Acne vulgaris is the most common type of acne, caused by clogged pores, bacteria, and inflammation
Acne vulgaris is acne that forms when dead skin cells and oil (sebum) block your pores, bacteria grow inside, and your skin becomes inflamed. It is not caused by dirt, poor hygiene, or eating certain foods. It happens because your skin produces more oil than usual, your pores shed skin cells unevenly, or bacteria called Cutibacterium acnes (formerly called Propionibacterium acnes) multiplies in the blocked pore. Most people get acne vulgaris at some point, especially during puberty when hormones trigger increased oil production.
Acne vulgaris shows up as blackheads, whiteheads, small red bumps, or larger painful cysts. It appears most often on the face, chest, shoulders, and back—places where you have the most oil glands. The severity ranges from a few occasional spots to widespread breakouts that leave scars. Understanding what is actually happening inside your skin helps you recognize which treatments might work and why some approaches fail.
Key Takeaways
- Acne vulgaris forms when pores become blocked by oil and dead skin cells, allowing bacteria to multiply and cause inflammation.
- Hormones, genetics, and skin type determine how much oil your skin produces and how prone you are to breakouts.
- Blackheads and whiteheads are non-inflammatory acne, while red bumps and cysts are inflammatory and more likely to scar.
- Acne vulgaris is not caused by chocolate, greasy food, or poor washing—these are myths that can lead you toward ineffective treatments.
How a pore becomes blocked and turns into a spot
Your skin constantly sheds dead cells from the outer layer. Normally these cells wash away. In acne vulgaris, the shedding becomes uneven—cells stick together inside the pore instead of moving out. At the same time, oil glands in that pore produce more sebum than usual. The combination of trapped cells and excess oil creates a plug.
Once the pore is blocked, the environment inside becomes airless. Cutibacterium acnes bacteria, which live normally on all skin, thrive in this oxygen-free space and multiply rapidly. Your immune system responds to the bacterial growth by sending white blood cells to the area, causing redness, swelling, and the sensation of tenderness. This is inflammation. The type of acne that forms depends on how deep the blockage sits and how severe the inflammation becomes.
Blackheads, whiteheads, and inflammatory acne are different stages
Blackheads (open comedones) form when a pore is clogged but stays open to the air. The material inside oxidizes and turns dark—the black color is not dirt. Whiteheads (closed comedones) form when the same blockage happens but the pore closes over, trapping the material beneath the skin surface. Both are non-inflammatory; they do not cause pain or swelling.
Inflammatory acne develops when bacteria multiply enough to trigger a strong immune response. Papules are small red bumps without a head. Pustules are similar bumps with a white or yellow center (pus). Nodules are large, painful, firm bumps deep in the skin. Cysts are the largest type—fluid-filled, often very painful, and most likely to leave permanent scars. Inflammatory acne is what most people think of when they picture a bad breakout.
Hormones, genetics, and skin type drive acne vulgaris
Acne vulgaris runs in families. If both your parents had acne, you are more likely to develop it. Genetics influence how much oil your skin produces, how your pores shed cells, and how your immune system responds to bacteria. You cannot change your genes, but understanding that acne is partly inherited helps you stop blaming yourself or your habits.
Hormones called androgens increase oil production, which is why acne often starts or worsens during puberty, menstruation, pregnancy, or when taking certain medications. People with oily skin are more prone to acne vulgaris than those with dry skin, though acne can occur on any skin type. Stress does not cause acne directly, but it can trigger hormonal changes that increase oil production and worsen existing breakouts.
What acne vulgaris is not
Acne vulgaris is not caused by eating chocolate, pizza, or greasy food. Large studies have found no consistent link between diet and acne in most people, though some individuals report that certain foods (dairy, high-glycemic foods) seem to trigger breakouts for them personally. Acne is not caused by not washing your face enough or having dirty skin. In fact, over-washing or scrubbing harshly can irritate skin and make acne worse. Acne is not contagious—you cannot catch it from another person.
Acne vulgaris is also not a sign of poor character, laziness, or that you are doing something wrong. It is a biological process involving your skin's oil production, cell shedding, bacteria, and immune response. Shame or guilt about having acne does not change the underlying mechanism and can actually make stress-related flare-ups more likely.
Why acne vulgaris can leave scars
Inflammatory acne—especially nodules and cysts—can damage the deeper layers of skin (dermis) where collagen lives. When inflammation is severe or lasts a long time, your skin may not rebuild that collagen evenly. This creates indented scars (atrophic scars), raised scars (hypertrophic scars), or discolored marks. Non-inflammatory acne like blackheads and whiteheads do not typically scar.
Picking or squeezing acne, even when it looks ready to pop, increases inflammation and the risk of scarring. The bacteria and debris get pushed deeper into the skin instead of draining safely. Scars are permanent, though treatments exist to reduce their appearance. This is one reason dermatologists recommend treating acne early and avoiding manipulation.
When to see a dermatologist about acne vulgaris
You can start with over-the-counter products containing benzoyl peroxide or salicylic acid if you have mild acne (a few blackheads, whiteheads, or small red bumps). These work by reducing bacteria and helping pores shed cells more evenly. If acne does not improve after 6 to 8 weeks, or if you have moderate to severe inflammatory acne, nodules, cysts, or acne that leaves scars, seeing a dermatologist makes sense.
A dermatologist can prescribe stronger treatments like topical retinoids, oral antibiotics, hormonal birth control (for people who menstruate), or isotretinoin (for severe acne that resists other treatments). They can also assess whether what you think is acne vulgaris might actually be rosacea, folliculitis, or another skin condition that looks similar but requires different treatment. Early treatment of severe acne vulgaris reduces the chance of permanent scarring.
Frequently Asked Questions
Is acne vulgaris the same as regular acne?
Yes. Acne vulgaris is the medical name for the most common type of acne. When people say "I have acne," they usually mean acne vulgaris. Other types exist (acne rosacea, acne mechanica), but acne vulgaris accounts for the vast majority of cases.
Can acne vulgaris go away on its own?
Mild acne often improves with time, especially after hormonal changes settle (like after puberty ends). Moderate to severe acne usually does not clear without treatment. Even if it does improve, waiting risks permanent scarring. Treatment speeds healing and reduces that risk.
Does stress cause acne vulgaris?
Stress does not directly cause acne vulgaris, but it can trigger hormonal changes that increase oil production and worsen existing breakouts. If you notice your acne flares during stressful periods, stress management may help, but it is not a replacement for treating the acne itself.
Can you get acne vulgaris as an adult?
Yes. While acne vulgaris is most common in teens and young adults, it can start or continue into your 20s, 30s, and beyond. Adult acne is often linked to hormonal changes, medications, skincare products, or stress. It responds to the same treatments as teenage acne.
Is acne vulgaris permanent?
Acne vulgaris itself is not permanent—breakouts come and go, and most people's acne improves with age or treatment. However, severe inflammatory acne can leave permanent scars. This is why treating acne early, avoiding picking, and seeing a dermatologist for severe cases matters.