What Causes Acne: All You Need To Know

Acne is a common, frustrating skin condition, and not knowing why it’s occurring can be upsetting.

While it can be difficult to find an exact cause, understanding the full range of possible reasons can help you discover what is causing – and what is not causing – your acne.

Have you considered clinical trials for Acne?

We make it easy for you to participate in a clinical trial for Acne, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

What is acne?

Acne is a skin condition that causes pimples, whiteheads, blackheads, and acne cysts.¹ It can occur anywhere on the body, but the most common place where acne appears is on the face.

What generally causes acne?

There are several causes of acne. Read on to find 15 potential reasons why your acne could be occurring.

Clogged pores

The main cause of acne is clogged pores.² Your pores can become blocked by sebum (oil), dead skin cells, bacteria, cosmetics, tight clothing, and facial products. 

Pores are tiny holes in your skin that release oil and sweat to help keep the skin adequately hydrated. When these pores are clogged, they become inflamed, and acne presents. 

Sebum (oil)

As mentioned above, sebum, often referred to as ‘oil’, can clog your pores and enable acne to form.² The sebaceous glands produce sebum near your hair follicles.

If your skin feels very sticky or oily and often looks shiny, this could be a sign that your sebaceous glands are producing too much oil. An overproduction of oil can cause your pores to become clogged and increase your chances of developing acne.

Skin microbiome

Some bacteria in your skin microbiome can contribute to acne.³ When your skin microbiome becomes imbalanced, more acne-causing bacteria can grow.

The main culprit is Cutibacterium acnes.⁴ This acne-causing bacteria can live off the oil produced by your sebaceous glands. The amount of this bacteria can be increased when acne is present, making it a potential cause of the condition.

Hormonal changes

Stress hormones⁵ and hormones present during puberty, pregnancy, and menopause6 can contribute to acne. These life events can lead to hormone imbalances. 

As hormones fluctuate during the menstrual cycle, people who menstruate are more likely to notice an increase in acne during the days just before their period.⁶

Hormones affect acne by increasing the production of oil by the sebaceous glands.⁶


In humid conditions, less moisture evaporates from your skin. This can lead to more oil and moisture clogging your pores, resulting in acne.⁷

Additionally, hot temperatures without humidity may also contribute to acne.⁷

Exercise and physical activity

During exercise, the excess moisture from sweat can clog your pores and make your skin more prone to acne.

Sports equipment and clothing that causes friction or traps sweat against your face or acne-prone areas can also cause clogged pores.⁸


Experts claim that stress is not directly linked to acne.⁵ However, stress may affect your hormone levels and can make your acne worse.

Masks and face coverings

Masks and face coverings can enable pores to become clogged by trapping excess moisture and oil.⁹

However, you do not need to ditch your mask to avoid acne. Instead:

  • Limit the amount of makeup you wear underneath it

  • Switch masks during the day

  • Find one that fits comfortably

  • Take short breaks from wearing one during the day

Wrong cleansing methods

Skincare professionals recommend that you wash your face gently, twice daily.¹ They also suggest washing your face after physical activity or exercise.

However, excessive washing can make the skin dry, and to counteract this problem, your skin will produce more oil. Exfoliating too often or using cleansers not suited to acne problems can also dry out your face too much.

On the other hand, if you forget to wash your face, excess oil and dead skin cells can accumulate and clog your pores. 

Aspects of your diet

Some researchers claim that following a low-glycemic (low-glucose) diet can prevent acne.¹⁰ This suggests that diets high in glucose could contribute to the development of acne. 

However, other evidence suggests that fatty foods and dairy products can worsen acne.¹⁰ 

Researchers don’t yet have strong evidence linking dietary changes to acne, and more studies are needed in this area. It is thought that certain diets could affect hormone imbalances. 

If you notice that you are more prone to acne breakouts after consuming certain foods, taking a break from them may determine whether or not they are an actual cause of your acne. 

Oil from your hair

If you notice acne near your scalp, this could be due to oil from your hair.¹¹ This oil can also spread to your face and clog your pores. 

Cosmetics and hair products

Acne related to your cosmetics often appears on your cheeks, chin, and forehead.¹² Cosmetics and hair products can clog your pores and cause acne. 

Additionally, reusing the same foundation brushes and sponges without washing them between each use can transfer acne-causing bacteria back onto your face.¹²

Wearing thick, heavy cosmetics can also make you more prone to acne, especially if you wear a lot of makeup underneath a mask or face covering. 

Certain medications

Some medications¹³ such as birth control6 and steroids have side effects linked to acne. However, although acne is a potential side effect of certain medications, it does not necessarily mean that they will definitely cause acne. 

If you think that your medications could be contributing to your acne, talk to your doctor before making any decisions. 


People who smoke are more likely than non-smokers to develop acne.⁵ Researchers also found that people who smoked more often were more likely to develop severe acne problems.

Endocrine disorders such as polycystic ovary syndrome

People who suffer from polycystic ovary syndrome also tend to have severe acne.¹⁴

Polycystic ovary syndrome is a disease that can cause hormonal imbalances. It is these hormonal imbalances that can lead to acne.

What causes acne in adults?

Acne is a common problem for adults; it can even affect people in their 50s.⁶ Some people develop acne for the first time during adulthood.

Adult acne is caused by many of the reasons mentioned above but is most commonly associated with:

  • Hormone fluctuations during menstruation, pregnancy, and menopause 

  • Stress 

  • Skin and hair products 

  • Medications 

  • Underlying medical conditions

How is acne diagnosed?

Acne is diagnosed visually, with no additional tests usually required for a diagnosis.¹⁵ A doctor or skin care specialist can diagnose your acne and determine which type you have.

Once you know which kind of acne you have, you can find the best treatment for it.

Are there other conditions that might be mistaken for acne?

Several other skin conditions can resemble acne.


Rosacea is an inflammatory skin disease that commonly affects the central areas of the face.¹⁶ It is most common in people aged 30–60 years. Rosacea can look similar to acne in that red spots can appear, which may become larger pimples or blemishes.

The main difference between rosacea and acne is the amount of redness. Rosacea presents as large red patches on the face. In acne, redness is only seen around the spots or scars. 

The persistent redness with rosacea occurs due to erythema — inflamed and damaged blood vessels. The spots that appear on the face are caused by skin irritation linked to the condition.


Folliculitis is a skin condition that occurs when the hair follicles become inflamed.¹⁷ It can be mistaken for acne because the small red bumps look similar.

The main difference between folliculitis and acne is that folliculitis can occur anywhere on the body, whereas acne is mainly on the face and upper body. Folliculitis may also present with a burning and itchy feeling. However, this can also sometimes be a symptom of severe acne that is inflamed.

Folliculitis caused by a bacterial infection is commonly linked to Staphylococcus aureus (staph). Staph is not the same as acne-causing bacteria, but it is also a part of your skin’s microbiome.

Folliculitis can also be caused by hair follicle irritation, such as from shaving with a razor.

Sebaceous hyperplasia

Sebaceous hyperplasia is a skin condition that commonly affects middle-aged or immunocompromised people.¹⁸ However, any age group can experience this condition. 

Sebaceous hyperplasia occurs when the sebaceous glands become enlarged with entrapped sebum. They can look like small yellow or flesh-colored shiny bumps, and it is considered a benign condition, and no treatment is required. 

The main difference between sebaceous hyperplasia and acne is that in sebaceous hyperplasia you will see an indented or pitted area in the center of the small bump with possibly a small blood vessel inside. In contrast, an acne bump will usually be raised without prominent blood vessels.

Can acne breakouts be prevented?

Acne breakouts can be minimized but can never be entirely prevented. Therefore, treatments or precautions aim to reduce the amount of recurring acne.

Although a complete cure for acne would be most welcome, it is impossible to avoid every possible element that causes an outbreak to occur.

What doesn’t cause acne?

Many myths circulate about the cause of acne. Read on to bust these myths.

Acne is not age-related 

Many people assume that acne is related to a person’s age. While it appears that teenagers are more affected by acne, it is not strictly linked to age.¹⁹

As mentioned previously, acne can first develop for some people during adulthood, and people who are in their 50s can still have acne. 

Acne has also been known to affect infants and children.²⁰ Essentially, anyone can experience acne regardless of their age. 

Acne is not caused by dirt

Contrary to what some people believe, dirt does not cause acne, and in some cases being too clean can actually cause acne.¹⁹ Frequent washing and harsh scrubbing can dry out the skin and encourage it to produce more oil. The excess oil then clogs your pores.

Sunscreen should not be avoided

Some believe that sunscreen is the cause of their acne, and they could be right if their sunscreen is oil-based.²¹ However, using sunscreen is essential because it can prevent skin damage and irritation.

If the skin is damaged or irritated, it will be harder for existing acne to heal, making the issue more problematic.

Oil-free sunscreens can overcome this problem and should be used by people with acne. 

Unhealthy food does not always cause acne

It is a common misconception that unhealthy foods such as chocolate or fatty foods directly cause acne.²¹

As mentioned previously, some foods may trigger acne; however, this is not true in all cases. 

If you notice that certain foods are related to your acne, you may wish to avoid them. However, if you see no difference after cutting those foods out, there is no point in avoiding them.

Acne does not only affect people with oily skin

Another misconception is that only people who have an oily skin type are affected by acne.²² However, many other causes of acne are not linked to oily skin, such as hormonal changes or lifestyle factors.

Not all cosmetics cause acne

Some people think that all cosmetics cause acne because these products clog the pores.²² However, switching to oil-free and lightweight cosmetics can be enough in some cases to reduce the recurrence of acne.

When to see a doctor for acne

If your acne makes you feel depressed, less confident, or you avoid social occasions because of it, you should discuss this with your doctor.

In some cases, acne can become infected and will require treatment. If your acne becomes severe, inflamed, red, and painful, seek a doctor’s advice immediately.

The lowdown

There are many common causes of acne, and being aware of these may enable you to eliminate some of the triggers for your acne. While a complete cure is not possible, you can reduce the recurrence of acne by taking appropriate preventative methods.

If you are concerned about your acne, it is best to discuss this with a doctor so they can give you advice about the best treatment.

  1. Acne: Overview | American Academy of Dermatology Association (AAD)

  2. Acne vulgaris | National Center for Biotechnology Information (NCBI)

  3. Acne, the skin microbiome, and antibiotic treatment (2019)

  4. Cutibacterium acnes (Propionibacterium acnes) and acne vulgaris: a brief look at the latest updates (2018)

  5. Acne: Who gets and causes | American Academy of Dermatology Association (AAD)

  6. Adult Acne | American Academy of Dermatology Association (AAD)

  7. Seasonal aggravation of acne in summers and the effect of temperature and humidity in a study in a tropical setting (2018)

  8. Is sports equipment causing your acne? | American Academy of Dermatology Association (AAD)

  9. 9 ways to prevent face mask skin problems | American Academy of Dermatology Association (AAD)

  10. Can the right diet get rid of acne? | American Academy of Dermatology Association (AAD)

  11. What to know about scalp acne | WebMD

  12. I have acne! Is it okay to wear makeup? | American Academy of Dermatology Association (AAD)

  13. Medications that can cause acne | WebMD

  14. Is that stubborn acne really acne? | American Academy of Dermatology Association (AAD)

  15. Acne: diagnosis and treatment | American Academy of Dermatology Association (AAD)

  16. Rosacea | The New England Journal of Medicine (NEJM)

  17. Folliculitis | Mayo Clinic

  18. Sebaceous hyperplasia (2021)

  19. Common myths about acne | Atrium Health Wake Forest Baptist

  20. Is that acne on my baby’s face? | American Academy of Dermatology Association (AAD)

  21. 10 myths and facts about adult acne | WebMD

  22. The top 12 acne myths and why they aren’t true | Anne Arundel Dermatology

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