Health & Beauty

A Dermatologist’s Guide To Understanding Acne

By Sophie Oddo
11th Aug 2021

A lady with fresh clean skin and her eyes closed.

If you’ve ever had the misfortune of experiencing acne (FYI, more than 80% of us have), then you’ll know it’s the absolute pits. Not only can it prove to be difficult to treat effectively and manage, but it can also take a serious toll on your self-esteem and confidence.

So, to help combat this hugely common skin condition, we’ve teamed up with trusted skincare experts La Roche Posay to uncover everything you need to know about acne. We sat down with Dermatologist Dr. Harriet Cheng to uncover all things acne and the active ingredients to look out for. 

Acne is a disorder of what we call the 'pilosebaceous unit', which made up of the hair and oil glands in the skin. There are a few changes to that unit that happen in acne compared to healthy skin. The unit gets blocked leading to blackheads and whiteheads. You get an accumulation of oil in the blocked unit and often people who have skin prone to acne produce more oil as well. As a response to all of that, you get inflammation—and that’s what causes a pustule. If it’s severe enough, then that inflamed unit can rupture. That’s when you get really deep inflammation leading to nodules and cysts.

Acne can be classified by severity. In mild acne we see comedones (blackheads and whiteheads). Those are really common and you’ll see those in mild, moderate, and severe acne, but it’s really the first change that you’ll see. In moderately severe acne there’s more inflammation with redness and pustules and then in severe forms of acne we see cysts and nodules which are much deeper and can scar. The other way we can classify acne is to look at how it affects people at different ages. The most common type is teenage acne. More than 80% of people get some form of acne in their teenage or young adult years as opposed to adult acne which happens after the age of 25. Adult acne is much more common in women and often affects the lower face or jaw line. 

There are a lot of myths about what causes acne. A lot of people think it’s a bad diet, bad hygiene, or not washing your skin enough. But actually, most acne is genetic. So it’s that genetic tendency to have overactive oil glands and oil glands that get blocked. There are other influences as well, such as hormones, and certain medications can lead to acne (such as steroids and some anticancer drugs). What you put on your skin can make acne worse as well, particularly occlusive, heavy and oil-based products or wearing a lot of cosmetics or makeup.

Most acne starts around the time of puberty because that’s when the oil glands start working. It’s most common to have acne in teenage, adolescent and young adult years. But a lot of adult women actually experience acne as well. So it really can affect you throughout your whole life. 

That depends on a lot of factors. It depends on: the severity, the person and their general health, other medications they’re taking at the time, or other medical conditions. For mild acne, there are things available without prescription that I'll recommend and that can be very helpful. These include anti-microbial products which balance the normal bacteria and yeast etc. that live on the skin and help to reduce the number of harmful bacteria. Examples include benzoyl peroxide and azelaic acid and there’s been some research recently into probiotics—so that’s an area to watch out for. Then are products that are anti-inflammatory, such as niacinamide and vitamin C. Exfoliants can also be particularly helpful for blackheads and whiteheads. Those are ingredients like salicylic acid, alpha hydroxy acids and retinoids. These chemical exfoliants are often better tolerated and more gentle than gritty physical exfoliants.

There are also products to help combat after-effects of acne, like redness or pigmentation or to combat the side effects of the other active ingredients. A lot of acne treatments are really drying. To help with this look for gentle cleansers and ingredients such as ceramides and niacinamide.

Urban List recommends: When it comes to dermatologically tested products, we love and trust (especially for sensitive skin) La Roche-Posay’s Effaclar range. It's a must for anyone suffering from acne-prone skin. Our go-to product is their Effaclar Duo+ anti-acne moisturiser. Including chemical exfoliants such as salicylic acid and Lipohydroxy acid (LHA) to help remove excess sebum, reopen clogged pores and reduce blackheads, and pimples for clearer skin. The formula also contains Niacinamide (Vitamin B3), Procerad™, and Mannose work together to brighten skin, help prevent pigmentation, and stimulate cellular turnover. Try with Effaclar Foaming Gel for a complete anti-acne skincare routine.



For treatment of severe acne—or if the acne is mild but it’s having a more significant psychological impact—there are stronger treatments that your doctor may prescribe. There include hormonal treatments such as the oral contraceptive pill which work because the pilosebaceous unit is under the influence of hormones, producing more or less oil depending on hormone fluctuations. The other treatment your doctor might recommend is antibiotics. For acne, were not trying  to wipe out all the bacteria on the skin; the antibiotics instead have an anti-inflammatory effect. Because of that, the dose is often lower and the course is longer (most often three months). Even so we need to be cautious with antibiotics used long-term, so if the acne doesn’t respond, or relapses after treatment then other treatments should be considered. Often hormonal treatments and antibiotics are combined with prescription creams or gels containing retinoids. These are stronger than the retinoids available over the counter without a prescription. It’s important to remember that these acne treatments work slowly, often improvement takes at least a few weeks.

For severe acne (or when the acne is having a severe impact on that person's life) then oral retinoids may be an option. The most commonly prescribed oral retinoid is isotretinoin and it works by shrinking the oil gland down, treating the underlying cause of acne. In New Zealand isotretinoin is available on prescription from your GP or your dermatologist. There are side effects to consider and isotretinoin cannot be taken during pregnancy.


Because most acne is genetic, it’s really hard to prevent, however, early treatment is important to prevent scarring, redness and pigmentation. Most people will outgrow acne but scarring can be permanent!  Having a diet high in sugar can play a small role, but it really has much less of an impact on acne than genetics does.

Having good skincare, washing your face twice a day and avoiding heavy oils and makeup helps. There are certain ingredients to look out and avoid e.g. cocoa butter and isopropyl myristate but in simple terms, if you look for products that are labelled as 'non-comedogenic' that means they’re less likely to block pores.

Yes, acne can be caused by wearing a mask because it creates a humid and occlusive environment. To avoid mascne, make sure you’re using gentle and non-comedogenic skincare, not wearing makeup under the mask, taking breaks from wearing the mask, and if you're seeing acne flare-ups make sure to treat it early when it starts.

A better life for acne-prone skin is possible with La Roche Posay’s Effaclar range. To find out more about their range of products click here. La Roche Posay can be purchased from Chemist Warehouse, selected Life Pharmacy, Unichem and Independent pharmacies, or at

This article is brought to you in conjunction with La Roche Posay and proudly endorsed by Urban List. Thank you for supporting the sponsors who make Urban List possible. Click here for more information on our editorial policy

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