Acne Explained: Causes, Types and How to Manage Breakouts

What happens inside a pore

Every pore on your face is the opening of a hair follicle attached to a sebaceous (oil) gland. Acne starts when four things combine: the gland produces more sebum than usual, dead skin cells lining the follicle stick together instead of shedding, the bacterium Cutibacterium acnes multiplies in that oily, low-oxygen plug, and the immune system responds with inflammation.

Hormones — especially androgens — increase oil production, which is why acne often appears at puberty, around periods, during pregnancy, and with conditions such as polycystic ovary syndrome (PCOS). Genetics play a large role too: if your parents had significant acne, you are more likely to.

The main types of acne

Dermatologists group acne lesions into non-inflamed and inflamed types. Knowing which you have matters, because they respond to different ingredients.

• Blackheads (open comedones): a plug at the surface of the pore. The dark colour is oxidised oil and pigment, not dirt.
• Whiteheads (closed comedones): the same plug, but trapped under a thin layer of skin.
• Papules: small, red, tender bumps without a visible head — the follicle wall has become inflamed.
• Pustules: inflamed bumps with a white or yellow centre of pus.
• Nodules and cysts: large, deep, painful lumps under the skin. These carry the highest risk of scarring and usually need a doctor.

Common triggers

Triggers do not cause acne on their own, but they can make an existing tendency worse. Heavy or occlusive cosmetics, hair oils that run onto the forehead, friction from helmets, masks or phone screens, high humidity, and stress are frequent culprits. Some medicines, including certain steroids, can also cause breakouts.

The link with diet is more modest than many people believe. Some studies associate high-glycaemic foods and skimmed milk with worse acne in some individuals, but no single food is a universal cause. If you suspect a food, keep a simple diary for a few weeks rather than cutting out whole food groups.

A simple routine that works for most people

Consistency beats intensity. Most active ingredients take 6 to 12 weeks to show their full effect, and switching products every few days makes it impossible to tell what is working.

• Cleanse morning and night with a gentle, fragrance-free, non-comedogenic cleanser. Avoid harsh scrubs — they inflame active spots.
• Use one proven active ingredient: salicylic acid (BHA) for blackheads and whiteheads, benzoyl peroxide for red, inflamed spots, or adapalene, an over-the-counter retinoid in many countries, for both.
• Moisturise with a light, oil-free product. Acne treatments are drying, and an irritated barrier can make breakouts worse.
• Wear broad-spectrum sunscreen every morning. It also reduces the dark marks that spots leave behind.
• Do not squeeze or pick. It pushes inflammation deeper and is the main cause of scarring and post-acne marks.

Acne marks versus acne scars

Flat brown or red marks left after a spot heals are called post-inflammatory hyperpigmentation or erythema. They are not true scars and usually fade over months, faster with sun protection and ingredients such as niacinamide or azelaic acid.

True scars change the texture of the skin — small "ice-pick" holes, rolling dips or raised bumps. They do not fade on their own, which is why preventing deep, inflamed acne early is so important.