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What Is Acne?

Acne is a skin condition that occurs due to the overproduction of oil by the oil glands of the skin. The oil that normally lubricates the skin gets trapped in blocked oil ducts and results in what we know as pimples, blackheads, and whiteheads on the surface of skin. Sometimes it also includes deeper skin lesions that are called cysts.

  • Pimples are small skin swellings that sometimes contain pus.
  • Blackheads are dark formations on the skin due to an accumulated mixture of oil and cells in a blocked skin pore.
  • Whiteheads are small flesh-or white-colored bumps due to skin pore blockage.
  • Cysts are closed sacs beneath the skin or deeper that contain fluid or semisolid substances.


The areas of the skin that are most susceptible to acne are those areas that contain the largest number of oil glands. For example, it is estimated that there are 2,000 oil glands per square inch on the forehead alone. The face, chest, shoulders, and back are the areas with the highest population of oil glands.

Acne commonly occurs in people between their teenage years and their 20s. However, it is not restricted to this age. Older adults and children can also have acne.

Facts About Acne

  • In most people, acne will last for about three to four years and in 15% of the cases, acne can continue for eight-12 years.
  • In a smaller percentage (5%), acne will last beyond age 25 and can continue up to age 40.
  • In women particularly, acne may not occur until age 25.
  • In 70% of the cases, women will notice a flare-up in the acne condition prior their menstrual period, perhaps due to an increase of androgens. Androgens are steroid hormones responsible for the development and maintenance of male physical characteristics.
  • The more severe cases of acne tend to occur most often in men, because they produce more of the male hormones that stimulate acne formation.
  • Women with a lot of body or facial hair, and those who have irregular periods, may be at increased risk of acne. These women may want to have their hormone levels evaluated by a physician.

What Causes Acne?

There are four major factors responsible for causing acne. They act together to cause the characteristic pimpleswhiteheads, and blackheads associated with acne. They are:

  • Overactive oil glands
  • Blockage of the skin pores
  • Activity of normal skin bacteria
  • Inflammation

Overactive Oil Glands

Oil glands are located deep in the skin. They are also known as sebaceous glands.

  • Each oil gland is connected to a tiny canal that contains a hair. The canal with its contained hair is called a follicle.
  • The glands produce oil (also known as sebum) that flows to the surface of the skin through these canals to lubricate the hair follicles and the surrounding skin.
  • The opening of the canal with the attached hair (follicle) onto the skin is the skin pore.

The oil glands vary in size, and the larger ones are associated with visible skin pores.

The oil glands are stimulated to produce oil by hormones, specifically the male hormones called androgens (women also have these hormones, but much less of them). These hormones are produced by the testes in men and by the ovaries in women. In both sexes, androgens are also produced by the adrenal glands.

During times of stress, the adrenal glands produce increased levels of these hormones, causing even greater enlargement of the oil glands.

During puberty, the oil glands become overactive in response to hormonal changes.

Blockage Of The Skin Pores

Oily skin occurs when an overactive oil gland enlarges and overproduces oil. Acne develops when some of the pores (through which oil normally flows from the oil gland to reach the skin surface) become blocked, resulting in trapping of oil within the skin pores.

The pores are blocked by skin cells that have been shed from the lining of the skin pore and have bunched together. The cause for this clogging is not known, but it is not due to poor hygiene. A blackhead or whitehead will develop from this skin pore blockage

Activity Of Normal Skin Bacteria

Although acne is not caused by a bacterial infection, bacteria do play a role in making the situation worse. The bacterium Propionibacterium acnes (P. acnes), is a normal part of the skin surface. It keeps the skin from being invaded by harmful bacteria.

When oil is trapped in the hair follicles, the normal skin bacteria P. acnes will grow in the blocked pore. The bacteria produce chemicals that alter the composition of the oil, which makes it more irritating to the skin and causes inflammation.


Inflamed skin is characterized by redness, swelling, warmth and discomfort. Inflammation of the skin occurs because the body’s immune system is acting to rid itself of a foreign substance. In the case of acne, this substance is either bacteria or the irritating compounds they have produced.

These four factors contribute to blocked skin pores, which bulge outward to form:

  • Blackheads. These form when the pores are clogged close to the surface of the skin. Because they are exposed to the skin surface, blackheads don’t usually become inflamed. Blackheads are dark due to the presence of a dark pigment. This color is not the result of dirt in the pores.
  • Whiteheads. These develop from a blockage deeper in a pore. Lacking a drainage path, the oil accumulates in the skin, causing small flesh-colored or white-colored bumps. Unlike blackheads, whiteheads are more likely to lead to the red inflammations known as pimples or zits.
  • Pustules (also known as pimples or zits) occur when the walls of the blocked follicle ruptures. Oil, dead skin cells, and bacteria normally found on the skin surface get into the skin and irritate it, forming small areas of inflammation.
  • Cysts are larger, red, inflamed areas deep in the skin that indicate a more extensive infection.

Who Gets Acne?

Adolescents are the most commonly affected. Because of the high hormonal activity during puberty, acne affects many teenagers. Those individuals whose oil glands produce more oil tend to be affected by acne more often than those whose glands don’t produce excess oil.

Heredity Can Play A Role

Statistics suggest that heredity is a strong contributing factor for acne. A family history of acne means that there probably is a genetic basis for the condition.

Nice To Know:

Does stress cause acne?

Stress can be partially responsible for acne. Hormonal changes are associated with stress, and hormones stimulate the oil glands. People who are anxious may also change their behavior towards their appearance, leading to inappropriate treatment of the acne that can worsen the condition.

Consult your family physician on methods to reduce stress. These may include:

  • Exercise
  • Recreational breaks
  • Good sleeping habits
  • Meditation
  • Laughter
  • Social support network
  • Reduced consumption of stimulants (such as caffeine)

Does a greasy diet make acne worse?

It was long thought that fatty foods, chocolate and sugar aggravated acne. But dietary causes for acne have never been proven scientifically. So although a well-balanced healthy diet that includes plenty of water is recommended for overall good health, no special restrictions on food are imposed for preventing acne.

How Is Acne Treated?

Acne responds well to treatment, especially if treated early, at the onset of the condition.

Treatment is offered to:

  • Prevent possible scarring
  • Deal with inflamed and painful areas
  • Limit the formation of new blackheads and whiteheads
  • Lessen any stress or embarrassment associated with the acne

Mild acne can be treated with over-the-counter medications. More serious acne requires treatment by a dermatologist

Below we consider:

Mild to moderately severe acne

Very severe acne

Side effects of acne treatment

Mild To Moderately Severe Acne

Mild acne is managed well by over-the-counter topical preparations such as:

  • Benzoyl peroxide
  • Resorcinol
  • Salicylic acid
  • Sulfur

Topical creams, gels, and lotions are medications applied directly to the skin. They may contain benzoyl peroxide, antibiotics, or retinoidswhich are vitamin A acids (Retin A).

  • Benzoyl peroxide dries up the oil; it works by killing the bacteria P acnes.
  • Salicylic acid helps stop the shedding of the skin cells lining the oil glands.
  • Rersorcinol and sulfur work by breaking up the pimples.

Most people with mild acne will see results from treatment within several months.

In some people, these medications may initially irritate the face, causing some redness or burning, but this soon settles. However, if it occurs with continued use, the doctor should be seen and other medications considered.

Individuals who have moderately severe acne will benefit from a visit to a primary care physician or a dermatologist. The dermatologist may prescribe topical creams and/or oral antibiotics. Prescription topical medications for acne include:

  • Antibiotic ointments may help reduce inflammation and slow the spread of bacteria
  • Retinoids (Vitamin A derivatives) help to unplug hair follicles; some medications also help to prevent follicles from becoming plugged in the first place. Once follicles are unplugged, other topical medications, such as antibiotics, can enter them more effectively
  • Other prescription-strength topical medications may be used to help control oily skin, reduce inflammation, and stop bacterial growth and spread. Many of these preparations are simply stronger versions of medications available over the counter, including benzoyl peroxide, sulfur, or azelaic acid.

Oral antibiotics. Antibiotics taken by mouth may be prescribed by a physician for moderate to severe acne. The most commonly prescribed oral antibiotics are tetracycline and erythromycin. Antibiotics reduces the population of P. acnes, the skin bacterium responsible for making chemicals that cause inflammation. For this reason, antibiotics will reduce the number of red and yellow pimples.

Need To Know:

Tetracycline can cause permanent discoloration of teeth that are still forming in children. It should not be taken by children who do not yet have all their permanent teeth.

Low-dose contraceptive. In 1992, a low-dose contraceptive,Ortho Tri-Cyclenbecame available for the treatment of moderate acne in women 15 years or older.

  • This contraceptive acts by lowering hormonal activity. This results in reducing the overactivity of the oil glands.
  • Ortho Tri-Cyclen is used in low doses to treat acne, with a combination of synthetic female hormones.
  • In clinical studies, Ortho Tri-Cyclen showed improvement of acne in more than 80% of the participants in the study who were treated with it.

Very Severe Acne

In cases where severe acne does not respond to long-term antibiotic and topical therapy, another oral medication is available. This is called isotretinoin (Accutane®) and is a synthetic derivative (made from chemicals) of vitamin A, which is essential for growth of healthy skin.

  • It is the most effective treatment for severe acne.
  • After four to six months on the treatment, the acne had disappeared in up to 90% of those treated.
  • But the acne may recur in some people, and another course of the treatment may be required.

Accutane® is the most effective acne treatment because it reduces the four major factors that predispose a person to acne:

  • Oil production
  • Blockage of the skin pores
  • The role of the skin bacteria P. acnes
  • Skin inflammation

The course of treatment is four to six months of daily treatment.

Need To Know:

In spite of the high success with Accutaine® in acne treatment, it is only recommended for the most severe cases. This is because it has many side effects and is more expensive than any other treatment.

Side Effects Of Acne Treatment

Topical creams can cause a mild irritation or drying of the skin.

In 95 percent of individuals who take oral antibiotics, there have been no reported side effects. A small percentage of people, however, will experience:

  • Mild abdominal pain
  • Nausea
  • Diarrhea, in rare cases
  • Some women may develop a yeast infection
  • Tetracycline antibiotics, especially doxycycline, sometimes causes sun sensitivity, which means the individual may sunburn more easily

Need To Know:

Should I use Accutaine®?

Accutane can be extremely effective in treating acne. But it is only recommended for severe cases, because it is expensive and does have possible side effects, some of which can be serious. Therefore, one must balance carefully the advantages of its use against the disadvantages of the possible side effects. Fortunately, the side effects do go away once the medication is stopped.

Side effects include:

  • Headaches
  • Chapped lips
  • Drying of the mucous membranes such as the eyes and nose
  • Nose bleeds
  • Joint pains
  • Muscle aches
  • Damage to an unborn baby (if the woman is pregnant)
  • Elevation in the blood lipids cholesterol and triglycerides

Any side effects that you may experience from acne medication should be reported immediately to your physician.

What Will Happen If Acne Is Not Treated?

Mild acne usually resolves over time and may or may not leave some scarring.

When moderate to severe acne is not treated early enough, acne may scar the skin. There are two types of scars that result from acne:

  • Hypertrophic scars are hard upraised areas of the skin surface.
  • Pits, or “pock marks,” are depressed at various depths into the surface of the skin.

Once the scars have formed, there are options for their removal at a later time.

  • Pits are sometimes treated with collagen injections or removed by excision.
  • Dermabrasion, a “scrub brush” type of operation, is used to smooth out pit scars.

These methods are imperfect, however. Prevention with early and appropriate treatment is far more preferable.

Living With Acne

While undergoing treatment for acne, it is important to take precautions in caring for the affected skin.

  • If you are a man who shaves, you should try to avoid nicking your pimples by softening your beard before shaving with soap and warm water. You may also want to try a safety razor and electric razor to decide which is most comfortable. A sharp blade and as little shaving as possible is also recommended.
  • If you are a woman who wears makeup, clean the face carefully every night – with mild soap and water-to remove all traces of makeup. Be especially aware of the appearance or flare-up of acne after using a particular cosmetic, as some cosmetics have been known to aggravate acne. Wash the skin gently with a mild cleanser (ask your doctor to recommend one) in the morning and evening and after exercise. Rinse the skin thoroughly after washing.
  • Shampoo the hair daily, especially if you have oily hair.
  • Using moist warm compresses on the skin may help open blocked pores.
  • Some astringents work well on the pimples for reducing inflammation. They may be recommended for very oily skin, to be placed directly on the oily areas only.
  • In some women taking birth control pills, acne may sometimes gets worse. Tell the physician prescribing the contraceptive about this so that another type of birth control pill can be suggested. Sometimes, however, oral contraceptives can improve the acne condition.
Need To Know:

Popping pimples makes things worse. Avoid picking or squeezing a pimple. Although it might be tempting to do this, it can make things worse by leaving a scar or causing more inflammation.

Sunlight is known to help, but has limits. You may notice that sunlight seems to help reduce acne. This might be true because the UV light in the sun’s rays may reduce the P. acnes bacteria and their by-products that cause the inflammation. But sunlight can also increase the number of whiteheads in some people. Also, overexposure to the sun may increase your risk of skin cancer.

Excessive washing isn’t the answer. Acne cannot be removed by repeatedly washing the skin. Although it is good hygiene to keep the face clean, excessive washing can dry your skin.

What Is The Long-Term Outlook For Acne?

Most people with mild, moderate, or severe acne show improvement within six months with the appropriate treatment. However, if no improvement is observed after three months, then the treatment should be changed.

For example, a common recommendation made by doctors for oral antibiotic treatments are two doses of tablets for six months. But if no improvement is observed after three months of an oral antibiotic regimen, then the doctor may suggest switching to a different antibiotic for the remaining three months.

Frequently Asked Questions: Acne

Here are some frequently asked questions related to acne.

Q: Can I get acne on other parts of my body?

A: The parts of the body most susceptible to acne are the face, the back, and the chest. These are the locations with the highest density of sebaceous glands, the glands responsible for excess oil production. In rare cases, acne can appear on other parts of the body that also have sebaceous glands.

Q: Does acne cause scarring?

A: Yes. When moderate to severe acne is not treated early enough, acne may scar the skin. There are two types of scars that result from acne. Hypertrophic scars, which are hard, upraised areas of the skin surface. Pits, or “pock marks,” are depressed at various depths into the surface of the skin.

Q: Does what I eat cause acne?

A: It was long thought that fatty foods, chocolate, and sugar aggravated acne. But dietary causes for acne have never been proven scientifically. So although a well-balanced healthy diet is recommended for overall good health, no special restrictions on food are imposed for preventing acne.

Q: Can I “catch” acne from someone else?

A: Acne is not an infectious disease, so you cannot “catch” it like you would a cold or the flu.

Q: Will the acne disappear when I get older?

A: Yes, in most people. In a small number of cases, acne that begins in adolescence will last beyond age 25, and can continue up to the age of 40. In women, particularly, acne may not occur until age 25.

Q: How well do over-the-counter medications work?

A: In cases of mild acne, over-the-counter medications successfully manage the disease. The products that are particularly effective are those with 5% or 10% benzoyl peroxide. These medications are available as a cream or a gel and are applied topically to the skin. It is recommended that the benzoyl peroxide be applied not just to the pimples themselves, but also to the entire area affected by the acne. These topical treatments are usually needed for several

Putting It All Together: Acne

Here is a summary of the important facts and information related to acne.

  • Acne is a skin condition caused by overactive oil glands.
  • Acne usually occurs in people during their teen and young adult years.
  • High production of male hormones stimulate overproduction of oil.
  • Skin bacteria can contribute to the problem by reacting with the oil.
  • Whiteheadsblackheads and cysts will occur from pore blockage.
  • Early treatment of acne has a high success rate.
  • Topical creams of benzoyl peroxide, antibiotics, or retinoids are effective treatments for acne.
  • More severe acne cases require oral antibiotics or a synthetic (made from chemicals) vitamin A (essential for growth of healthy skin).

Glossary: Acne

Here are definitions of medical terms related to acne.

Accutane: a synthetic derivative of vitamin A

Acne: a skin disease caused by overactive oil glands

Adrenal glands: two endocrine glands, one located above each kidney, that secrete hormones

Androgens: steroid hormones responsible for the development and maintenance of male physical characteristics

Antibiotics: substances that prevent growth of microorganisms

Astringents: a substance that causes tissue to dry and shrink by reducing its ability to absorb water.

Bacteria: unicellular microorganisms that occupy a wide variety of niches, including the human body

Blackheads: dark formations on the skin due to an accumulated mixture of oil and cells in a blocked skin pore; the pore is clogged close to the surface of the skin

Cholesterol: animal sterol that is present in all tissues of the human body but highly concentrated in the blood, bile, gallstones, and the brain.

Collagen: a fibrous protein present in the human bone, cartilage and connective tissue

Contraceptive: a chemical agent or device that prevents conception or pregnancy.

Cyst: a closed sac beneath the skin or deeper that contains fluid or semisolid substances.

Dermabrasion: a “scrub brush” type of operation to smooth out the scars due to pits

Dermatologists: a physician who specializes in diseases and care of the skin

Endocrine disorders: diseases that affect the secretion by endocrine glands

Endocrine glands: glands in the body, such as the adrenal, that secrete hormones (chemical messengers) directly into the bloodstream

Enzymes: proteins that catalyze chemical reactions without undergoing change themselves

Erythromycin: an antibiotic derived from the bacterium Streptomyces erythreus which is especially effective against gram positive bacteria

Excision: surgical cutting out of the affected area from surrounding healthy tissue

Follicular ducts: microscopic tubules in the skin associated with hair follicles

Heredity: the genetic transmission of characteristics from parents to offspring

Hypertrophic scars: hard upraised areas of the skin surface

Lipids: fats that constitute the principle structural material of living cells

Melanin: a dark pigment found in the skin, retina and hair.

Menstrual period: the monthly discharge of menses or blood in women

Nodules: a small knot like protuberance or node

Ortho tri-cyclen: a low-dose contraceptive

Ovaries: the two female reproductive glands that produce ova or eggs

Papule: another name for a pimple

Pigment: a substance, such as melanin, that produces a characteristic color in skin tissue

Pimple: small skin swellings sometimes containing pus

Pits: depressions on the surface of the skin.

Pock marks: another name for pits

Pore: an opening on the skin that contains a hair follicle

Propionibacterium acnes: a bacterium naturally found on the human skin that protects from infection and chemically alters skin oil

Puberty: stage in the human life when the reproductive organs reach maturity

Pustule: a small skin blister containing pus

Retin A®: the registered trademark for commercially available retinoic acid

Retinoids: Retin-A; Vitamin A acid

Scar: a mark left on the skin after a surface injury or wound has healed

Sebaceous glands: glands that are located beside hair follicles and secrete oil

Steroid: a naturally occurring fat-soluble organic compound present in bile acids, many hormones, some natural drugs, and precursor of certain vitamins

Testes: singular testis – the two male reproductive glands that produce sperm and androgens

Tetracycline: an antibiotic derived from bacteria of the genus Streptomyces

Triglycerides: fatty acids that are the basis for lipids and membrane components

Whiteheads: small flesh-or white-colored bumps due to skin pore blockage; the blockage in the pore is deeper than in a blackhead

Yeast infection-an infection spread by a fungus, often within the vagina

Zit: American slang term for pimple

Additional Sources Of Information: Acne

Here are some reliable sources that can provide more information on acne.

American Academy of Dermatology 
Phone: 888-462-DERM

American Society of Dermatologic Surgery 
Phone: 1-800-441-2737

National Institute of Arthritis and Musculoskeletal and Skin Diseases 
Phone: (301) 495-4484 or (877) 22-NIAMS (toll free)

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