Acne is a common skin disease that causes pimples and other abnormalities on the face and upper torso.

  • Acne is caused by an accumulation of dead skin cells, bacteria and sebum that block the hair follicles in the skin.
  • Bumps, such as blackheads, comedones, pimples, cysts, and sometimes abscesses, form on the skin, usually on the face, chest, shoulders or back.
  • To diagnose acne, doctors examine the skin.
  • Common treatments include antibiotics and preparations applied to the skin for mild acne, oral antibiotics for moderate acne and oral isotretinoin for severe acne.

Acne is the most common skin disease in the United States and affects 80% of the population at some stage in life.


Acne arises due to an interaction between hormones, skin oils and bacteria leading to inflammation of the hair follicles (the pores in the skin where the hair grows). Acne is characterized by many types of skin anomalies (lesions). They vary in size and severity, and some penetrate the skin more than others:

  • Carnations (open comedones)
  • White dots (closed comedones)
  • Pimples (inflamed closed comedones)
  • Protruding, solid lumps (papules)
  • Superficial lumps containing pus (pustules)
  • Deeper, firmer lumps containing pus (nodules)
  • Larger bags containing pus (cysts)
  • Sometimes even larger, deeper pus-containing bags (abscesses)

Both cysts and abscesses are pus-filled bags, although the abscesses are larger and deeper.

Abscesses resulting from acne

The sebaceous glands, which secrete an oily substance (sebum), are located in the dermis, the middle layer of the skin. These glands are attached to the hair follicles. Sebum, along with dead skin cells, passes through the sebaceous glands and hair follicles and exits through the pores to the skin’s surface.

Anatomy of the hair follicle

Acne is produced when an accumulation of dry sebum, dead cells and bacteria obstructs hair follicles and blocks the sebum that exits through the pores.

blackhead (open comedo) appears if the block is incomplete.

white dot (closed comedo) appears if the block is complete.

pimple is an inflamed comedone. The hair follicle, blocked and full of sebum, promotes the overgrowth of the Propionibacterium acnes bacteria that are normally found in the hair follicle. This bacteria breaks down sebum into substances irritating to the skin. The resulting inflammation causes skin bumps commonly known as acne pimples. Deeper inflammation causes cysts and sometimes an abscess.



Acne occurs mainly during puberty, when the increase in hormone levels, especially androgens (such as testosterone ), stimulates the sebaceous glands, which produce an excessive amount of sebum. After the age of 20, hormone levels generally decrease enough that acne will subside or disappear. However, up to 40% of women can get acne after reaching the age of 40.

Other diseases that cause hormonal changes that can favor the appearance of acne:

  • Pregnancy or menstruation
  • Polycystic ovary syndrome
  • Certain medications
  • Certain products applied to the skin
  • Very tight clothes
  • High humidity and sweating

Acne can also appear with the menstrual cycle in young women, and can disappear or worsen substantially during pregnancy. The polycystic ovarian syndrome (PCOS) is a hormonal disorder that can disrupt the menstrual cycle and cause or worsen acne. The use of some types of medication, especially corticosteroids and anabolic steroids , can aggravate or cause exacerbations of acne. Certain cosmetics, skin cleansing creams and lotions can aggravate acne by clogging your pores. Very tight clothing and high humidity and perspiration can cause acne.

Because acne varies in severity in most people, sometimes getting worse or better, it is difficult to determine the factors that can trigger an outbreak. Acne is often worse in winter and better in summer, perhaps due to the anti-inflammatory effects of sunlight. There is no relationship, however, between acne and improper cleaning of the face, masturbation, sexual activity or most types of food (for example, chocolate or fatty or spicy foods). It is unclear whether dairy products and high glycemic diets contribute to acne.


Acne usually appears on the face, but it is also common on the neck, shoulders, back and upper chest. The consumption of anabolic steroids usually causes acne to appear on the shoulders and upper back.

Acne has three levels of severity:

  • Mild acne
  • Moderate acne
  • Severe acne

However, even mild acne can be uncomfortable, especially for teenagers, who see a big cosmetic challenge on each spine.

Comparison between mild acne and severe acne

People with mild acne develop only a few (less than 20) blackheads and comedones without inflammation or a moderate number of small, slightly irritated pimples. Pustules, which look like pimples with a yellowish top, can also develop. Carnations appear as small flesh-colored bumps with a dark center. Comedones have a similar appearance, but without the dark center. Pimples cause slight discomfort and have a white core surrounded by a small area of ​​reddish skin.

People with moderate acne have more blackheads, comedones, pimples and pustules.

People with severe acne have a large number of blackheads and comedones, pimples and pustules or cystic (deep) acne. In cystic acne, people have five or more cysts consisting of large, red, painful, pus-filled lumps that can fuse under the skin to form larger, suppurative abscesses.

Mild acne does not usually leave scars. However, squeezing the pimples or trying to puncture them in other ways increases inflammation, the depth of the injury and the possibility of scarring. Severe acne cysts and abscesses often break and, after healing, usually leave scars. The scars can be tiny, deep holes (puncture scars), wider marks of varying depth, or large, irregular fissures. Acne scars last a lifetime and, for some people, are sources of emotional stress. The scars can be dark.

Examples of acne

The acne conglobata is the most severe form of acne, causing severe scarring and other complications of abscesses. Severe acne can appear on the arms, abdomen, buttocks and even the scalp.

The fulminating acne and facial pyoderma (also called fulminating rosacea) are two types of severe acne possibly related and rare that usually appear suddenly.


Doctors base the diagnosis of acne on a skin exam. Doctors look for certain symptoms, such as blackheads or comedones, to determine if the person has acne and not another skin disease, such as rosacea .

After the diagnosis is confirmed, the doctor defines the severity of the acne as mild, moderate or severe, based on the number and type of lesions.


Acne of any severity usually decreases spontaneously after the age of 20, but some people, usually women, can have acne up to the age of 40. Some adults develop mild, occasional and individual acne lesions.

Mild acne usually heals without leaving a mark. Moderate to severe acne heals, but often leaves marks.

Acne can cause a lot of emotional stress for teenagers and cause social distance. Sometimes psychological counseling is needed.


  • For blackheads and comedones, tretinoin cream
  • For mild acne, skin treatment with tretinoin cream, sometimes with benzoyl peroxide or an antibiotic, or both
  • For moderate acne, oral antibiotics in combination with the same skin treatment as for mild acne
  • For severe acne, oral isotretinoin
  • For cystic acne, injected corticosteroids

The general care of acne is very simple. The affected areas should be washed thoroughly with mild soap, once or twice a day. Antibacterial or abrasive soaps, alcohol swabs and constant rubbing do not provide any additional benefit and can further irritate the skin.

Cosmetics must be water-based, as very fatty products make acne worse.

Although there are no restrictions on specific foods (for example, pizza or chocolate), a healthy and balanced diet should be followed (see Nutritional requirements ). The use of a low glycemic index diet and moderation of milk intake may be considered if acne treatment is ineffective in adolescents.

Some acne treatments are useful for certain people. For example, oral contraceptives can be prescribed to women who have acne. This treatment requires more than 6 months to produce results. Spironolactone (a medication that blocks the action of the hormone aldosterone) can also help some women. Several therapies that use light have already helped people who have inflammation (with pimples and pustules).

The treatment of acne depends on the severity of the disease. In the case of mild acne, a simpler treatment is necessary, which implies a lower risk of side effects. The most severe acne, or the one that does not respond to preliminary treatment, needs additional treatment. A treatment plan should always include education, support and the most practical option for the person. People may need to consult a specialist.

Mild acne

The medicines used to treat mild acne are applied to the skin (topical medicines). They work by killing bacteria (antibiotics) or by drying or unclogging pores (comedolytics). Older creams that are sold without a prescription and contain salicylic acid, resorcinol or sulfur work by drying the pimples and causing a slight peeling.

The most common topical medication for pimples and comedones is tretinoin. Tretinoin is very effective, but irritating to the skin, making it more sensitive to sunlight. Therefore, doctors administer this medicine with caution, starting with low concentrations and infrequent applications, which can be gradually increased. People who cannot tolerate tretinoin receive topical treatment with adapalene, azelaic acid, glycolic acid or salicylic acid.

People who also have inflammation (with pimples or pustules) are treated with tretinoin combined with benzoyl peroxide, a topical antibiotic, or both. The two most frequently prescribed topical antibiotics are clindamycin and erythromycin. Topical antibiotics should not be used, except when taken in combination with a retinoid or benzoyl peroxide. Benzoyl peroxide is available with or without a prescription. Glycolic acid can be used in conjunction with tretinoin, or instead.

Blackheads and comedones can be removed (called extraction) by a doctor using sterile needles and instruments called comedone extractors.

Antibiotics taken orally (such as doxycycline, minocycline, tetracycline, erythromycin) can be prescribed to people who have more extensive acne that cannot be treated only with topical medications.

Moderate acne

Moderate acne is usually treated with antibiotics given orally. Typical antibiotics include doxycycline, minocycline, tetracycline, azithromycin, erythromycin and, sometimes, trimethoprim / sulfamethoxazole. Often people use a topical treatment similar to that used for mild acne combined with an oral antibiotic. People may need to take antibiotics for about 12 weeks to achieve maximum benefits.

If possible, oral antibiotics are suspended and topical treatments are used only to maintain control. As acne can reappear after a short period of treatment, it may be necessary to continue therapy for months and even years.

Women who take antibiotics for a long time sometimes develop vaginal yeast infections, which may require treatment.

Women who do not benefit from oral antibiotics may receive oral contraceptives, spironolactone or both.

Severe acne

In the most severe cases of acne, when antibiotics do not work, oral isotretinoin is the best treatment. Isotretinoin, which is similar to the topical drug tretinoin, is the only drug that can possibly cure acne. However, isotretinoin can have serious side effects. Isotretinoin can harm a developing fetus. Therefore, women taking isotretinoin will have to use at least two forms of contraception before, during and after treatment, in order not to become pregnant. Other, less serious side effects may also occur.

Therapy usually continues for 16 to 20 weeks, but sometimes longer.

Doctors prescribe antibiotics by mouth to people with acne conglobata. When antibiotics do not help, doctors prescribe isotretinoin by mouth.

Cystic acne

Sometimes doctors treat people with large, inflamed nodules or abscesses by administering corticosteroids injected into them. In some cases, the doctor makes an incision in the lump or abscess to drain it.

Acne Scars

The treatment of deep acne scars depends on their shape, depth and location.

Small, numerous and superficial scars can be treated with chemical peeling, laser treatments , dermabrasion and / or a newer treatment known as collagen induction therapy (“microneedling”). In collagen induction therapy, a small needle is injected causing changes in the skin’s collagen.

Dermabrasion is a process in which the skin surface is rubbed with an abrasive metal tool to remove the top layer.

Superficial or deep scars can be removed by incision, then joining the two parts of the skin.

The large, cracked scars improve aesthetically with a procedure called subcision, in which small cuts are made under the skin, until the scar tissue is released. This technique often allows the skin to regain its normal contours. In some cases, scars are treated with injections of substances such as collagen, fat or a variety of synthetic materials. These substances can elevate the healed area to make it level with the rest of the skin. Injections of fillers, such as collagen, hyaluronic acid and polymethylmethacrylate, have temporary action and need to be repeated periodically. Some of the other injections are permanent.