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What is Acne?

Acne (also known as pimples) is a common condition of the skin in which pores on the face, neck, chest or back become plugged and the surrounding skin becomes red and inflamed. There are different types of acne, including blackheads and whiteheads (also called comedones). In severe cases, red bumps called pustules or cysts can also develop.


Many people experience acne during their teenage years due to the changes that occur during puberty. Hormone changes lead to an increase in the production of sebum by the sebaceous glands.


Although acne is rare in children, acne and acneiform (acne-like) lesions can occur in infants. A young infant may have an acne eruption around the nose or cheeks. This is usually caused by hormonal changes that occurred as the baby was developing, and the eruption typically clears in a few weeks without acne medicine treatment. Infantile acne usually appears as rash-like comedones and papules on the face.

The following is a picture of a young infant with acne:

Acne baby image

There are various factors that may lead to worsening of acne, including medications, cosmetics and underlying medical conditions. Fortunately, there are many effective remedy treatments for acne.


Acne affects at least 85% of the population at some time during their lives. In its various forms of severity, acne is so common that it is sometimes considered a normal process of development. People aged 15 to 25 years are most likely to suffer from acne.


Approximately 95-100% of males and 83-85% of girls aged 16-17 years suffer from acne. The periods between 14 and 17 years of age in girls, and 16 and 19 years of age in boys, are the most severe stages of acne.


Although acne usually clears up by early adulthood, some people may experience this problem for the first time when they reach middle age. During the adult years, around 10-20% of adults may continue to experience some degree of acne. However, after adolescence the rates of acne decline with age.

Risk Factors

What causes acne?

There are many misconceptions about what causes acne. It is not caused by having dirty skin or by eating the wrong types of foods. Actually, it is caused by the actions of the body’s hormones, which stimulate glands in the skin to produce more oil. Pores in the skin become plugged with an overabundance of normal skin cells known as keratinocytes. These cells join a fatty substance called sebum to create a plug in the follicle. The increase in fatty sebum provides an environment which encourages overgrowth of Propionobacterium acnes, a normal bacteria that lives on the skin. Bacteria growing in the blocked pores can lead to redness, swelling, and pus-filled bumps. This produces the skin lesion commonly known as pimples.


Hormonal changes in the adolescent body, affect the glands and the chemical substances they produce. During adolescence, the sebaceous glands that produce sebum are enlarged. This is due to the action of androgens.

Hormonal influences

In most people with acne, the amount of androgen hormones circulating in the bloodstream is normal, but the androgens have a profound effect because the sebaceous glands are highly sensitive to them.

In rarer cases, the amount of androgens is excessive due to a disorder such as polycystic ovarian syndrome (PCOS). This is a disorder in women that may cause acne. PCOS is characterized by an irregular menstrual cycle, hirsutism, acne, ovarian cysts, bodily resistance to the normal effects of insulin, and the development of dark velvety skin, usually in the neck and armpits, known as acanthosis nigricans.


As well as hormonal changes, acne can also be caused by medications and other substances that come in contact with the skin. Medications that can contribute to the formation of acne lesions include:

  • Androgens;
  • Azathioprine;
  • Barbiturates;
  • Bromides;
  • Corticosteroids;
  • Cyclosporin;
  • Isoniazid;
  • Lithium;
  • Phenytoin.

Physical factors

Oil-based cosmetics can enhance the growing environment for acne-producing bacteria. Certain hair dyes and products for the skin can make existing skin lesions worse. Excessive moisture, from humid air or perspiration, can also worsen acne lesions. Excess scrubbing of acne can aggravate the condition by promoting inflammation. Rubbing from helmets, shoulder pads, turtlenecks, and bra straps can trigger or worsen acne.


Acne tends to resolve when we reach the later adult years, as androgen levels decline. However, it may persist into adult life, or develop for the first time in adulthood. About twelve percent of women and five percent of men at the age of 25 still have acne. Adolescent acne predominantly affects men, in contrast to acne developing in later adult life, which predominantly affects women.


When you visit the doctor, he or she may ask the following questions, as they see necessary:

  • Are there any local symptoms such as pain or tenderness?
  • Are there any symptoms of infection such as pus, skin redness, fever, etc?
  • Are there any other systemic symptoms (e.g. in polycystic ovarian syndrome, are there changes in the menstrual cycle (periods), problems with falling pregnant, etc)?
  • Where are the acne lesions predominantly located?
  • Have there been any new medications, cosmetics or chemical applications applied to the skin?
  • Are there any other things that make the acne worse?
  • How have the acne lesions affected you mentally/emotionally?
  • Have there been any prior treatments for acne?

Clinical Examination

When your doctor examines you, he or she may look for the following features:

  • The distribution of acne lesions is commonly in the oily areas of the face, neck, chest and back. Closed comedones occur when sebum accumulates beneath a thin layer of superficial skin, but there is little inflammation. Open comedones occur when the follicle is spread open by a core of keratinocytes (skin cells) that appear dark due to oxidation.
  • In patients with polycystic ovarian syndrome, there may be increased facial and body hair, and dark velvety skin in the armpits and neck.

How is it Diagnosed

The doctor will usually be able to make a diagnosis of acne based on what is present clinically. However, in certain circumstances, they may suspect an underlying medical conditions (e.g. PCOS), and total testosterone and other hormonal levels may be measured. Skin swabs may be taken to rule out infection if there is no response to treatment, or if improvement is not maintained.


Most cases of acne will clear up without leaving any scars or other signs. However, in more severe cases, some manifestations of the disease can last forever. Severe acne can leave scarring in the form of pits or indentations in the skin.

Local inflammatory processes can be followed by changes in skin colour, resulting in a permanent darker reddish or brownish shade at the site of healed acne lesions. This is most common in patients with darker skin.


Reasons for treatment

Despite acne being very common, it is still very important to treat it effectively. Acne can be aesthetically and sometimes physically unpleasant. It may cause you pain, recurrent bleeding or discharge. In adolescents it can cause psychological distress and sometimes social problems due to poor self-esteem. Scarring is possible in the long-term, which may cause psychic distress. With early intervention and treatment, however, much of this scarring can be prevented.

Aims of treatment

The main goal of treating acne is to eliminate comedone lesions. This is achieved by normalising skin cell shedding, decreasing the activity of the sebaceous glands, and decreasing the amount of bacteria and inflammation in the skin.

There are both local and systemic medications which can help treat acne. In mild cases, localised therapy applied to the skin should be sufficient.

General measures

Skin affected by acne may be washed several times a day with soap and water. Holding a hot wet flannel on the face, followed by gentle rubbing with a plain soap, may be more effective. Vigorous scrubbing or squeezing of acne should be avoided because it may rupture the comedones and aggravate acne lesions. If dry skin is also a problem, a light moisturiser may help.

While most non-oily cosmetics are relatively safe, excessive makeup should be avoided and removed at bedtime.

Mild acne may benefit from over-the-counter soaps and washes. Check the label to see if the soap or wash contains any ingredients helpful in getting rid of acne (e.g. benzoyl peroxide, salicylic acid, or sulfur).

Specific measures

If you have more severe acne, your doctor may prescribe you a special soap, wash, gel or cream to apply to the skin. These treatments can contain an antibiotic (e.g. clindamycin or erythromycin), azelaic acid, benzoyl peroxide, sodium sulfacetamide, or sulfur.

Medications derived from vitamin A, called retinoids, are prescribed to target blackheads and whiteheads. The most commonly used retinoid is tretinoin.

Ultraviolet light therapy is less effective than natural sunlight, but is helpful for extensive acne. It can be a helpful additional treatment in the winter months.

Local agents

Acne medications that have to be applied to the skin are generally used once or twice a day. It may take a period of several weeks before any improvement is seen. During treatment with some medications, your skin can become very dry and scaly.

Agents applied to the skin to help treat acne include retinoic acid, benzoyl peroxide and salicyclic acid. These medications work by changing the way the skin is shed from the body surface, helping prevent the precursor acne lesions.

Topical antibacterial agents (e.g. azelaic acid, erythromycin or clindamycin) may also be helpful treatments in some situations.

Systemic agents

If you have more severe acne, your doctor may choose to prescribe pills to use with or without a cream or lotion. Acne medications taken by mouth include the antibiotics tetracycline and doxycycline. Other oral antibiotics that are used less commonly for acne include clindamycin, erythromycin and sulfonamides. Medications taken by mouth may cause problems such as stomach upset, dizziness, skin redness after sun exposure, and infections.

In some people, birth control pills, as well as drugs that affect androgen levels, may be beneficial.

Isotretinoin is only given to people with severe acne that is not responsive to any other treatment and cannot be treated any other way. This drug can cause serious problems, including birth defects, and people who take it must avoid becoming pregnant.


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  3. Goodman GJ. Acne and acne scarring: Why should we treat? Med J Aust. 1999;171(2):62-3. [Full text]
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Posted On: 19 August, 2006
Modified On: 3 February, 2011
Reviewed On: 29 September, 2007


Created by: myVMC