Acne Science

Acne Science

Acne is a complex disease. The Acne Science section covers a range of scientific topics related to the development of acne and the available treatments. For more discussions about common acne questions, refer to our Frequently Asked Acne Questions page.

What Causes Acne?

Inflammatory Acne Papules Skin and Cellular View
Inflammatory Acne Papules Skin and Cellular View

Acne is a complex disease and many factors can contribute to the development of acne symptoms. Every case of acne is unique and the blend of factors that cause acne varies between individuals. This section contains a list and discussion about the factors that are major contributors to the development of acne symptoms.

Acne at a Cellular Level

Whitehead Pimple Skin and Cellular View
Whitehead Pimple Skin and Cellular View

Most people can recognize acne when it presents on the face or body. Most people also have the vague understanding that acne is associated with oily skin and an excess production of sebum. But beyond that, few people really grasp what is actually happening at the microscopic level of a pimple. This section discusses the formation of acne lesions at a microscopic level.

The Sebaceous Glands

Hair Follicle, Sebaceous Glands and Sebum (Wikipedia)
Hair Follicle and Sebaceous Glands (Wikipedia)

Sebaceous glands produce and secrete sebum, which is responsible for moisturizing and protecting skin and hair. Sebaceous glands are essential components of healthy skin. Damaged or malfunctioning sebaceous glands contribute to many dermatological conditions, including acne vulgaris. This section discusses the structure and function of the sebaceous glands.

Sebum

Composition of Human Sebum
Composition of Human Sebum

Sebum is a naturally occurring substance that moisturizes, lubricates and protects the skin and hair. Sebum is produced by the sebaceous glands of mammals. Healthy sebum production is essential for the integrity and normal function of the skin as a protective organ. Sebum is also an important source of energy (food) for acne-causing Propionibacterium acnes bacteria. This section discusses the biology of sebum and its role in the development of acne symptoms.

What is Propionibacterium acnes?

Propionibacterium acnes (Toyoda, et al)
Propionibacterium acnes (Toyoda, et al)

Propionibacterium acnes (P.acnes) is a bacteria that can colonize the the skin and hair follicles. Excessive growth of this bacteria in the skin contributes to acne vulgaris. Propionibacterium acnes (P. acnes) is a bacteria that grows deep inside of pores, where it feeds on the sebum that is produced by the sebaceous glands that surround the base of the hair shaft. Most individuals with acne symptoms have an overgrowth of P. acnes bacteria in their skin. Several research studies have indicated that specific strains of P. acnes bacteria are commonly associated with acne vulgaris. This section details what P. acnes bacteria are and how it contributes to acne symptoms.

The Antibiotic Susceptibility of Propionibacterium acnes

Bacteria Antibiotic Susceptibility Test Plate (credit - Wikipedia)
Bacteria Antibiotic Susceptibility Test Plate (Wikipedia)

Propionibacterium acnes is a bacteria that grows within hair follicles and contributes to acne symptoms. Antibiotics reduce the growth of acne-causing bacteria and are a common treatment for acne symptoms. For the past 50 years, physicians and researchers have been screening the susceptibility of Propionibacterium acnes (P. acnes) bacteria to different antibiotics. The results from these studies clearly demonstrate that in many places, P. acnes bacteria are becoming increasingly resistant to certain classes of antibiotics. This section discusses the results of research studies about the antibiotic sensitivity of P. acnes bacteria.

The Antibiotic Families

Tetracycline Antibiotic Capsules
Tetracycline Antibiotic Capsules

There are many different families of antibiotics. Each antibiotic family targets bacteria in a unique way. Each antibiotic family tends to be more effective against certain types of bacteria, and less effective against others. Antibiotics from several different families are used for the treatment of acne. Antibiotics can be used applied topically or ingested orally. The route of delivery, the ability of an antibiotic to accumulate in the skin and the susceptibility of P. acnes bacteria to an antibiotic all impact the efficacy of a given antibiotic treatment. This section discusses the different classes of antibiotics that are used in the treatment of acne.

How Do Bacteria Become Resistant to Antibiotics?

Bacteria Cell (Wikipedia)
Bacteria Cell (Wikipedia)

Bacteria can become resistant to antibiotics that they were susceptible to in the past. There are several factors which contribute to the growing problem of antibiotic-resistant bacteria. This section discusses the many ways that antibiotic resistance may occur, as well as the conditions and environments that promote the development of antibiotic-resistant bacteria.

The Antibacterial Activity of Essential Oil

Eucalyptus Essential Oil Vials
Eucalyptus Essential Oil Vials

Many essential oils and other plant extracts have antimicrobial properties which can be helpful for health and wellness applications. There is an incredible diversity of essential oils and other plant extracts available on the market today. This selection provides a plethora of options for both professional and casual practitioners of Naturopathic remedies for many health issues, including acne. This section discusses the scientific research into the antibacterial properties of plant essential oils.

Avoiding Negative Interactions Between Medications

Physicians Desk Reference (PDR)
Physicians Desk Reference (PDR)

A medication is contraindicated when there is an existing condition that makes its use inadvisable. Certain medications can be contraindicated in specific groups of people (eg. pregnant women) or in combination with other medications (eg. aspirin and warfarin). Basically, some medications are contraindicated with one another because taking them together is known to cause potentially serious problems. This section discusses how to learn more about medications and avoid negative drug interactions.

How Do Acne Scars Form?

Ice Pick Acne Scars on Cheek
Icepick Acne Scars on Cheek

Acne scars are the result of tissue damage caused by inflammatory acne. The vast majority of acne scars are caused by from persistent cases of inflammatory acne affecting the same area of skin. Individuals who suffer from frequent nodular and cystic acne outbreaks (Acne Types: 3-4) are at a very high risk of developing permanent acne scarring. This is particularly true when a region is affected by overlapping acne outbreaks, with no opportunity for the skin to completely heal between outbreaks. This section discusses the different factors that contribute to the development of acne scars.

Frequently Asked Acne Questions

Frequently Asked Acne Questions

There are many claims about what causes acne and what treatments are effective for improving acne symptoms. Some of these claims are entirely true, some are partially true, and many are completely false. There is also a tremendous amount of contradictory information about acne available from lots of different sources.

In this FAQs section we address the most common acne-related questions on topics such as diet, hygiene, bacteria, hormones and more. For in-depth discussions the scientific aspects of acne, refer to our Acne Science page.

What is Acne?

Type 3 Acne on Forehead
Type 3 Acne on Forehead

Acne is a difficult to treat and often debilitating disease that affects the skin, usually the face. The most common form of acne (acne vulgaris) is an infection within a hair follicle. This infection causes varying degrees of inflammation, which manifest as pimples, nodules and cysts. When the inflammation is severe, it can cause permanent damage to the skin and create acne scars. This section covers the basics of what acne is and the different types of acne.

What Causes Acne?

Inflammatory Acne Papules Skin and Cellular View
Inflammatory Acne Papules Skin and Cellular View

Acne is a complex disease and many factors can contribute to the development of acne symptoms. Every case of acne is unique and the blend of factors that cause acne varies between individuals. This section contains a list and discussion about the factors that are major contributors to the development of acne symptoms.

What is the Best Acne Treatment for Me?

Over The Counter (OTC) Acne Products
Over The Counter (OTC) Acne Products

Choosing the best acne treatment(s) for each individual depends on many factors. The type and severity of your acne, your age, gender, treatment history and personal preferences are all important. If possible, you should work with your dermatologist or healthcare provider to develop a comprehensive acne treatment plan that is specifically tailored to your needs. Treatments for active acne and acne scars can be roughly divided into 6 different categories: Over The Counter (OTC) Treatments, Pharmaceutical (Rx) Treatments, Naturopathic/Homeopathic Treatments, Light & Laser Treatments, Surgical Treatments and Acne Scar Treatments. This section contains detailed information about all of the available acne treatments.

What are the Different Types of Acne Scars?

Rolling Acne Scars on Face (Woo)
Rolling Acne Scars on Face (Woo)

Acne scars come in many different shapes, sizes and even colors. Each type of acne scar has its own unique characteristics and features. Because of these differences, the available treatments for acne scars are not one size fits all. It is important to carefully choose the treatment that best matches your needs in order to achieve optimal results. Acne scars can be classified into three main groups: Depressed (pitted scars), Raised (keloid scars) and Discoloration scars. This section discusses the different types of acne scars and the features that define each group.

How Do Acne Scars Form?

Ice Pick Acne Scars on Cheek
Icepick Acne Scars on Cheek

Acne scars are the result of tissue damage caused by inflammatory acne. The vast majority of acne scars are caused by from persistent cases of inflammatory acne affecting the same area of skin. Individuals who suffer from frequent nodular and cystic acne outbreaks (Acne Types: 3-4) are at a very high risk of developing permanent acne scarring. This is particularly true when a region is affected by overlapping acne outbreaks, with no opportunity for the skin to completely heal between outbreaks. This section discusses the different factors that contribute to the development of acne scars.

Is acne caused by dirt or not washing my face enough?

Facial Cleansers are Popular OTC Acne Products
Facial Cleansers are Popular OTC Acne Products

The answer is usually NO. In most acne lesions (pimples, nodules, cysts, etc.), the site where the infection and inflammation is centered is not near the surface of the skin. Instead, it is near the base of the hair follicle where the sebaceous gland attaches. This is a region of the follicle that is not readily accessible from the surface. Therefore, cleansers and their active ingredients are unlikely to impact the inflammatory processes that drive moderate to severe acne symptoms (Acne Types: 2-4). This section discusses the benefits, risks and uses of acne facial cleansers.

Is Popping a Pimple a Bad Idea?

Popping a Pimple
Popping a Pimple

The answer is that it can be, especially if done improperly. Some pimples and other acne lesions benefit from being drained or popped in order to remove pus and accelerate healing, but other pimples should be left alone to heal on their own. The nodules and cysts of those patients who suffer from severe inflammatory acne (Acne Type: 4) are often lanced and drained by a dermatologist. This can prevent further damage and limit post-acne scarring. The important thing is to identify those zits and pimples which can be effectively popped (and which ones can not), and to do that properly and in a sterile fashion. This section discusses the risks, benefits and techniques for draining acne lesions.

Does Greasy Food, Milk or Chocolate Cause Acne?

Does Pizza Cause Acne?
Does Pizza Cause Acne?

The answer is probably not. Anecdotal associations between acne and particular foods like chocolate, ice cream and pizza have largely been discredited by scientific research. But research does point to a connection between overall diet and the development of acne symptoms. Researchers have shown that people whose diets include lots of high glycemic index foods (foods that are high in sugar and simple carbohydrates) tend to experience acne at a greater frequency than those who have low glycemic index diets. However, there is no clear scientific consensus on why this connection exists. This section discusses several of common claims about the association of specific types of food and acne symptoms.

What Does Non-Comedogenic Mean?

Acne Patients Should Avoid Comedogenic Substances
Acne Patients Should Avoid Comedogenic Substances

Comedogenicity refers to the potential of a substance to cause a comedo, a plugged or inflamed pore. Non-comedogenic means that in testing, the substance or product has not been shown to cause comedos (clogged or inflamed hair follicle). Some substances (eg. coal tar) are highly comedogenic and produce a type of allergic, acne-like reaction. There is not a clear consensus when it comes to the comedogenicity of many substances, with different tests yielding different results. This section discusses what comedogenicity is, how it is tested and which products and substances are likely to be comedogenic.

Can Stress Cause Acne?

Stressed Out
Stress

Stress can inhibit the function of the immune system and trigger or worsen acne symptoms It is well known that putting an organism under stress makes it more susceptible to infection. This is true for humans, animals and even plants. The same neural and biochemical pathways that make stress feel uncomfortable can also disrupt the delicate balance of a properly functioning immune system. This section discusses the relationship between stress and the development of acne symptoms.

What is the Relationship Between Acne, Depression and Suicide

Diagram of Psychological Impact of Acne (Magin)
Diagram of Psychological Impact of Acne (Magin)

Acne can have a profound negative impact on the psychological well-being of acne sufferers. Acne can increase the risk of bullying, depression and suicide.
For the millions of people who have suffered with acne, the psychological toll of the disease is well understood. The face is the window that connects one’s consciousness with the outside world. The face is also an essential factor in how the outside world perceives an individual. More than any other part of the body, diseases that affect the appearance of the face can have severe emotional and psychological consequences. This section discusses the connections between acne, stress, depression and suicide.

Is Acne Different Between Men and Women?

Acne Tends to be Different Between Men and Women
Acne Tends to be Different Between Men and Women

Yes, and it mostly comes down to hormones. Men and women tend to experience acne differently. Men are more likely to develop acne during puberty and are more likely to develop severe and inflammatory forms of the disease. Acne symptoms tend to peak during adolescence and recede during a male’s mid 20’s. In contrast, women tend to experience less acne and less severe acne than men, but rates of acne actually increase for women in the 20-40 age range. This section discusses key differences in acne symptoms between men and women, and why these differences exist.

What is the Relationship Between Pregnancy and Acne?

Pregnancy can Trigger Acne Symptoms in Some Women
Pregnancy can Trigger Acne Symptoms in Some Women

There are a tremendous number of changes that take place in the female body during pregnancy and these changes can have both positive and negative effects on acne symptoms.
Many women experience dramatic changes in their acne both during and after pregnancy. Hormones that control the natural processes of menstruation and pregnancy have wide ranging effects throughout the body. Onset of acne or a worsening of acne symptoms is very common during pregnancy. At the same time, a smaller percentage of women report an improvement in their acne symptoms during pregnancy. This section discusses the effects that pregnancy can have on acne symptoms.

Anabolic Steroids and Acne

Arnold Used Lots of Anabolic Steroids
Arnold Used Lots of Anabolic Steroids

Anabolic Steroids (aka Roids, Juice, AAS, etc) are molecules that mimic the shape and function of androgen hormones (eg. Testosterone). Anabolic Steroids are generally used to stimulate protein synthesis and muscle growth. They are widely used as performance enhancing drugs (PEDs) in athletics. Anabolic steroids should not be confused with corticosteroids, which are immune suppressants and can actually inhibit muscle growth. Corticosteroid injections are sometimes used to treat acute inflammation in severe acne lesions. Anabolic Steroids are never used as an acne treatment, and their use can cause or worsen acne symptoms. This section discusses the biology of anabolic steroids and their role in the development of acne symptoms.

What is Propionibacterium acnes?

Propionibacterium acnes (Toyoda, et al)
Propionibacterium acnes (Toyoda, et al)

Propionibacterium acnes (P.acnes) is a bacteria that can colonize the the skin and hair follicles. Excessive growth of this bacteria in the skin contributes to acne vulgaris. Propionibacterium acnes (P. acnes) is a bacteria that grows deep inside of pores, where it feeds on the sebum that is produced by the sebaceous glands that surround the base of the hair shaft. Most individuals with acne symptoms have an overgrowth of P. acnes bacteria in their skin. Several research studies have indicated that specific strains of P. acnes bacteria are commonly associated with acne vulgaris. This section details what P. acnes bacteria are and how it contributes to acne symptoms.

What is Acne?

Type 2-3 Acne on Face

Acne is a difficult to treat and often debilitating disease that affects the skin, usually the face. The most common form of acne (acne vulgaris) is an infection within a hair follicle. This infection causes varying degrees of inflammation, which manifest as pimples, nodules and cysts. When the inflammation is severe, it can cause permanent damage to the skin and create acne scars.

Types of Acne

Acne can range from small patches of red skin with tiny bumps to large cysts that are painful to the touch. Different types of acne can have profoundly different underlying causes and understanding precisely what type of acne you have can help you identify what solutions are going to have the best chance of being effective.

Type 1 acne

Type 1 Acne on Forehead

 

  • Minimal inflammation.
  • Minimal affected area.
  • Not painful.
  • Irregular outbreaks.

 

 

Type 1 Acne is the most mild form of acne and generally is the least damaging and easiest to treat form of the disease. It is characterized by a lack of inflammation and is usually not particularly painful. The area of the body affected by the acne is usually limited. This type of acne is often transient and often resolves on its own after about a week. Non-inflamed blackheads and small red bumps (papules) are common with this form of acne. This form of acne appears to be particularly common in females and often affects the forehead, cheeks, nose and neck. Topical treatments are often effective at resolving the symptoms associated with Type 1 acne.

Type 2 Acne

Type 2 Acne on Forehead

 

  • Mild inflammation.
  • Some painful pimples.
  • Regular outbreaks.

 

 

Type 2 Acne is similar to Type 1 acne, but is characterized by increased levels of inflammation and more frequent outbreaks. With Type 2 acne, pimples can range from small red bumps to medium sized whiteheads. Unlike Type 1 acne blemishes, the increased inflammation causes pimples that are often painful to the touch. Over-The-Counter (OTC) topical treatments are often partially effective at decreasing the severity and duration of outbreaks, but are frequently inadequate for Type 2 acne. Topical antibiotics, Topical Retinoids and Light-Based Therapies can be quite effective for this type of acne. In some instances it may be necessary to explore oral antibiotics or oral retinoids, if the acne does not respond completely to topical treatments. In general, Type 2 acne is minimally scarring if allowed to resolve on its own. However, it is important to practice good hygiene and avoid exacerbating the situation by “popping” pimples without cleaning and sterilizing the area before and after.

Type 3 Acne

Type 3 Acne on Forehead

 

  • Large, painful pimples.
  • Nodular pimples.
  • Frequent outbreaks.

 

 

Type 3 Acne is characterized by the presence of medium to large nodules and pustules that are frequently painful. With Type 3 acne, pimples are often associated with significant amounts of inflammation. Large whiteheads and large, painful red bumps (nodules and cysts) are common. Individual pimples can take a long time to resolve, up to 10-14 days. In type 3 acne, much of the inflammation and infection originates deeper in the skin tissue than in Acne Types 1 and 2. Because the source of the problem is deep within the skin, Type 3 acne is usually unresponsive to OTC medications, and many other topical treatments. The efficacy of topical antibiotics and topical retinoids is often limited for people with Type 3 acne. In many cases, oral antibiotics, oral retinoids (Isotretinoin) and laser-based therapies are the only effective treatments. The increased inflammation associated with Type 3 acne poses a significant risk of permanent scarring.

Type 4 Acne

Type 4 Acne on Face

 

  • Large and painful nodules.
  • Abundant Pustules and Cysts.
  • Persistent Outbreak.

 

 

Type 4 Acne is the most severe form of the disease. In most cases, Type 4 acne will cause permanent skin damage and scarring. Like Type 3 acne, Type 4 acne is characterized by inflammatory infections deep within the hair follicle and surrounding tissue. Large, painful cysts and nodules are a common feature in Type 4 acne. Type 4 acne is is generally completely non-responsive to OTC medications. Topical antibiotics, topical retinoids and naturopathic treatments are poorly effective in many cases. Type 4 acne is a serious medical condition that should be evaluated and treated immediately by a dermatologist, if possible. Treating Type 4 acne often requires aggressive treatment regimens that combine topical and oral pharmaceuticals. Type 4 acne is often extremely painful, both physically and psychologically.

Acne Treatments

Physician

What is the best acne treatment for you?

Choosing the best acne treatment(s) for each individual depends on many factors. The type and severity of your acne, your age, gender, treatment history and personal preferences are all important. If possible, you should work with your dermatologist or healthcare provider to develop a comprehensive acne treatment plan that is specifically tailored to your needs.

Treatments for active acne and acne scars can be roughly divided into 6 different categories: Over The Counter (OTC) Treatments, Pharmaceutical (Rx) Treatments, Naturopathic/Homeopathic Treatments, Light & Laser Treatments, Surgical Treatments and Acne Scar Treatments. Click on a category below to explore specific treatment options in greater detail.

Over The Counter (OTC) Treatments

Over The Counter (OTC) Acne ProductsWhen most people first develop acne symptoms, they initially turn to Over The Counter (OTC) acne products. These products are generally topical medications and they are widely available at grocery stores, department stores and pharmacies. Common OTC acne products include face washes, creams, masks, astringents and pore strips. Many of these products contain one of two active ingredients – Benzoyl Peroxide and Salicylic Acid.

Pharmaceutical Treatments

Oral AntibioticsFor many individuals with moderate to severe acne (Acne Types: 2-4), Pharmaceutical Treatments are required to significantly improve their acne symptoms. Pharmaceutical treatments include oral and topical medications that are available primarily from a clinician or pharmacy. There are many different types of Pharmaceutical medications that are used in the treatment of acne, including Antibiotics, Retinoids and Hormonal Treatments.

Naturopathic Treatments

Sweet MintMany modern medicines are derived from natural products that have been used in traditional medicine for thousands of years. Many plant extracts and other natural products have properties that can be helpful for individuals with acne. Naturopathic/Homeopathic acne treatments include include Essential Oils, Herbal Supplements, aromatherapies, special/restrictive diets, nutritional supplements and more.

Light & Laser Treatments

Blue Light PhototherapyLight and Laser therapies are available for the treatment of both active acne and acne scars. Light-based treatments such as Blue Light Phototherapy can be valuable additions to a comprehensive acne treatment regimen. Laser-based treatments such as Fraxel are among the most effective treatments for established acne scars.

Surgical Treatments

Acne Scar Subcision ProcedureSurgical Treatments are available for active acne and acne scars. Many dermatologists routinely perform simple surgical procedures such as comedome (blackhead) extraction for their patients. Individuals with severe inflammatory acne may have nodules and cysts that may need to be surgically lanced and drained, in order to heal. Surgical Treatments are often the best option for patients with Moderate to severe acne scarring. There are many types of surgical Treatments for acne scars, including Chemical Peels, Microdermabrasion, nNedling, Subcision and more.

Acne Scar Treatments

CROSS TCA Acne Scar TreatmentAcne Scars can be difficult to repair, but fortunately there are many different kinds of Acne Scar Treatments available.  The best treatment for an individual with Acne Scars depends on the type and severity of their scars. Treatments specifically for Acne Scars can be found in each of the categories listed above. This section contains a collection of treatments, selected from the above categories, that are specifically useful for treating acne scars.