Here is a copy of a patient handout from the American Academy of Family Practice web site
What is acne?
Acne happens when the inside of a hair follicle becomes sticky and forms a plug. Every strand of hair grows from a follicle under your skin.
Oil glands in your skin keep making a greasy substance called sebum (say: see-bum). This sebum gets stuck behind the plug in the hair follicle. Bacteria get inside your hair follicle or oil gland and cause swelling, redness, and pus. Finally, a bump forms on your skin.
Acne is most common on the face, neck, back, and arms. There are three kinds of acne: mild, moderate, and severe.
Why do I have acne?
Almost everyone has acne at some time in life. People who have bad acne often have family members with the same problem. Acne is not caused by greasy foods or poor hygiene.
What kind of acne do I have?
Your acne is mild if you have only whiteheads (white bumps) and blackheads (dark specks) in your skin.
You have moderate acne if you have swelling, red bumps, or pustules, along with the whiteheads and blackheads. A pustule is a large red bump with a white head.
Your acne is severe if you have deep, painful bumps under your skin in addition to the whiteheads and blackheads.
How is acne treated?
The purpose of most acne medicines is to stop plugs from forming in hair follicles and to reduce swelling in your skin. Acne is treated with topical and oral medicines. Your doctor will tell you what kind of medicine is right for your acne.
You put topical medicines on the areas where you have acne. You can buy some of these medicines at a drug store without a prescription from your doctor. If you have mild acne, many of these medicines may help you.
Oral acne medicines come in pill or capsule form. Your doctor must prescribe these medicines. If you have severe acne, you might need to take an oral medicine called isotretinoin (say: i-so-tret-in-oyn).
You also need a doctor's prescription to buy some topical acne medicines. These medicines include topical retinoids and antibiotics. Retinoids work by loosening plugs or stopping plugs from forming. Antibiotics decrease redness and swelling, and they attack the germs that make acne worse.
Some topical acne medicines may irritate your skin, especially in the first few weeks that you use them. Mild moisturizing lotions and soaps (such as Cetaphil Cleanser, Dove, or Purpose) can help stop the irritation.
Washing your face more than twice a day can increase redness and discomfort. Picking at acne can worsen redness and cause scars.
What can I expect from acne treatment?
There is no cure for acne-but your acne can be controlled. Most acne medicines take eight to 12 weeks to work. The best results happen after taking medicine for three months.
Sometimes, acne may seem to get worse in the first few weeks of treatment, because hidden bumps rise to the skin surface. Your acne will get better if you keep using the acne medicine.
When you start using a new acne medicine, you may have mild redness and swelling of your skin. Call your doctor if the redness and swelling continue or become worse.
This handout provides a general overview on this topic and may not apply to everyone. To find out if this handout applies to you and to get more information on this subject, talk to your family doctor.