What Causes Acne?

The exact cause of acne is unknown, but doctors believe it results from
several related factors. One important factor is rising hormone levels. These
hormones, called androgens (male sex hormones), increase in both boys and
girls during puberty and can cause the sebaceous glands to enlarge and
make more sebum. Another factor is heredity or genetics. Researchers
believe that the tendency to develop acne can be inherited from parents. For
example, studies have shown that many school-age boys with acne have a
family history of the disorder.



Factors That Can Contribute to Acne or Make It Worse

Several factors can contribute to the cause of acne or make it worse.
Changing hormone levels in girls and women may cause a flare in their acne
2 to 7 days before their menstrual period starts. Hormonal changes related to
pregnancy or starting or stopping birth control pills can also cause acne.
Stress, particularly severe or prolonged emotional tension, may aggravate
the disorder.
In addition, certain drugs, including androgens, lithium, and barbiturates,
are known to cause acne. Greasy cosmetics may alter the cells of the follicles
and make them stick together. Friction caused by leaning on or rubbing the
skin or the pressure from bike helmets, backpacks, or tight collars can
contribute to or worsen acne. Also, environmental irritants (such as pollution
and high humidity), squeezing or picking at blemishes, and hard scrubbing
of the skin can make acne worse.
Myths about the Causes of Acne

There are many myths about what causes acne. Chocolate and greasy foods
are often blamed, but research has shown that foods seem to have little effect
on the development and course of acne in most people. Another common
myth is that dirty skin causes acne; however, blackheads and other acne
lesions are not caused by dirt.