Acne vulgaris: a clinical update

[Music] Welcome to the Australian Prescriber Podcast, an independent no-nonsense podcast for busy health professionals.

Hello and welcome to the Australian Prescriber Podcast. I'm Jo Cheah, a hospital pharmacist in Melbourne and your host for this episode. In this episode, I have the pleasure of interviewing Dr. Belinda Welsh, dermatologist in private practise at Complete Skin Specialists and consultant dermatologist at the Skin Health Institute and the Royal Children's Hospital in Melbourne. Welcome, Belinda.

Thank you so much for having me on, Jo. It's an absolute pleasure.

It's a pleasure having you. So, I'm sure some of our listeners, myself included, have had pimples or blackheads before. So, how common is acne vulgaris, and who does it affect the most?

Well, it's incredibly common, and nearly all of us actually have experienced pimples or blackheads or some form of acne. And a lot of the big studies done around the world show that up to 85% of adolescents and young adults will get acne. And in Australian general practise, it would be in one of the top 5 reasons people would come to see a GP for skin problems. There's a big burden of disease from acne, and it's not to be underestimated.

Absolutely. And is it more common in females, for example, than males?

Well, interestingly, it tends to be common across males and females, but adolescent males will tend to have more severe nodular cystic and truncal disease, and that probably reflects the androgen exposure for them. Adult women will tend to carry a greater long-term burden.

So, roughly about 20 to 40% of women will actually continue to have clinically significant acne well into their 20s and 30s. And some of them, we talk about this post-mature acne, but a lot of women may actually not develop it until they're 25 or more. It's actually quite a complex disease, and there's a lot of individuality. So, that group of women will tend to have longer disease periods, so more likely to have repeated cycles of antibiotics over their lifetime because of the chronicity.

Acne is not just some condition that you have as a teenager, and it's just going to get better automatically. It is actually a condition that is, for many people, chronic. So, that really changes our thoughts about how we manage it, what sort of expectations we put on it. And more and more, we're seeing people with skin of colour coming to this country and living here. And for a dermatologist, that can be quite a challenge because we have to get better at recognising the signs and symptoms of all skin disease, but including acne. And that group has quite a high burden of post-inflammatory pigmentation, which can extend well beyond them having had their acne.

Very important to understand that it affects both males and females, and it may look different across ages and life stages. Beyond what I mentioned, pimples and blackheads, what are the clinical features of acne, and how would you go about diagnosing it?

You would think acne's a pretty easy spot diagnosis, but actually there is quite a bit of nuance. One of the key defining features of acne is looking for comedones. So, 'comedones' is our medical term for blackheads and whiteheads. That is really the separator of acne from other conditions. Look for open comedones, or blackheads, closed comedones, whiteheads, polymorphism. So, what I mean by that is you've got lesions in all stages of evolution. The distribution is important.

Acne will happen on seborrheic areas, face, chest, and back. Sometimes it'll extend onto the shoulders, but it's the areas where we've got the most oil glands. When you're diagnosing it or looking for it, the other really important thing to do is look for evidence of scarring, because again, that is going to change your management approach and really make you more inclined to treat more aggressively to manage that acne because of the sequelae.

So, atrophic scars, ice-pick scars, or hypertrophic or keloid scarring. Now, keloid scarring will tend to occur on the trunk and the jawline, and that really is more challenging to treat. So, post-inflammatory erythema, post-inflammatory hyperpigmentation, all these features can be in the one patient at the one time.

To add onto that, another feature of acne could also be the psychological impacts it has on patients.

Yeah, Jo. So, the psychosocial burden of acne is huge. And lots of listeners to this podcast are probably going to be seeing a lot of teenagers and young people, and it's hard enough to be a young person in 2026, let alone adding acne.

What we recognise is that a lot of big studies have shown that depression, anxiety, even suicidality are significantly increased in acne patients. Also, that psychosocial burden is not proportional to the lesion count. So, some patients can have what we might consider mild acne, and yet the impact for them is really significant. That's where spending that little bit of time and trying to understand what that is for each individual patient is really important.

There are many misconceptions about what causes acne, such as poor hygiene. So, what are the actual causes of acne, and perhaps some risk factors as well?

So, one of the strongest determinants of acne is genetic susceptibility. That's a very strong determinant, not only of developing acne, but of disease expression and how severe it is. Twin studies have shown that there's actually quite high heritability. And if there is a parent or a sibling with scarring acne, that's a very strong prognostic signal that that's a possibility in the patient in front of you.

There's low-to-moderate evidence for those modifiable risk factors, so high-glycaemic load diet, dairy intake. The strongest signal there is actually for skim milk, stress, obesity, and other metabolic disorders like polyendocrine metabolic ovarian syndrome.

There is no doubt, though, that those factors are important to consider, but just addressing those alone isn't going to fix the acne. My personal experience is year 12 acne is a real thing. Year 11 and 12, it coincides with the peak time of acne expression, but at the same time, it's really stressful for kids. And then there's those practical day-to-day things like very occlusive cosmetics, hair products, especially if there's a lot of acne on the forehead, those waxes and occlusive hair products may be causing a problem, but a lot of it is genetics.

So, what's involved? Why does it become apparent? The pathogenesis is there's basically 4 interlocking mechanisms. First is androgens. They drive sebaceous gland activity, and that increased sebum production, adrenarche is the first factor. And there's actually altered lipid composition. So, the fatty-acid lipid composition does change, which is more pro-inflammatory. The second thing is there's abnormal follicular keratinization. So, the oil gland gets enlarged under the influence of those hormones. And then the duct that leads to the surface of the skin develops some abnormal thickening on the inside.

So, there's this follicular hyperkeratinization, and that means that the oil is less likely to drain out, and it gets blocked. That's the first thing that happens, and that's that microcomedone that develops. So, once you've got that stagnant pool, the bacteria make their way down into the sebaceous gland and cause infection. And that's C. acnes (Cutibacterium acnes), which is the most common one that does that. And there's actually particular phylotypes of C. acnes that are more pro-inflammatory than others.

This is where the genetics may come in. There's this dysregulated immune response. It's an augmented immune response to that process. And that's where we see this significant inflammation, which is beyond what should be necessary. And that's both innate immunity and also adaptive immune responses.

Acne is a very inflammatory condition, and all those things together lead to the clinical features that we see. There's this idea that acne is just a transition phase that you pass through and that you'll grow out of it. And that's actually not the case. So, I think that's where we need to be way more proactive in treatment.

That brings us to the next part of our chat, which is talking about various topical and oral therapies. So, for our listeners, what is the mainstay of treatment for acne?

Well, topical treatment really is the mainstay. Topical combination treatment where you've got a benzoyl peroxide product and a topical retinoid. And effectively, that's probably the one consistent treatment that we know is effective. It's easy to access for patients. And that really does act as an anti-inflammatory, anti-comedolytic, and helps restore that more appropriate follicular keratinization.

Usually they're available in a fixed-dose combination. And one of the biggest problems is adherence. I think that's where the work in the consult really has to be done, to make people understand how to use these products best, and that they need to be used for a minimum of 4 to 6 weeks, really out to 12 weeks. Persistence is key, and you have to be patient.

Daily skincare is critical for acne. And what I am very careful to ask about is, 'What are you actually doing?' A lot of patients are unfortunately shooting themselves in the foot by using products that are too abrasive, too strong, irritating, disrupting their skin barrier. And we try and pare all that back and keep it very simple. So, what we need is a sunscreen in the morning, a cleanser at night, and a moisturiser. There are a lot of cleansers out in the market.

Generally, a cleanser that might contain a little bit of salicylic acid is quite useful, because salicylic acid helps that cell turnover and reduces the blocked pores. But the moisturiser doesn't need to have harsh products in it. So, something that is lightweight and not too occlusive, perhaps a lotion, but that's very important to restore the skin barrier. And even studies where they've done placebo arms of active products in topical preparations, patients on the placebo arm with just a cleanser and moisturiser actually improved.

So, keeping that skincare really simple and adding in these products [topical acne treatments] at nighttime. So, if you're having a fixed product like a benzoyl peroxide and topical retinoid, cleanser first, and then the product, and perhaps a moisturiser over the top. Just start every second or third night, or even 2 or 3 nights a week, and then gradually build up. Retinoids can be irritating. And if you start using them every night, you'll perhaps cause retinoid dermatitis with flaking and redness. But if you build up very slowly, then your skin starts to tolerate it, and it's protected a little bit by that moisturiser.

The moisturiser can go on before the product or after the product, or maybe both. And if you're not using it every night, it doesn't matter, it's still going to be effective even at that low frequency. So, choosing a product is one thing, but trying to explain how to use it to people is the other important factor. Don't just use it on the pimples, use it on the whole face, because it actually acts on those pre-clinical lesions, the microcomedone, to try and prevent new ones coming up.

As the doctor, you can choose a benzoyl peroxide plus a topical retinoid, and we've got a few topical retinoids available to us in Australia. And that includes adapalene, tretinoin, trifarotene, and tazarotene. All of them work. Perhaps some of them are a little bit more irritating than others. So, adapalene probably is the least irritating, it's now available over the counter. Tretinoin is excellent and is now going to be TGA-listed for acne. And trifarotene is a good one if you are looking at treating the chest and back, because you've got a bigger tube and there's more product, and that was what it was indicated for.

There are combination treatments that you can use which involve topical antibiotics and topical retinoids and benzoyl peroxide. Duac Gel combines clindamycin and benzoyl peroxide, and Acnatac combines clindamycin and tretinoin. Epiduo or Epiduo Forte combines adapalene and benzoyl peroxide. So, Epiduo Forte contains 0.3% adapalene, and Epiduo is 0.1% adapalene, so the Forte is a little bit stronger..

So, for the most part, it's probably ideal to start with a benzoyl peroxide and retinoid if you can. And then [also] topically, we've got the newer clascoterone, which is a 1% cream, and that's a newer product that is a topical anti-androgen.

So, in women who are getting some cyclic flaring or that post-mature acne, that might be something that you could use either in combination with oral contraceptives or [oral] spironolactone, or in isolation if they didn't want a systemic treatment. So, we've got a lot of topicals available, but they are definitely the cornerstone of treating.

Interesting that patients may not see a meaningful impact on their condition maybe for about 12 weeks. So, it's important that they do stay compliant with their therapy. Would the patients then need to continue on the topical therapies beyond the 12 weeks as well?

Yeah. Acne is a long-term problem. Once it's under control, it's actually really important to maintain some sort of maintenance treatment. And usually that's the easiest with the topicals. It's all about getting into the habit of doing that skincare.

And in terms of an escalation to possibly oral therapies, do you mind just highlighting the most important oral therapies for acne, and potentially discuss whether they be prescribed by a specialist or a GP, and the main counselling or side effects that you would also mention for those as well?

So, most of the time, standard presentation, the first treatment option orally would be some oral antibiotics. We now are really mindful, because of antibiotic stewardship as well as efficacy, that we really don't want to be treating beyond 3 to 6 months. We do not want to be keeping people on long-term oral antibiotics for their acne anymore. If you've hit 3 months and you've not had a significant improvement, or you hit 3 months, it is improved, you stop it, and it comes back, you've really got to think about what's the next step, because we do not want to leave people on antibiotics.

The first choice would be doxycycline. That is my go-to. You can use from 50 to 100 mg. I find 100 mg a little bit more effective. It tends to be very well tolerated, in my experience. The most common side effect tends to be a little bit of gastrointestinal upset, so perhaps some reflux or a little bit of gastritis, but mostly not. Photosensitivity, definitely. And that's important to counsel people about, because treating over summer, they'll be a little bit quicker to burn, and they do notice that.

Minocycline would be an alternative. Macrolides, trimethoprim-sulfamethoxazole (Bactrim) would be reserved for patients who perhaps can't take tetracyclines for whatever reason, and erythromycin perhaps in pregnancy if necessary. Spironolactone is underused. Spironolactone is a very effective medicine for acne, particularly for women. Basically, it is an anti-androgen.

Starting dose is usually 25 to 50 mg a day, and you can titrate up to 100 mg a day. It tends to be very well tolerated. Its maximum onset is generally at about 3 months, and it's a good one to combine with the oral contraceptive pill. That can be because sometimes it makes periods a little bit irregular. It can cause a little bit of spotting or occasionally a bit of amenorrhea. And so, combining it with the pill is useful, but it's also very efficacious. But again, it requires time. It's really useful for those post-mature acne, jawline distribution, premenstrual flaring, that group.

So, I encourage GPs to use spironolactone a little bit more often, because it can be very effective. It's well tolerated. Hyperkalaemia, which is probably the thing that we worry about a bit, is actually quite rare. So, it's not necessary to be doing monthly blood tests to look for potassium. Maybe once every 3 months is completely adequate. And we only would be a little bit mindful if you've got patients who are on other potassium-sparing drugs. But on its own, it's very good.

Obviously, you would want to counsel about teratogenicity, because it could cause feminization of a male foetus. So, the next thing is obviously oral contraceptive pill, and I think the GPs are way better at treating and very comfortable using the pill. Generally, I would do that in conjunction with the referring doctor. But basically, pills containing drospirenone tend to be a little bit better, so that's Yaz/Yasmin, as they're less androgenic.

Finally, we come to isotretinoin, which is what most of the dermatologists would end up prescribing once patients get to us. And that is a remarkably effective drug. It's been around for about 45 years, and it's got a proven track record. And remarkably, it is still our go-to drug after all these years.

The article goes into a lot of detail about isotretinoin. Perhaps if you want to highlight some key counselling that you would provide to patients if you were starting them on it.

I always explain to them what it is and the mode of action, and it's not an antibiotic. It's actually a synthetic vitamin A molecule, and it works by shrinking sebaceous glands. It clears up that blocked duct, the follicular hyperkeratinisation, and it clears comedones. Antibiotics will not clear comedones, and nearly every patient will have some comedonal involvement.

Some patients are full of comedones, and the only thing that will really help them is isotretinoin. They're going to be probably on a course of treatment minimum of 6 months up to 12. The most important thing that we address is teratogenicity.

So, when I'm talking to women, we always talk about teratogenicity. Women need to do a baseline pregnancy test, and we get consent just so that they understand it's really important not to get pregnant while they're on it or for a month after stopping it. Second thing is dryness. Dryness of the lips is the most common side effect. Sometimes a little bit of angular cheilitis, sometimes some blood from the nose, and they can get a little bit dry inside the nose and dry eyes.

So, particularly in people who are using contact lenses, they can get a little bit dry in the eyes. Dry skin, need to moisturise and get into a habit of moisturising after the shower. The dryness tends to occur on the back of the hands and forearms, and is really something that needs to have a dose adjustment down to try and manage that. I'm very aware in patients with eczema, because they've already got that barrier dysfunction. They already tend to be dry, and it can really flare up patients with eczema if you're not careful. So, dryness is important.

Photosensitivity is the next one. Really careful over the summer months, because it's very easy to burn. Blood tests are not something that have to be done as regularly as we used to do. We can do some at baseline. Obviously, we need to do a pregnancy test if indicated, and then perhaps repeat them [blood tests] at 8 weeks. That is the standard recommendation, but there is some flexibility practically in that.

I am mindful that in adults, it [isotretinoin] can increase cholesterol and triglycerides. So, I'm very careful to check lipids in my adult patients and monitor that appropriately. The other thing that I mention is myalgias. This tends to be important in the young kids who are doing a lot of sport. And in particular, I find the kids that play football or basketball, they can get some myalgias and sometimes a little bit of lower-back pain. That also tends to be dose dependent. And so, dropping the dose will tend to improve that.

And then, of course, we come to what has been a bit of a cloud over isotretinoin over all these years, is this idea of mood alteration and effects on psychological functioning. It's always been somewhat controversial, this issue, and we know that large observational studies and meta-analyses have not shown consistent causal association between oral isotretinoin and suicide or psychiatric disorders. But we are also mindful that there is individual variability, vulnerability, and perhaps some rare, idiosyncratic reactions. We know also that mental health improves when acne clears.

We really try and do some baseline assessment of mood, anxiety. It's not always easy to get a sense of that, but certainly if there are co-existing treated psychological conditions, you want to work very carefully with the treating psychologist or psychiatrist during treatment.

And so, I spend a lot of time allaying anxiety about mood change and isotretinoin, but I'm also open to what patients are telling me. We can always stop it if we need to and restart it. It's got a short half-life. It's out of your system quite quickly, within a week or 2. So, if it was truly the drug causing that mood disturbance, then generally my experience is that, rarely, if it's happened, it's reversible. They are the most common things that we would talk about when we're treating with isotretinoin.

That's great, Belinda. I really appreciate your time and your passion during today's podcast. That unfortunately brings us to the end of our episode. Really appreciate you, Belinda, joining us today.

Thank you, Jo.

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The full article, Acne vulgaris: a clinical update, is available on the Australian Prescriber website. Belinda Welsh has received support from Candela, Galderma, and Novartis for educational activities. The views of the hosts and the guests on the podcast are their own and may not represent Australian Prescriber or Therapeutic Guidelines. I'm Jo Cheah, and thanks again for joining us on the Australian Prescriber Podcast.

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