Acne is a skin disorder characterized by plugged pores or pilosebaceous unit. Pilosebaceous units are made up of sebaceous glands (oil glands) and hair follicles in the dermis or middle layer of the skin. There are lots of oil glands in the body but they are concentrated in the nose and cheek areas. The function of the oil gland is to lubricate and make the skin moist by generating oil or sebum. The sebum then flows through the follicles or tiny tubes that starts beneath the skin and leads to the surface of the skin.
Pores
get plugged due to increased development of keratin (hyperkeratinization)
and increased production of sebum. These plugged pores called "comedo"
often contain dead skin cells, naturally occurring "Propionibacterium
Acnes" bacteria and sebum. P. Acnes bacteria feed on sebum which
means that the higher the sebum content of the oil gland, the greater
is the bacterial population. If the bacterial population is very high
they would cause inflammation and infection of the oil gland which results
in redness and pus. When the population of acne causing bacteria is
low but the pores are blocked, it would simply result in "bumps" at the skin surface.
Types
of Lesions
Mild
to Moderate acne spots:
Whiteheads:
In
this type of lesion the pore is blocked completely which traps sebum,
bacteria and dead skin cells. The blocked pore takes a "whitish"
appearance on the surface. Oftentimes, acne sufferers would want to
pop whiteheads. It is not advisable to pop whiteheads since it may lead
to further complications. The appearance of whiteheads is usually of
short duration compared to blackheads.
Blackheads:
This
type of acne lesion is a result of partially blocked pore. The partial
blockage allows some of the trapped sebum, bacteria and skin cells to
be purged slowly to the surface. As the name implies, they are black
in color which is the reaction of the skin pigment melanin to oxygen
in the air. Blackheads takes a longer time to disappear compared to
whiteheads.
Other
acne lesions include:
Papules:
They
appear as, small ,solid bumps on the skin which is slightly elevated
above the skin surface. Groups of very small papules may be invisible
but they have a "sandpaper feel" when you touch them. Papules
do not contain pus and this is what differentiates them from pustules.
Pustules:
(pimples)
At
the top they are filled with pus and usually they have a red base. They
look similar to a whitehead, the only difference is that pustules are
inflamed appearing like a red circle with a yellowish center when viewed
from the top. They are commonly called as "zits" which is
very tempting to pop.
Severe
Acne have the following lesions:
Nodules:
Basically,
these are pimples which are bigger than 5mm. They are can be painful
and grows as large bumps beneath the skin surface. Scarring is very
common with this type of lesion. These lesions last for several months.
Cysts:
These
are painful sac-like, pus-filled lesions that may cause scarring. It
is similar to a nodule but it is pus-filled and they usually have a
diameter of 5mm or more. Do not squeeze cysts as they may cause scarring.
Macule:
Also
known as pseudo scars because they somewhat look like a scar but unlike
"true scars" they leave no permanent scar or mark. They are
temporary flat, light red or pink spots that have been left from a previously
healed lesion. They may last from several days to a few weeks. Sometimes
they are raised slightly from the surface of the skin.
References
- http://dermnetnz.org/acne/acne-causes.html
"Causes of acne" (Last updated 08 Aug 2007)
- http://www.acneguide.ca/basics/acne/what_causes_acne.html
"What Causes Acne?"(Last modified: Friday, 16-Feb-2007")
- http://www.nlm.nih.gov/medlineplus/acne.html
"Acne" (Topic last reviewed: 13 September 2007)
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last modified: December 07, 2007
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