the opening. As a result of being open at the surface of the skin, the debris inside the open comedones are exposed to oxygen. This exposure causes a reaction in the buildup that darkens the surface. When light hits this darkened surface, it reflects off the melanin within causing the center of the opening to appear black.
Scarring is a possibility if this type of comedo is not properly taken care of. One common mistake is attempting to "pop" or squeeze an open comedo. While this may release some of the pus inside, it will not resolve the problem, and scarring may occur as a result.
To prevent open comedones from occurring, it is necessary to adjust habits and products used. Mild soaps should be used to gently wash the skin. Oily products such as makeup, body lotions and hair care products should be discarded in exchange for those that are non-comedogenic or oil-free. Sweat, which is another factor behind acne and comedones, should be kept off of one's body as much as possible. This means removing sweaty clothes or preventing these items from rubbing against one's skin until they can be removed.