Acne – Causes, Symptoms, Diagnosis, Treatment & Prevention

What is acne?

Acne is a skin disease affecting millions of people worldwide. It is one of the most common skin diseases of our time. It affects both sexes. It is more common among young people during puberty, but acne can affect adults as well.

According to a research of US National Library of Medicine and National Institutes of Health, the prevalence of acne among respondents was 82.9%, and was strongly age-dependent with highest rates in the age groups of 13-15 and 16-19 years.[1]

It is believed that acne is caused due to a violation of the hormonal balance of the body, poor nutrition, poor hygiene of the skin, harmful lifestyle habits, toxins accumulated in the body.

For some people, acne disappears after puberty. Very often, a long-term treatment with medications need to be held, as well as skin care with special cosmetics, changes in diet and lifestyle.

Usually, the treatment of acne is difficult, it takes a long time, often requiring changes in the habits of the person affected by acne.

Generally, acne is an unpleasant skin problem that disturbs the confidence of young people, leading to the embarrassment caused by their appearance. In order to avoid permanent scars as a result of acne is necessary to apply adequate and timely treatment.


Puberty is the period of life when, under the influence of hormones, secondary sexual characteristics appear in both sexes.

One of these features is the increased external and internal secretion. As a result of this process, the skin begins to produce more fat, especially in people who are genetically predisposed or have increased functions of the sebaceous glands, which is accompanied by the formation of blackheads and pustules.

For some people, acne is strongly expressed, leaving ugly scars and recesses on the surface of the skin.

Some people have pimples and blackheads only while others – cysts and pustules, depending on the type and severity of their condition. The most severe form of acne is characterized by nodules, painful pustules that can affect the entire face and back.

Cystic Acne
Source: Imgur

Boys are more affected by acne during puberty, which is due to high levels of testosterone.

Testosterone is a hormone that increases the secretion of the skin and hair,  therefore there is a greater percentage of boys with acne than girls during puberty.

In addition to their genetic predisposition, in girls, abnormal hormone levels may be crucial for the emergence of a pimple. As an example, in the normal and regular menstrual cycle for most of the girls, acne symptoms decrease.

Acne is a skin disease in which sebaceous glands are clogged, which leads to the formations of black dots, also known as comedones. They eventually cause redness and pus-filled pimples.

During the process, a severe inflammation may develop, which can bring negative consequences for the acne sufferers.

The secretion, produced by the sebaceous glands, performs many important functions for the body.

It helps to maintain skin elasticity, prevents its excessive drying, participates in thermoregulation, has bactericidal action and others.

When the production of this secretion is heightened, particularly in areas with high concentration of sebaceous glands, such as the face, back, shoulders, it results in acne.

The sebaceous glands activity is regulated by hormonal and nervous vegetative systems of the human body.

During puberty, the level of androgens in the body increases, and it is estimated that they are directly related to increased excretion of secretion from the sebaceous glands.

Teen Acne
Figure 2: Representative facial image of a teen with visible acne.

Estrogens, on the other hand, reduce this secretion. This is why acne treatment can be based on anti-androgen drugs (drugs that block the action of male sex hormones).

The improper production of secretions from the sebaceous glands is known as seborrhea. The reasons for its occurrence can be various.

The most common are hormonal disorders in the functioning of the nervous system, disorders of the metabolism in the body. The skin becomes susceptible to infections, comedones, and acne.

Generally, acne can be divided into 3 types, according to the damage it causes.

The mild type of acne – it is characterized by the occurrence of comedones (blackheads).

Usually, the first manifestation of acne is observed at the beginning of puberty when fat cells “wake up” and their secretion is increased.

What are comedones?

Comedones [2], also known as blackheads/whiteheads are a very common cosmetic problem that affects both dry and oily skin types.

The formation of comedones is due to the increased release of oily secretions and other oxidation processes. The oily secretion fills the expanded of the sebaceous glands, epidermal cells are irritated, forming a mixture of congestion and dead epidermal cells.

Figure 1: Multiple black-colored macules located bilaterally on the cheeks and nose

A comedo can be open (blackhead) or closed by skin (whitehead) [3]].

Being open to the air causes oxidization, which turns it black.

Sometimes the formation of comedones can be caused by the use of cosmetic products. Most often the products (creams and cleansing gels) are not appropriate for the type of skin.

The most typical places where comedones form are the cheeks, forehead, nose, and chin; they can be rarely seen on the arms, chest, back and thighs.

Although comedones can affect both dry and oily skin, they are more likely to appear on the oily skin type. The more fat is produced by the glands, the more likely it is the occurrence of blackheads on the face.

Hormonal changes in the body are the most common reason causing comedones. This is very typical for the period of puberty.

Sebaceous glands are under the direct dependence of the thyroid gland, whose activity is increased in the period of maturation. The contrary is also true – the more the function of the sebaceous glands decreases, the fewer blackheads are formed.

What are some remedies for getting rid of and preventing blackheads?

Read Monika Hristova’s answer to What are some remedies for getting rid of and preventing blackheads? on Quora


Comedones are a cosmetic problem that can be observed with a naked eye. These black spots often appear all over the nose, around the chin and other parts of the face. Comedones can affect other body parts as well.

They do not cause pain, but if scratched, they can easily turn into pimples.

Diagnosing acne

Comedones are easily recognizable. However, a consultation with a dermatologist is recommended in order to determine your skin type, the possible causes for the appearance of blackheads and also the best treatment options for you.

Sometimes the application of inappropriate skin products can make things worse.

Diagnosis of acne is done using series of tests including clinical, psychological and physical indicators.

Severity Scale

The chart below represents the Acne Global Severity Scale:

0 = Normal, clear skin with no evidence of acne vulgaris

1 = Skin is almost clear: rare non-inflammatory lesions present, with rare non-inflamed papules (papules must be resolving and may be hyperpigmented)

2 = Some non-inflammatory lesions are present, with few inflammatory lesions (papules/pustules only; there are no nodulocystic lesions)

3 = Non-inflammatory lesions predominate, with multiple inflammatory lesions evident: several to many comedones and papules/pustules, and there may or may not be one small nodulocystic lesion 4 = Inflammatory lesions are more apparent: many comedones and papules/pustules, there may or may not be a few

4 = Inflammatory lesions are more apparent: many comedones and papules/pustules, there may or may not be a few nodulocystic lesions

5 = Highly inflammatory lesions predominate: variable number of comedones, many papules/pustules nodulocystic lesions are available [4]

Is it bad to pop your pimples?

Popping or squeezing a pimple won’t get you rid of the problem.

Squeezing can even push bacteria and pus deeper into the skin, which might cause more swelling and redness.

Squeezing can also lead to scabs and might leave you with permanent pits or scars.

Acne Types

Acne may vary from a small red dot to a large, pus-filled cysts.

It is possible to manifest itself in many forms, which, in turn, can pass from one to another or be fully independent of origin.

Acne develops as a result of blockage of the follicle with sebum and dead cells, which, afterward, is infected by bacteria.

This causes blockage, redness, and pain in the affected area where the infection develops. Depending on the shape and size, acne can be divided into inflammatory and non-inflammatory.

At the beginning of acne, there is a micro comedo – microscopic lesion. Depending on its growth, it can develop as a black dot – open comedo or white dot – closed comedo. Pustules and knots are a serious form of acne complication.

Pustules are yellowish bumps filled with pus, and the knots are large and thick subcutaneous formations.

There is also an average form of acne, in which there is only redness.

Pus cysts are the most severe form of acne that causes severe pain. These cysts affect the deeper layers of the skin and spread around the primary area of infection.

Acne Types

Acne vulgaris (Acne vulgaris) – is the most common form of acne. There are white and black dots which are simultaneously observed. Acne vulgaris is a skin disease characterized by non-inflammatory comedones and inflammatory papules, pustules and nodules.

The disease is typical for the period of puberty and regresses between 25-30 years of age. Acne vulgaris has a chrono-progressive course with seasonal improvements. Prolonged exposure to strong sun stimulates the autumn worsening of the disease and the passage of inflammatory changes into the deeper layers of the dermis.

The reasons for its development are:

  • Endogenous – autosomal dominant inheritance with variable penetrance of the genes
  • Hormonal
  • Contact irritants – oils, tar, soaps, detergents and others
  • Mental and physical exercise – more often students and athletes

The development of the condition is determined by various factors, but the genetic predisposition is fundamental.

Additional aggravating factors include increased fat secretion, Propionibacterium acnes, and inflammation.
Comedones begin to appear around the adrenal glands in patients with acne (in the T-zone).

This suggests the importance of androgenic hormones in the development of acne vulgaris. Androgen receptors exist in the sebaceous glands, and therefore, individuals with receptor defects do not develop acne.
During adolescence acne vulgaris occurs more often in boys than in girls. During maturity, acne prevails among women.
The pathogenesis of acne vulgaris includes four main mechanisms:

  • Increased sebum secretion – sebaceous glands, hair follicles and apocrine glands are specific targets for androgenic influence. High sebaceous secretion during puberty is due to increased androgen production or increased availability of free hormones.
  • Changes in the composition of skin lipids – patients with acne have high levels of squalene and wax esters and deficiency of linolenic acid. Individual variants of lipid components affect the intensity of follicular hyperkeratosis and the development of bacterial flora in each individual.
  • Follicular hyperkeratosis – due to hyperproliferation, impaired corneocyte separation and changes in the composition of the skin lipids.
  • Bacterial flora – acne is not an infectious disease but is affected by the resident and the transient microbial flora. For the pathogenesis of acne, P.acnes and P.granulosum have the greatest importance, which produce biologically active substances. They pass through the follicular wall and cause aseptic inflammation.

The accumulated corneocytes, sebum and bacteria form microcomedos, closed and open comedones.

Clogged follicles swell and rupture – this deepens the inflammatory process, stimulates leukocyte chemotaxis and connective tissue scarring.
Acne vulgaris may occur in the first few weeks or months of life when the newborn is still under the influence of maternal hormones. This condition spontaneously goes away.
The disease begins with the appearance of a million – white milliar cysts and open comedos.

Subsequently, erythematic millial papules appear, located peripherally, pustules and cysts. Knots are formed around the ruptured sebaceous glands in the dermis.

In severe cases, acne rashes occur with evolutionary polymorphism, scattered on the face, chest, and back. #

Spontaneous remissions are also observed.
In the severe forms of acne vulgaris, affecting the face and body, cysts, fistulas, gigantic comedones and deforming scars and keloids are formed. Superfine pycoccal infection, as well as an allergy to topical medications and foods, may worsen the condition.
Apart from endocrine effects, central nervous system diseases and others, acne eruptions can also be stimulated by:

  • The use of medications – acne medicamentosa
  • Contact with engine oil, tar, floor oil and others – acne professionalis
  • Use of cosmetics – acne cosmetica

Histopathological acne vulgaris is characterized by follicular hyperkeratosis, enlarged and sebum-filled canal, inflammatory infiltrate peripherally and around the sebaceous gland.
Light acne vulgaris form usually heals spontaneously.

The treatment aims to suppress fatty secretion and follicular hyperkeratosis while simultaneously remediating the bacterial infection.

In the beginning, in comedic acne, bactericidal lotions containing salicylic acid, antibiotics, retinoids and others are used. In pustulous acne, the infection is sanitized with astringent alcoholic solutions, gels, antibiotic sprays, and more.

In more severe cases, topical antiseptics and antibiotics are included. Severe refractory to topical cases of acne vulgaris requires the administration of systemic antibiotics that are emitted by sebum – erythromycin, tetracycline, clindamycin, minocycline.
People, affected by this type of acne are advised to do steam baths as well as subsequent cleaning of the face with sodium bicarbonate.

Acne rosacea – this form of acne occurs primarily in adults, more often affecting men. It manifests with red and inflamed bumps on the face, especially on the nose area.

Infantile acne – is a mild form of acne occurring in newborn babies. It is caused by the action of the fetal hormone, sometimes by increased testosterone and follicle-stimulating hormone.

Corticosteroid acne – has a frequent occurrence among athletes because of steroid use. It might grow into an extremely severe condition.

Acne and diet

Poor nutrition, junk food, and too many sweets can cause deterioration of the skin, but cannot be the main cause of acne [6].

These foods increase the level of insulin in the blood, which acts as a male hormone and makes the skin greasy and more prone to pustules development. Fruit and other natural sugars do not affect the appearance of pimples.

Some research papers show that large amounts of milk or dairy products can worsen the condition. This is because dairy foods are high in hormones, so more than three glasses of milk a day is not recommended for people suffering from acne.

This is because dairy foods are high in hormones, so more than three glasses of milk a day is not recommended for people suffering from acne.

A case study of the American Academy of Dermatology concluded that there is a positive association with acne for intake of total milk and skim milk. It hypothesizes that the association with milk may be because of the presence of hormones and bioactive molecules in milk. [5]

How do I get a very healthy skin?

Read Monika Hristova’s answer to How do I get a very healthy skin? on Quora

Treatment of Acne

Treatment of acne is necessary because scars appearing on the skin are very difficult to be removed later.

There is no therapy that could be called “universal”. Treatment depends on the type and the sensitivity of the skin as well as the type of the pimples.

If the condition is caused by a hormonal imbalance, treatment with hormonal medications will be needed as well as an additional treatment of the cutaneous lesions.

Lotions and creams, which have antiseptic and comedolytic effect may be used during such therapies.

Products for acne treatment usually contain salicylic acid, azelaic acid, retinoids or topical antibiotics.

The treatment leads to significant improvement and speeds up the recovery process. Acne sufferers can also improve the effectiveness of treatment with alpha acids peeling therapies, beta acids, salicylic and azelaic acid peeling therapies.

Laser treatments can also be very successful, but the effect is temporary and such procedures usually cost more than the topical treatment options.

When the therapy is complete, regardless of whether it is a laser, peeling or cream, the patient must apply special preparations in order to maintain the improved condition.

The role of these preparations is to control the further work of the sebaceous glands. In more severe forms of acne antibiotic therapy may be administrated.

Laser treatment therapy for both acne and acne scars should be carefully investigated first, as the skin is visibly irritated and bloody scabs may appear afterward.

Treatment of acne scars

Although various methods for acne treatment can significantly reduce the appearance of bumps on the skin, they do not prevent the formation of scars. When scars appear on the skin, there are various procedures aiming to align the texture of the skin and erase unpleasant scars. The most common methods include:

When scars appear on the skin, there are various procedures aiming to align the texture of the skin and erase unpleasant scars. The most common methods include:

Chemical peels with trichloroacetic acid (TCA) – held by an experienced dermatologist;

Laser treatment – appropriate for both treatment of acne and scars removal;

Filling the scars with hyaluronic acid (hyaluronic fillers);

Derma roller – stimulates the production of collagen, elastin and new skin cells (this is one of the most common methods to remove scars on the skin).

Home remedies for acne

Tea Tree Oil 

Tea tree oil [7] is a natural anti-inflammatory and antiseptic. It fights acne without drying the skin. Apply one drop tea tree oil on the affected areas. Tea tree oil is effective for treating stains on the face.

Hamamelis Virginiana (Witch hazel) 

Hamamelis has antibacterial properties, reduces inflammation and cleanses the skin. Its benefits primarily resulting from the high levels of tannin acid that it contains. In its distilled form, witch hazel has long been recommended as an affordable, accessible and effective topical remedy for acne.  The plant [8] is extremely effective in treating chronic acne.

Egg white mask

Egg white facial mask is an easy and cheap way to fight acne. The mask will shrink pores and remove excess oil from the skin. Combine the egg white with oatmeal walnut powder and gently exfoliate. You can also add honey or lemon to rejuvenate the skin.

Green clay 

Thermal properties of green clay [9] are a magical method for treatment of skin diseases and there is no analogical product available on the market. It shrinks pores while providing gentle exfoliation for the sensitive and acne-prone skin. Wash your face thoroughly with an antibacterial soap before applying the green clay mask.

Raw lemon juice 

Lemons [10] help to fight both acne and scars. The acid destroys the bacteria that cause acne. You can apply lemon juice directly to the affected areas on your face, it will kill bacteria and help get rid of the pimples. You can add lemon juice to your favorite mask and exfoliate your face with it. You can also add a few drops of raw lemon juice to your moisturizer and apply on your skin before going to bed.

Lavender oil 

While most oils should be diluted, lavender [11] is one of the few you can apply directly on the skin. It has very strong antifungal and antiseptic properties and softens the skin. Because too much drying of the skin may occur, start with 1 application daily, then gradually increase to 2 to 3 times daily if needed [12].

Protection and hydration

Your daily skin care is essential for the treatment of acne. Keep your skin hydrated. And do not forget sunscreen to protect it from the harmful rays of the sun. Wash your face at least twice daily. hygiene is  Your personal hygiene is crucial to winning the war on acne and achieving the clear skin you deserve. Here are seven tips that go a long way towards that goal, including which skin cleansers to avoid.


  1. The prevalence and risk factors of adolescent acne among schoolchildren in Lithuania: a cross-sectional study
  2. What are comedones?
  3. Blackheads
  4. Acne Global Severity Scale
  5. High school dietary dairy intake and teenage acne
  6. Factors related to patient compliance in the treatment of acne vulgaris
  7. The efficacy of 5% topical tea tree oil gel in mild to moderate acne vulgaris: A randomized, double-blind placebo-controlled study;year=2007;volume=73;issue=1;spage=22;epage=25;aulast=Enshaieh
  8. Antioxidant and potential anti-inflammatory activity of extracts and formulations of white tea, rose, and witch hazel on primary human dermal fibroblast cells
  9. Clay minerals and their beneficial effects upon human health. A review
  10. ANTIBACTERIAL ACTIVITY OF Citrus limon ON Acne Vulgaris (PIMPLES)
  11. Lavender (Lavandula angustifolia Miller)
  12. The antimutagenic activity of Lavandula angustifolia (lavender) essential oil in the bacterial reverse mutation assay

About the author

Monika Hristova

Monika is the Editor-in-Chief at SkinPractice. She is a skin care addict and researcher, who feels strongly about helping people with different dermatology conditions from alopecia to warts.

You can read her recommendations and advice both here at SkinPractice or at Quora where she answers skincare-related questions frequently and is the most viewed author in the Skincare category with more than 3 million views or follow her on LinkedIn.

She is also a certified skin care specialist with certification from the Medical College in Sofia.

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