What Is Acne?...continued
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.
People with acne frequently have a
variety of lesions, some of which are shown in the diagrams
below. 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. 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. Both whiteheads and blackheads may stay in
the skin for a long time.
Other troublesome acne lesions can
develop, including the following:
inflamed lesions that usually appear as small, pink
bumps on the skin and can be tender to the touch
– papules topped by white or yellow pus-filled lesions
that may be red at the base
Nodules – large,
painful, solid lesions that are lodged deep within the
Cysts – deep,
painful, pus-filled lesions that can cause scarring.
Part 1: What is acne?
Part 2: What is acne? ...continued
Part 3: What causes acne?
Part 4: How is acne treated?
Part 5: How should I care for my skin?
Part 6: Current research for acne?
Source: Adapted from National
Institute of Arthritis and Musculoskeletal and Skin Diseases