What causes acne? Diagnosis, prevention, and treatment

Overview: What is acne?

Acne is a common chronic skin condition of the face, shoulders, upper back, and shoulders. Most people will have an outbreak at some point in their lives. Currently, 50 million people in the U.S. have acne, most of whom are teenagers. Hormonal changes during adolescence are the most common acne trigger, but adults can also be affected. During adolescence, oil glands in the hair follicles start producing more oil. Acne occurs when excess oil and dead skin cells block the opening to hair follicles, forming blackheads or whiteheads called comedones. Sometimes, bacteria that typically live on the skin will colonize the clogged hair follicle, resulting in red or pus-filled pimples. In more severe acne, the infection can spread deeper into the skin tissues and to other hair follicles, forming nodules or cysts. Although acne is not a health threat, it can be psychologically and socially devastating. Depression, anxiety, and social withdrawal are common complications. Even worse, persistent or severe acne can result in permanent acne scars. Fortunately, people with acne have a wide range of treatment options. Many are very effective, even in severe cases.

RELATED: How to treat—and prevent—teen acne

What causes acne?

The cause of acne is clogged pores. Multiple events may occur together or independently to clog pores and produce acne:

• Increased oil (sebum) production by oil glands (sebaceous glands) located in hair follicles

• Increased production of dead skin cells in hair follicles (hyperkeratinization)

• Blockage of the hair follicles by excess oil and dead skin

• Colonization of the blocked hair follicle by Cutibacterium acnes bacteria (formerly called Propionibacterium acnes)

• Inflammation (swelling and redness) due to the immune response to the dead cells and bacterial overgrowth

Increased oil production and the death of skin cells are usually triggered by hormone changes during puberty, setting off the chain of events that are causes of acne. Other hormonal triggers include pregnancy, the menstrual cycle, and polycystic ovarian syndrome.

Risk factors for acne

The skin changes at the start of the development of acne result from hormonal changes, particularly increases in circulating androgens. For this reason, the most predictive risk factor for acne is puberty and adolescence. About 85% of adolescents will experience a bout with acne before they turn 20. For many, the problem will persist for several years while they are teenagers.

The second-most predictive risk factor is a family history of acne. Researchers believe that inheritance accounts for 50% to 90% of acne cases. 

Other risk factors that may trigger or worsen acne include:

• Pregnancy

• Premenstrual flare-ups

• High humidity

• Heavy sweating

• Family history of acne

• Use of occlusive makeup

• Use of oily makeup or other substances on the skin

• Tight clothing or other pressure on the skin

• Side effects of certain medications such as corticosteroids, anabolic steroids, and lithium

Other possible risk factors include:

• Anxiety or emotional stress

• A diet high in sugary foods

• Excessive dairy intake

Is acne serious? When to see a doctor

By itself, acne is not a health threat. However, acne can be a source of significant distress and could have long-term effects on a person’s appearance and well-being. Severe acne can cause lifelong scars. While mild cases can be successfully managed through the use of over-the-counter medications, more severe or stubborn cases may require seeing a doctor or dermatologist.

How is acne diagnosed?

Healthcare professionals diagnose acne based on its appearance and a history of the symptoms. Not every acne outbreak is acne. Other common skin conditions that may look like acne include folliculitis, rosacea, and seborrheic dermatitis (dandruff). The doctor, dermatologist, or other healthcare professional will first rule out other possible skin conditions. The second order of business is to determine the severity of the acne. The healthcare provider will note the amount of skin affected, the number of lesions, the risk of acne scars, and the effect of acne on a person’s quality of life or psychosocial wellness in determining whether the outbreak is mild, moderate, or severe.

A medical history will help the clinician determine the cause, such as hormones, drugs, or cosmetics. Healthcare professionals will usually not perform any tests unless they suspect another medical condition, such as folliculitis.

Is acne hereditary?

Heredity is a highly predictive risk factor for acne. Having family members with acne doesn’t guarantee an acne problem but increases the likelihood. Anywhere from 50% to 90% of acne cases are associated with inherited genes. Heredity also plays a role in the early onset and severity of acne. Heredity also explains many cases of persistent adult acne. Anywhere from 38% to 70% of adults with acne also have an immediate family member with adult acne.

The role of heredity in acne is complex. Some genes may make people prone to overproducing skin oil. This may help explain adult acne. Other genes may affect the types of fats produced by sebaceous glands. Some people may have genes that cause excessive skin cell death. Different genes affect the severity of the body’s inflammatory response. 

Is acne curable?

In most people, acne will clear up without treatment in early adulthood, usually around 20 years of age. Treatments can help reduce acne lesions and severity and even clear the skin. The treatments will be based on the severity of the case. They include:

• Gentle washing of the affected area

• Physical extraction of comedones

• Over-the-counter topical acne and blemish medications such as cleansers, moisturizers, creams, lotions, antiseptics such as benzoyl peroxide, peeling agents (salicylic acid), and anti-inflammatory agents (azelaic acid)

• Topical antibiotics such as erythromycin or clindamycin for mild or moderate acne

• Oral antibiotics such as doxycycline, minocycline, or tetracycline for moderate, severe, or stubborn acne 

• Hormone therapy (birth control pills)

• Anti-androgen drugs such as spironolactone

• Retinoids such as isotretinoin or tretinoin for moderate, severe, or treatment-resistant acne

• Localized steroid injections for cystic acne

• Oral corticosteroids for extremely severe acne

• Phototherapy

Acne scars may require additional treatment such as chemical peels, dermabrasion, laser resurfacing, or collagen filler injections.

RELATED: Acne treatments and medications

How to prevent acne

Acne itself as a skin condition cannot be prevented, but outbreaks can be partly prevented and minimized through a few measures:

• Gently wash the face, back, and shoulders using soap and water—avoid harsh or abrasive soaps

• Avoid comedogenic makeup or sunscreen that contains oils such as cocoa butter or substances that block pores such as butyl stearate; look for oil-free, non comedogenic sunscreen and makeup

• Avoid wearing tight clothing or putting continuous pressure on areas subject to acne flare-ups

• Eat foods high in vitamin A, omega-3 fatty acids, and zinc

• Avoid high-glycemic foods

• Cut back on dairy products

• Reduce and manage stress

RELATED: The best diet for acne

FAQs about acne causes

What causes back acne?

Back acne, or “bacne,” has the same causes as facial acne: clogged pores due to the overproduction of skin oil by the sebaceous glands. However, there may be other factors at work triggering or worsening the problem, such as sweat, sweaty clothing, tight straps, backpacks, or sports equipment—all these can create a skin environment that narrows or closes pores, making oil buildup and clogs more likely.

What causes baby acne?

About 20% of newborns have neonatal acne. These aren’t actual pimples, however. While there are several presumed causes, one includes a skin reaction to a yeast infection called Malessezia. Newborn acne usually resolves by 6 weeks of age. Infants are less likely to have pimples than newborns.. The incidence is more like 1 in 50. However, infantile acne is true acne with blackheads, whiteheads, pimples, nodules, and even cysts. In these cases, the problem may be as simple as a reaction to soaps or detergents, or may represent a hormone imbalance. The advice of a dermatologist may be beneficial in the setting of infantile ance. 

What foods cause acne?

There is no evidence that any foods cause acne. However, certain types of foods can make acne breakouts worse. At the top of the list are foods high in sugar. Dairy products are another common culprit if they’re consumed in excess. What about chocolate? More than one study has suggested that dark chocolate consumption worsens acne. As with dairy products, healthcare professionals believe there’s a connection but are uncertain how much chocolate is too much.

What’s next? Additional resources for people with acne

Test and diagnostics

• Acne vulgaris, Merck Manual

• Acne vulgaris: diagnosis and treatments, American Family Physician

Treatments

• Acne (acne vulgaris), Merck Manual

• Acne clinical guideline, American Academy of Dermatology (AAD)

• Acne treatments and medications, SingleCare

• Acne vulgaris, StatPearls

Scientific studies and clinical trials

• Prevalence, severity, and severity risk factors of acne in high school pupils: a community-based study, Journal of Investigative Dermatology

More information on related health conditions

• Acne scar treatments and medications, SingleCare

• Folliculitis treatments and medications, SingleCare

• Rosacea treatments and medications, SingleCare

• Seborrheic dermatitis treatments and medications, SingleCare