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September 2001
Tip of the Month
When you read about acne, you find that
the terms sebaceous follicle and hair follicle seem to be used
interchangeably. The observation is correct: sebaceous follicle and hair
follicle are synonymous, but sebaceous follicle is the preferred term.
As the human fetus develops, sebaceous
glands (the glands that produce sebum,
the chemically complex oil that lubricates the skin and coats hair)
develop with hair follicles. When the sebaceous glands are fully
developed, they remain attached to hair follicles by a duct that carries
sebum into the follicle and to the skin surface. Sebaceous glands are
found with hair follicles on all parts of the body except the palms of
the hands and soles of the feet where no hair follicles occur.
The greatest concentration of sebaceous
glands, and the largest glands, are on the face and scalp. While
sebaceous glands occur with follicles that grow coarse scalp and beard
hair, the hairs associated with large sebaceous glands are often so tiny
as to be invisible. Thus, in current medical terminology the total
structure of hair follicle and sebaceous gland is preferentially called
sebaceous follicle.
Fact of the Month
Several pieces of evidence support the
concept that a high level of sebum secretion from sebaceous
follicles is a contributing cause of acne vulgaris (although not the
sole cause; click on Why and How Acne Happens
to learn about the contributing roles of dead follicular cells and
follicular bacteria in comedo
formation and inflammation):
- Acne is rarely if ever seen in
children aged 2 to 6 years when sebaceous glands are minimally
active
- People with acne tend to secrete more
sebum than people without acne
- Medications that reduce sebum
secretion are often effective in treating acne—e.g., retinoic acid
in men and women, estrogen and anti-androgens in women
The role of antibiotics in treating acne
also has a connection with sebum secretion.
P. acnes, the principal
bacterial colonist of sebaceous follicles, metabolizes sebum and
produces free fatty acids as a by-product that may contribute to
inflammation of acne. When the bacterial population of sebaceous
follicles is high, reduction of the population by treatment with
antibiotics is often effective in alleviating acne. Antibiotics are not
indicated in every case; their use must be based on adequate diagnosis
by a dermatologist.
Question of the Month
Each month we pose a question that is
answered the following month. This month’s question:
Can the rate of secretion or the
composition of sebum be altered by diet? If it can, shouldn’t
alteration of diet be considered a treatment for acne?
We’ll have the answer and a discussion
of the answer on AcneNet next month.
Answer to last month’s Question of the
Month
Last month’s question was:
Can the rate of secretion or the
composition of sebum be altered by diet? If it can, shouldn’t
alteration of diet be considered a treatment for acne?
Answer: Diet has never been proven to
have a role in the cause or treatment of acne. Dietary manipulation may
have a role in the treatment of some scaling diseases of the skin, but
not in the treatment of acne.
As discussed in Basic
Facts About Acne, dietary cause is one of the most persistent
myths about acne. Foods, such as chocolate or greasy foods, do not cause
acne, but certain foods seem to make some people’s acne worse. The
following can bring on or worsen it:
- Hereditary factors
- An increase in male hormones found in
both males and females
- Menstruation
- Emotional stress
- Oil and grease from cosmetics, work
environment
No food has been shown to be effective in
preventing or treating acne. A healthy diet is, of course, necessary for
good general health.
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