What Is Acne?

Why does a pore that behaved itself for years suddenly turn into a sore, raised spot? Acne starts smaller than you'd expect — inside a single hair follicle. The short 3D animation at the top of this page walks through that process step by step, showing how a spot forms under the skin and how treatment targets it. It runs about a minute and a half, and it makes the questions below much easier to picture.

It begins with a blocked pore — so what blocks it?

Your skin constantly makes an oil called sebum, which normally travels up the follicle and out onto the surface. Acne begins when that route gets crowded: extra oil mixes with dead skin cells that should have shed, and together they form a plug. Once the opening is sealed, oil keeps arriving behind the blockage with nowhere to go. That's the quiet first stage — nothing may be visible yet, or you might see a small bump where the plug pushes the surface up.

Why do some plugs stay pale and others turn angry?

A plug that stays under the skin's surface shows as a whitehead; one that reaches the surface and darkens on contact with air shows as a blackhead — the dark colour isn't dirt, it's simply the plug oxidising. Things change when bacteria that normally live harmlessly on the skin find themselves trapped in that warm, oily, airless space. As they multiply, the body responds with inflammation, and that's when a spot becomes red, swollen, and sore. Deeper inflammation can produce larger, tender lumps under the skin, which are the kind most likely to leave a mark if they're squeezed or picked at.

Why does it flare when it does?

If your breakouts seem to arrive on a schedule, you're not imagining it. Hormonal shifts — around puberty, monthly cycles, pregnancy, or starting and stopping hormonal contraception — can turn up oil production, which is why acne so often starts in the teenage years and why adult acne is common too. Friction and pressure don't help: tight straps, helmets, and resting your chin in your hands can aggravate the skin over the same patch again and again. Stress is harder to pin down, but many people notice their skin worsens during pressured stretches, possibly because stress and sleep disruption stir up the same hormonal background.

What happens at a dermatology appointment?

Expect questions before equipment: when the breakouts started, where they appear, what you've already tried, and whether anything seems to trigger them. The examination itself is usually just a close look — sometimes with a handheld magnifier like a dermatoscope — to judge how much of the acne is surface-level and how much sits deeper. That distinction drives the plan. Milder acne is often managed with treatments applied to the skin; more widespread or deeper acne may call for medicines taken by mouth, and some clinics also discuss procedure-based options, such as the laser treatment walked through in "Acne treatment with LASER". Whatever the route, acne treatment works slowly — skin needs weeks, not days, to show whether a plan is helping.

One habit is worth breaking early: picking. It pushes inflammation deeper and raises the chance of lasting marks, which is a different problem from acne itself. If breakouts are leaving marks, spreading despite a consistent routine, or simply wearing you down, that's reason enough to book the appointment. And if your skin trouble comes with widespread itchy, flaky patches rather than spots, our guide to eczema may be the closer match.

MedicalVideos.com has published trusted medical videos since 2007. The site was founded by Dr. Mohamed Ibrahim, MD, PhD — physician-scientist.

Frequently Asked Questions

Is acne caused by dirty skin? No. Acne forms inside the follicle, under the surface, so it isn't a hygiene problem — and scrubbing harder tends to irritate inflamed skin rather than help it. Gentle cleansing is about comfort, not about washing spots away.

Why do adults get acne if they had clear skin as teenagers? Because the drivers can switch on later. Hormonal changes, some medications, and shifts in skin products or routine can all raise oil production or clog pores in adulthood, even in people who never had teenage breakouts.

Do blackheads need to be squeezed out? It's best to leave them alone. The dark plug sits in a delicate follicle, and squeezing can injure the surrounding skin and turn a quiet blackhead into an inflamed spot. A clinician can advise on safer ways to manage them.

How long should I give a treatment before deciding it isn't working? Longer than most people expect. Skin renews itself gradually, so a fair trial is usually measured in weeks of consistent use. If there's no improvement after that, or the acne is deep and sore, a dermatologist can step the plan up.

Educational only — this article is general information about acne, not medical advice and not a diagnosis. Deep, painful, or scarring breakouts, or skin problems that persist, should be assessed by a dermatologist who can examine your skin.