Dr Tess McPherson

Brief Outline: Dr Tess McPherson is a Consultant Dermatologist and Senior Clinical Lecturer (Oxford University Hospitals). Her particular areas of clinical and research interests include paediatric dermatology, teenage and young adult dermatology, psoriasis, acne and eczema.

Background: Dr Tess McPherson is a Consultant Dermatologist, Senior Clinical Senior Lecturer at the University of Oxford and member of the British Society of Paediatric Dermatology.

Dr McPherson talks about when a person could seek a doctor’s help for acne.

At what stage should a young person to go to the doctors if they are having some spots?

I think there's lots of things that can be done for acne. The key is to do things before you've got scarring. So I don't think it's worth waiting and waiting. I mean, there's lots of things that can be used over the counter quite safely, initially. So there are some quite good, you know, products which are, you know, available without seeing a doctor. But I think if you're getting ongoing lesions, if you think you've got any kind of marks or scarring, you should absolutely go and see your doctor as soon as possible. And, or even if you know that you're kind of high risk, then it might be worth going to see your doctor, just to sort of get prepared. If you know you've had an older brother or sister that's had very bad acne, or a parent who's had scarring acne. I don't think- it's not something you need to kind of wait until things are really bad, because there are things that can be done.

Dr McPherson talks about acne causes and triggers.

I think it's always difficult to talk about the difference between causes and triggers. Most people, the cause of their acne is a normal part of puberty and adolescence, and it's to do with a, you know, complex mix of hormones. Particularly androgens, testosterone, which are higher during puberty. So we're not normally looking for kind of an underlying cause, because mostly it's quite well recognised that being in puberty you're kind of acne-prone. And that's partly because of the- mostly because of the hormones. And obviously because of those, the way those hormones will then increase sebum production, which in turn will make it a more favourable state for certain bugs. Particularly p. acnes to live on the skin and cause sort of more problems with acne. There are some other kind of rare causes. So you can have other reasons why you might have increased testosterone. For instance, taking anabolic steroids, or something like that. So very, very unusually there can be other causes. But mostly it's, you know, you’re more likely to have bad acne if you've got genetics or bad- family history, family history of bad acne, and then you're going through puberty. We know that boys tend to have more inflammatory acne in puberty, but girls can have more chronic acne as they get older. So, hormones are the main kind of cause. In terms of triggers, that's a bit more difficult to kind of untangle. Like any inflammatory state, stress can play a role. Which I think, you know, obviously when people find they've got a spot at an important point in their life, and you know, we know that stress can play a role in all of these processes. Other triggers are not so sort of clearly worked out. So people are often interested in diet. And it's a kind of area of increasing research. Probably some places, some places where they have very low dairy diets have very low acne, even in adolescence. So there may be some role for particularly high dairy diets, and that might have some role on the types of hormones and inflammation they have on their skin. Other triggers. So, smoking doesn't seem to make acne- so it doesn't make it better. It's not clear whether it makes it much worse. But mostly people will get acne, you know, even if they have clean skin, if they don't have kind of bad skin habits. It's just unfortunately a part of the way their genetics are and being a teenager.

Dr McPherson talks about what happens in skin with acne.

Okay. So we're just going to talk about acne [sketching]. So that's a close-up of the skin. That's your hair coming out of a hair follicle. And this is a sebaceous gland, which produces something called sebum into the surrounding area. So in acne you've got more sebum. And then you get kind of hyperkeratosis, and that sort of plugs up this pore, which is what you see as a pore in the skin. And then you can get bacteria and inflammation, and you can get pus and pustules. So there's different types of acne lesions. There’s the comedones, which are kind of we know as whiteheads and blackheads. And then you can get the pustules. And then obviously all of these can then lead to, in some cases, marks or scarring. Which is why we particularly want to, you know, treat acne, before you get any scarring. 

Dr McPherson explains about the drug isotretinoin (e.g. Roaccutane).

So they come from a family called retinoids. And that comes from something called vitamin A. And they have an impact on many of the processes that are implicated in acne. So they actually sort of work at a cellular level, reducing some of the sebum production, reducing some of the bacteria, and reducing the sort of hyperkeratinisation. So they seem to be very, very effective treatments for acne, if used in the right people at the right time. And, you know, 90 percent of people will see an improvement to clearance of their acne, particularly on a tablet form, but the topical treatment can be useful in certain cases as well.

Dr McPherson discusses the benefits and risks of isotretinoin treatments.

And it's for the most part a very well tolerated, very effective drug. And actually the benefits for most people far outweigh any risks. Most people on the treatment will get dry skin. And that's partly the way it works by, you know, making your skin less oily, less productive of sebum. And that's why it helps the acne. So, dry skin is almost to be expected. The other risk which happens in a lot of people is they can get a flare up of their acne when they first start using it. So it's maybe prudent to start on a low dose and kind of build-up gradually, so you don't get that flare up of your acne, which can be very disheartening. Also makes you more sensitive to the sun. So you have to be quite careful if you're, you know, sun-exposed or you've got fair skin. The other risks are really unusual. I mean, the main thing for females is they mustn't get pregnant. Because it does, you know, we know that it has a very- it's very something called teratogenic. So it's very likely to cause a problem with the fetus if you did get pregnant. And that's why it's important for them to be contraception or discuss the risks of pregnancy when they get prescribed this medication. But the other risks are really quite unusual. So we do monitor blood tests to look at liver function and the fat levels in people's bloods. But normally in young people, you know, these are unproblematic and it's very unusual to have problems with those. And it can occasionally cause muscle aches and pains. The thing which it's always been associated with and people are concerned about is mood and depression and even suicide risk. If that is associated, which it's not clear it is, it seems to be a very esoteric, individual, you know, thing that happens. Most people I see who start isotretinoin, their mood improves because their skin improves. And that's by far the most common psychological side effect, is that people feel better because their skin is better. But it does, you know, it takes a few weeks for things to settle down. And often the beginning it can be a bit, you know, they have to sort of wait for their skin to kind of get used to it, in a way. Whether it really causes severe depression and suicide is still unclear. And as I said, if it does, it's very much a kind of idiosyncratic reaction, which is not- you can't predict. So even if someone has had depression or even suicidal ideation, you can't- it's not a reason not to give them isotretinoin if their skin warrants it. And you wouldn't be able to predict if they were the sort of person that might have mood problems with it. Certainly if you look at big groups of people on and off this medicine, it's not- it's not clearly associated. And it's something which again, will be considered by any doctor, but mostly the benefits will outweigh the risks.

Dr McPherson says the link between diet and acne is unclear.

Yeah, I think there are lots of misconceptions. And it's not to do with having dirty skin or not washing your face. It's to do with the hormone levels and your sebum production and your genetics. And that's, that's normally nothing to do with, you know, your diet or how clean or dirty you are, what your food-, whether you eat junk food or not. You know, we do know that probably having a healthy diet, eating fruit and vegetables, is good for your skin generally. But the other way round it's not quite so clear. So I don't think there's a clear link between junk food and acne. And I know lots of-, I see lots of young people who have incredibly healthy diets and have acne in any case. So I think it's , it's not directly linked to the food you eat. Sunshine can help some people with acne, it can be- you know, it probably reduces inflammation and can help some, some people with acne. But you know, face washing is an important part of management, but certainly you can have very clean skin and still have acne. So I think unfortunately you can do everything right, look after your skin, eat lots of fruit and vegetables, and still get spots. And that's, you know, people mustn't feel that they're responsible for that.

Dr McPherson talks about the types of spots often involved in acne.

So acne has lots of different types of spots. Some people will have mostly one type, some people will have all different types. All spots come- are focused around something called the pilosebaceous unit and that’s where the hair grows out of a follicle, with a little sebum producing gland which is called the sebaceous unit. The earliest type of spots are mostly comedones and people will know these as whiteheads and blackheads, and those are called open comedones [blackheads] and closed comedones [whiteheads]. That’s really just a build-up of sebum and other stuff within the hair follicle. The more inflammatory type of spots are pustules and that’s when you get a different type of cell, called a white cell. And those are the ones which look like squeezable spots, so they look quite pus-y and they look quite different from comedones – most people will be able to tell the difference between a whitehead and a pustule. Then you can get more problematic or larger spots, you can get cysts, abscesses. And then you can get – from spots, you can get marks and scarring. And you know some of those scars can be more lumpy, hypertrophic or keloid.

Dr McPherson says there are different grading systems for acne severity used by medical professionals.

So there aren’t any, you know, very well recognised grading systems for acne. There’s lots of different types and some of them are more kind of global, so mild, moderate, severe, very severe. Some of them, for research purposes, might focus on things like spot counting. And some of them will also look at the different types of spots, so you’ve got comedones, pustules, cysts, scarring. These types of things. So, generally the kind of more global assessments are used when you’re using it sort of clinically and then decisions about treatment will be made on how severe the acne is, how much it’s affecting people, and also how likely it is to scar. So those are the most important things. Because really when you’re treating acne it’s not just for improving the acne as it is but also preventing scarring long-term because scarring can be permanent.

So, sort of terminology around mild through to severe-

Yeah.

- is that quite varied depending on-?

A lot of these grading systems are quite subjective so it depends on the doctor that’s doing it. And so people have different levels of severity. But there are certainly picture-, kind of picture grading systems which can be quite useful in terms of, you know, how much of the face is affected, how severely it’s affected, how tight together the spots are. And that will be-. So I think there is quite variable but I think there is quite close agreement for some of those grading systems between doctors and other health professionals.

Dr McPherson says a patient’s views about their own acne will be taken into account by medical professionals when making decisions about treatment.

So clearly some people will have more-, classed as mild acne but it might be having a huge impact on them and some people will have more severe acne which isn’t affecting them at all. And people’s experiences are very varied. And that will have implications for treatment because some people will be much more keen to try a treatment with possible side-effects with a milder form of acne than other people. So these decisions are often made with the doctor, health professional, patient in conjunction with taking all these factors into account. I think as a health professional if you think the acne is very severe and is scarring, you’ll probably be trying to persuade someone to take treatment that they might not feel comfortable with. But on the other side, you might see people with very minimal acne who are very keen to have treatment and you’ll have a more- different conversation. But it’s always going to be a balance between the severity as judged by the activities that you see clinically and the likelihood it’s going to scar and how much impact it’s having on people.

And I think there are some types of acne which people become quite obsessive with, you might have a lower threshold for treating. So some people who become obsessed with picking and squeezing at spots, then actually treating them at a lower level is probably sensible because they, you know, you want to try and reduce all inflammatory acne and help them with those aspects of things.

Dr McPherson explains why isotretinoin treatments (tablets and topical gels) are usually only available from dermatologists.

So traditionally when it was a new medicine and it was found to be very effective for acne, there were concerns about its safety and its side-effects. Particularly the psychiatric side-effects and it was- when it was first being used, it had links with depression and even suicide in certain people. So I think there was quite a lot of concern about its use first of all and it was certainly being used, you know, it had quite a high threshold for use. And the other reason for care with its use is the pregnancy prevention programme. So if you’re on isotretinoin and you’re female, it’s, you know, it’s very dangerous to get pregnant and there would highly likely be a problem with the baby if you did get pregnant. So for those reasons, so partly the kind of concern about side-effects, partly the need to monitor things, particularly pregnancy side, it’s traditionally been prescribed only in hospitals by dermatologists. That may change in the future and I think as antibiotics have- have to be careful with prescribing antibiotics for their- they’re used quite a lot in primary care anti-inflammatory purposes for acne- for treating acne, but really if the side-effects of using the antibiotics is so widely more problematic than using something like isotretinoin which is a very effective treatment for acne earlier, then this may change in the future. There have been a few times when I think there- so some GPs with Special Interests can and do prescribe isotretinoin, but they have to be comfortable with monitoring the side-effects, monitoring the pregnancy prevention programme. And traditionally when that’s been kind of rolled out to General Primary Care unit, it hasn’t worked so well and they haven’t felt comfortable prescribing it. But these things are, yeah, may change in the future.

Dr McPherson talks about how common acne is and how long it tends to last for those affected

So it depends how you define acne in terms of-, most teenagers in this country will get spots to some degree. Whether they’ll all get acne is, you know, depends on where your definition and where your line lies. So I suppose if-, just having spots is very common, having acne that needs treatment either by your GP or by a dermatologist is not so common. But I think still within, you know, 15-20% of teenagers will have severity of spots or acne that needs treatment, so it’s very common. And that will depend on thresholds as to how- how people access healthcare or access treatment.

And how often does it tend to last for people who do have some aspect of acne?

Yeah. So the evidence is that the prevalence is very high and then it slightly depends on what sex you are. So boys tend to have worse acne that lasts probably shorter and they may be more likely for it to not last beyond their teenage years. Whereas girls can have less severe acne but it can grumble on into their 20’s and particularly if they have a more hormonal type of acne or it seems to get worse around their cycle, those types can become- can carry on into their 20s and even 30s. All of these can be like modified by treatment, but there are particular patterns that tend to be a bit more chronic. So sort of jawline acne in females can be more problem- more chronic without treatment.

Dr McPherson talks about the benefits of the Health Experience Insightswebsite for young people and health professionals.

I think the Health Experience Insightswebsite offers so many benefits for young people and I’ve already seen young people finding it really useful to find that support online. A lot of these conditions have similar issues in that people often feel alone with their symptoms and alone with the visible differences that they’re having to cope with. And that I think can happen, you know, whether you’ve got acne, eczema, psoriasis, alopecia or any other things which are affecting your skin, hair, nails and can have an impact on how you feel and how it affects you in your normal life and how you socialise and, you know, enter adolescence and the workplace. So I think collecting other people’s experiences and seeing how other people have coped and struggled and- I think it has such a power in helping people find solutions to issues and coping with problems, which many of these skin conditions and hair conditions can give them.

I think this site has massive- massive implications for education and health professionals. I think the power of seeing people speak about conditions not in a medical setting, not when they’re seeing their doctor, has such a strong message for how to manage things, how these diseases affect people in ways that we’re really not- we don’t know when we just see them in the clinic. And I think- so it has big implications and benefits for being able to use for education and for other people – carers, health professionals, teachers, anyone engaged with young people with skin disease, to learn more about these conditions.