What Causes Acne?

by | Aug 19, 2020

Acne is the most annoying and common skin disease. Whether it is blackheads, whiteheads, or pustules, it can affect the beauty of the face.

If you want to overcome acne, you can only treat acne in a targeted way by first understanding the cause of acne, and discarding some wrong but deep-rooted concepts.

Dermal layer structure. The dermis contains sebaceous glands, hair follicles, apocrine glands and eccrine glands. The upper part of the dermis is connected to the epidermis, and the lower part is connected to the subcutaneous tissue layer. The sebaceous glands communicate with the hair follicle channels, and the sebum produced by the sebaceous glands flows to the skin surface through the hair follicle channels.

There are sebaceous glands in the hair follicles, which secrete sebum. Normally, sebum will slowly flow out of the pores along the sebaceous ducts, melt into liquid on the skin surface, and form a sebum film. The sebum film prevents the skin from losing water and keeps the skin smooth.

The outermost layer of the skin structure is the epidermal layer. The epidermal layer structure is composed of four layers of skin cells from the basal layer, the spinous layer, the granular layer, and the stratum corneum. The stratum corneum is located in the outermost layer of the skin, and the stratum corneum and the sebum film (A liquid protective layer formed by the oil secreted by the sebaceous glands spread evenly on the skin) protect the skin.

New cells are generated from the basal layer, then migrate to the stratum corneum, and finally shed from the stratum corneum. The normal cycle is 28 days.

The differentiation process of cells. Newborn cells are produced from the stratum basale and gradually migrate upward to the stratum corneum. The migration process takes about 14 days. Keratinocytes and intercellular lipids form the stratum corneum, which is finally shed from the skin. This process takes about 14 days.

For some reason, the keratinocytes at the funnel of the hair follicle stick together and cannot fall off normally. The keratinocytes accumulate more and more at the opening of the hair follicle and eventually cover the pores. This process is called hyperkeratosis.

There is a microorganism called Propionibacterium acnes (P.acnes) in the hair follicle. Its natural enemy is oxygen, so when the pores are covered, the oxygen cannot enter, and Propionibacterium acne begins to multiply.

There are a lot of P. acnes inside the hair follicle, and the body’s immune system quickly starts to work, producing white blood cells to engulf the bacteria, leading to an inflammatory response. A lot of white blood cells and Propionibacterium acnes are fighting in the hair follicles. At this time, we only began to find that we have acne (So you can’t blame eating acne-causing food yesterday. The early work of an acne growth has been prepared for a long time. ).

Normally, the oil secreted by the sebaceous glands runs out along the hair follicles. But when hyperkeratosis at the funnel of the hair follicle. The pores are clogged so that the oil cannot flow out and form whiteheads. A mixture of oil, dead cells and bacteria causes an inflammatory reaction, forming acne.

Depending on the degree of clogged pores and the intensity of the inflammatory response, acne on the face can develop from non-inflammatory whiteheads to papules, pustules, nodules, and even cysts.

We can see that acne needs to meet four conditions at the same time before it breaks out. If one of these four conditions is resolved, the acne will lose the conditions for the outbreak. For example, the problem of clogged hair follicles is solved, no matter how much sebum is secreted, there will be no acne.

1.   Excessive Sebum Production

What causes excess sebum?

  • Your gene sequence determines that sebum production is naturally more than others.
  • Androgen

Androgens are converted into dihydrotestosterone (DHT) in the skin. DHT stimulates the sebaceous glands to secrete large amounts of sebum. So in general, men have more androgens than women, and men have more sebum production than women.

Adolescence, menstruation, pregnancy can lead to the production of androgens.

Polycystic ovary syndrome, adrenal hyperplasia, or adrenal tumors can also cause androgen production.

  • Diet

High sugar foods and high glycemic index foods will cause an increase in insulin-link growth factor-1 (IGF-1). IGF-1 can promote the secretion of sebum and the excessive proliferation of keratinocytes.

Milk contains many hormones, which can cause sebum production . At the same time, milk also increases IGF-1, which leads to sebum production. You can use soy milk or yogurt instead of milk.

  • High temperature. According to research, every increase in ambient temperature by 1°C increases the amount of sebum production by 10%, so the amount of oil produced in summer is more than in winter.
  • Stay up all night and high stress. Many people stay up late, high pressure, when the mood is in tension and anxiety, will stimulate the adrenal glands to secrete more dehydroepiandrosterone (DHEA), thereby promoting the production of sebum.
  • Microorganism. Both Propionibacterium acnes and Malassezia resident in the skin can promote sebum production by sebaceous cells.
  • Ultraviolet rays will stimulate the sebaceous glands to secrete sebum and increase inflammation.
  • Other reasons. For example, using certain cosmetics, taking certain medicines, lacking certain vitamins, constipation, and changing seasons.

In summary, it is too difficult to control the metabolism of the sebaceous glands.

2. Hyperkeratosis At The Opening of The Hair Follicle

As long as the pores are not covered and the living conditions of the anaerobic bacteria in the hair follicles are destroyed, the occurrence of inflammatory skin lesions can be reduced. When the hair follicles remain unobstructed, even if there is more sebum production , it will not cause acne. On the contrary, if the keratinization is not normal, the pores will be easily covered and acne will easily occur.

The main component of adapalene is retinoids, which can regulate the metabolism of keratinocytes at the opening of the hair follicles and restore hyperkeratotic skin to normal skin. Adapalene can also dissolve whiteheads, remove micro-acne, and prevent the formation of micro-acne.

How to use:

Take the appropriate adapalene and apply it to the whiteheads.

Neutrogena’s main ingredient is retinol, which is converted into retinoic acid in the skin, which is retinoids. Neutrogena Wrinkle Repair has a lower concentration than Differin and is less irritating to the skin. This moisturizer can be used on the entire face.

If you have more whiteheads on your face and less red bumps, you can use this moisturizer on your entire face. After long-term use, the whiteheads on the face will be reduced, and the probability of acne will also be reduced.

But if you have more red pimples on your face, this cream is not suitable. At this time, you should first go to a dermatologist to use medicine to treat acne. At the same time, conventional skin care uses skin care products that contain skin barrier repair and anti-inflammatory functions.

3.   Bacteria Overproliferate

The production of acne is caused by the proliferation of anaerobic bacteria represented by Propionibacterium acnes, which stimulates the skin to produce an inflammatory reaction. If we can reduce the number of anaerobic bacteria, we can control the inflammation to a certain extent.

Benzoyl peroxide is highly oxidizing. It can release oxygen and benzoyl, destroying the living conditions of anaerobic bacteria, thereby killing anaerobic bacteria.

Benzoyl peroxide can only be applied to inflammatory acne.

Tea tree essential oil has very powerful functions of sterilization, anti-inflammatory, and anti-infection. 5% concentration can kill 90% of Staphylococcus aureus and E. coli, which is very suitable for acne caused by the imbalance of facial flora.

How to use:

Apply moisturizing cream to the face, then dip a cotton swab into the mixture and apply it directly to acne.

4.   Inflammatory Infection

The red pimples you see on your skin are caused by inflammatory infections. To eliminate pimples, anti-inflammatory is necessary.

Common anti-inflammatory prescription drugs are:

  • Topical antibiotics-clindamycin phosphate gel
  • Oral antibiotics-doxycycline, minocycline

Anti-inflammatory skin care products are added to regular skin care for acne-prone skin.

The best anti-inflammatory skin care product belongs to Phyto-C Superheal Olive Gel. Its main anti-inflammatory ingredient is Olive Leaf Extract. It also adds a variety of amino acids and Zinc Gluconate. It has the functions of anti-inflammatory, repairing, removing red blood, moisturizing, and controlling oil. If it is used in the morning and evening, the red acne scars can be faded in about 3 days, and the skin feel is more suitable for oily skin.

The main ingredients of Skinceuticals Phyto Corrective are patented cucumber extract, olive oil extract, rosemary extract, and the anti-inflammatory effect is weaker than that of Phyto-C Olive Gel. If it is used in the morning and evening, the red acne scars can be faded in about a week, the skin feels a little sticky, and it is more suitable for dry skin.

Cosmetic Olive Serum’s formula is almost an olive gel that replicates the PHYTO-C. Its formula is olive oil extract, various amino acid combinations, zinc gluconate, Centella Asiatica extract, arbutin. However, the olive oil extracts of Phyto-C and SkinCeuticals are patented technologies and ingredients. Cosmetic Olive Serum also has anti-inflammatory, repair, and red blood-staining effects, but its effect is not as good as Phyto-C and SkinCeuticals, and its advantages are relatively cheap and cost-effective.


There are four main factors for acne.

Do not stay up late in life, eat fewer sweets, drink less milk, eat more protein, supplement zinc, supplement vitamins, and maintain a happy mood. A healthy life can reduce the secretion of sebum.

We can also use skin care products or drugs to reduce the probability of abnormal skin keratinization. The pores are not covered, and the probability of acne is reduced.

If you have acne, use some antibacterial and anti-inflammatory products to eliminate acne as soon as possible.

For acne-prone skin, anti-inflammatory skin care products can be added to daily skincare to reduce the probability of inflammation.