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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.

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Dr McPherson talks about growing up and getting older with eczema.

Dr McPherson talks about growing up and getting older with eczema.

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Why does eczema clear up for some people as they get older, but not for others?

It's a really important question. And we really, if we had the answer to that we might understand more about eczema in general. There's various theories, and it's probably going to be complex, just as eczema is complex. It's probably going to be a combination of changing your skin barrier as you get to certain ages, changing the way your immune system works as you get older. Possibly exposure to certain infections on the skin, which might change the way that your immune sort of system responds to things. We don't really know. But I think it's only, it's also probably only in a, you know, minority of people that their eczema completely clears up. Most people will still have prone-, prone skin to developing for instance in the future hand eczema, and also these other kind of allergic atopic conditions such as hay fever and asthma. So really we should think of it more as a chronic life-long condition. And what we want to do is try and prevent it being bad, you know, as early as possible. Rather than, you know, promising everyone their eczema is going to clear up. Because I think that's often-, the young people I look after, that's often when they feel quite despondent, when they get to their teens and they've still got eczema, yet they were told all through their early life that it was going to clear up. And probably only, you know, only a minority of people their eczema completely clears up. And if you've still got it in your teens, you're likely to have it then ongoing into life. Not that it can't be controlled, but that you are going to have ongoing problems.
 

Dr McPherson talks about some of the most common types of eczema.

Dr McPherson talks about some of the most common types of eczema.

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So the most common type of eczema we see in children and young adults is something called atopic eczema. And that's often something which starts in babies, and it's a very complex disease, but it's mostly to do with a problem initially probably in the barrier of the skin. So, how kind of intact the skin is. And then because of the skin being kind of leaky it loses water, so you can get quite dry skin, and it also means you can develop further problems such as allergy in some cases. So that's by far the most common sort of eczema, which is called atopic eczema. There's a few other types, which some people, you know, can have problems with. So there's one called contact eczema, which is when you're kind of actually allergic to something that goes on the skin. And we tend to see that, sometimes it can be alongside atopic eczema but it can be also in older people or different types. Some certain jobs are at high risk, for example hairdressers, people that are in contact with certain things. And there's two types of contact eczema. One's irritant, where you're just being, you know, exposed to things that irritate the skin. And one's an actual allergy. But they all look very similar, they can all look very similar kind of clinically in terms of the skin being red and dry. And then the other kind of big group of eczema is something called seborrheic eczema. And that's one which really tends to affect the face. So the seborrheic areas are where you produce more sebum, so it tends to the places where you’d otherwise get acne. So forehead, eyebrows, round the nose, and sometimes scalp and back. And that's a different type of eczema which seems to have a kind of yeast, which is on the face and scalp, which can cause a particular type of eczema. Sometimes you see that in babies, but you can also see it in adults. So it's quite common. It's actually, you know, cradle cap that we see in babies is a form of seborrheic eczema as well. 
 

Dr McPherson explains the links between asthma, allergies, hay fever and eczema.

Dr McPherson explains the links between asthma, allergies, hay fever and eczema.

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So this is something that we know quite a bit more about in the last ten years, really understanding eczema, is- you know, it's a complex condition which is a mixture of your immune response and your skin barrier. So it's both things going on. And we know that in quite a lot of people they have-, they're born with a slight difference in their skin barrier function, and there's a protein called filaggrin, which is quite an important genetic association. If you have mutations in filaggrin, your skin is- your skin barrier function is not the same as someone that doesn't have. So, right from birth you have a slightly leakier skin. So that means two things, that you have this dry skin but it also means that you have this barrier dysfunction. So that means the allergies can- things can enter through the skin and cause problems. So that's, we think now there's a sort of sequential called an atopic march, where you start off with this barrier problem with the eczema. And then due partly to the eczema, you then get exposed to certain things in the environment such as grass, pollens. And that leads to sort of development of hay fever. And in some cases then again, this sort of exposure-, this exposure to allergens through the skin, can then lead to the development of things like asthmas as well. So that's why some of them it's to do with your immune response being overactive, and some of it's to do with your skin barrier being suboptimal. So it's those two things working together which mean you get this whole complex process.

And that's why some of it runs in families. So atopy we know is partly genetic, and some of it is to do with how well you manage your eczema, probably when you're small, and that can reduce your risk we think of going down this pathway.

And there's been an increase in eczema and other allergies over the past few decades, which is more than you would expect if this was just a genetic condition. So we know that it's not just people's genetics, it's a combination of environmental exposure, the way we manage eczema, the way we manage these other allergic conditions alongside, you know, the way your skin is when you're born.
 

Dr McPherson explains about the skin and how this functions differently in eczema.

Dr McPherson explains about the skin and how this functions differently in eczema.

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Okay. So this is a cross section magnified, of normal skin. And you can see all these cells here are all squished together nice and tight. This is a hair coming out, so you can see how small these cells are. If you think about like a brick wall, that's a normal, that's what normal skin looks like, the bricks are all nice and tight together. Now if you have a condition like eczema, so you've got inflammation, the cells become a little bit more gappy, the barrier function's not so good, for various reasons. So that means you can lose water. And that's what makes your skin dry, because you're losing water from your skin. And you can also have things like infections, and allergens - not very clear - can access the skin more easily. And that means that they come through and they're more exposed to immune cells. And that's how you can develop over-reactions or allergies to certain things. So we know that, you know, the first thing that really needs to be done is to help keep the barrier function good. And that's with kind of regular emollients. And reduce the inflammation, because that can also kind of lead into a vicious cycle of all these cells getting inflamed and spreading apart. And it means there's more immune cells around, if there's lots of inflammation. So that's done with topical corticosteroids. So that's why we use emollients, to help with the barrier function. And the corticosteroids to help with the inflammation in eczema. 
 

Dr McPherson talks about why allergy tests aren’t offered to everyone with eczema.

Dr McPherson talks about why allergy tests aren’t offered to everyone with eczema.

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So, why are people with eczema not always given allergy tests?

Because most people with eczema aren't actually allergic to anything. So mostly children with eczema, young people with eczema, have - they do have a higher risk of allergy because their skin is leaky. And we're looking at more ways of improving their- reducing their risk of getting allergies, by really directing skin- you know, sort of skin-targeted measures. So, increasing the barrier function by emollients, and reducing inflammation. Because those are the two things which happen first of all. In the most part, allergies develop on the background of bad eczema. So, I mean, we now know a little bit more about that, that actually what probably happens is that if their skin- because we know their skin barrier is, is sort of leaky, they're more prone to allergens entering the skin and developing allergies. It's very common for people with eczema to develop things like hay fever, and occasionally asthma. And really, the only reason for allergy tests is if you're going to change your management, if it's going to affect what someone does. So we know that they have a quite high risk of being sensitised to normal things in the environment such as grasses, pollens, trees. But really, that information is not going to change what you do because you can't avoid grasses, pollens and trees. So allergy testing to those is not that useful. The only time that we actually do allergy testing is when it's going to change what we do. And that's probably in the context of food allergy. 

People would love to have a test that said why they got eczema, and have one particular thing that they can avoid or change in their lifestyle. Unfortunately it's such a complex process, and they're probably over-reacting to lots of different things, and that's only part of the reason why they got eczema. So it's not that we can do a test and say, “Okay, you can avoid tomatoes, and you're not going to have eczema again.” That's not really going to be the case. So actually the only time we really do allergy testing is if they've had a, what we call an immediate response to food. And in that case, you know, they're almost- it's almost, they almost know that they've got this allergy anyway. But for very young children, allergy testing can be useful. Generally for older children, unless they, you know, they've got an immediate reaction to food, then just doing a lot of allergy tests is not very useful. There are two different types of allergy testing. So there's the one that you look the kind of immediate type response, which is something called IgE. And that would be, so food allergies can cause that, and you would be able to test that either by a prick test on the skin or a blood test, which is called a RAST test, IgE. The other type of allergy is the contact eczema that we talked about briefly. And that would be looking at doing something called patch testing, to see if there's anything that they're reacting to on the skin, left on the skin. So it's a different type of reaction that tends to take longer to come up, and it'll come up as a form of eczema. And that again is only really indicated if you've got an in depth suspicion that they might be reacting to something that's going on the skin, such as a topical treatment or something like that. It's a very complex area. And it's certainly not, you know, it's not advisable just to do lots of allergy tests if you can't use the information usefully and it's not going to change how you manage your skin and your other conditions.
 

Dr McPherson talks about how steroids work and the different kinds used for eczema.

Dr McPherson talks about how steroids work and the different kinds used for eczema.

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How do the topical steroids work?

Okay. So these are all really good questions. And, you know, we don't have very good answers to all of them. Topical steroids are quite kind of- they work in lots of different ways. So it's not a very sophisticated targeted treatment, but we know that they reduce inflammation. We know that when they're used on the skin, there's very minimal absorption. So, you know, they're safe to be used on the skin. We know that they're very effective in eczema, we've got lots and lots of studies which show the benefits of topical steroids far outweigh any risks. And there are risks to using the wrong strength of steroid for the wrong amount of time in the wrong body area. But mostly, your doctors or dermatologists will advise you sensibly to use the right strength topical steroid. And if anything, we're probably moving towards using slightly more potent corticosteroids topically, to try and keep the inflammation well controlled, rather than using inappropriately weak ones which never get it under control. So how they work is complex. But we do know that they do work, and that they're safe to use.

So, corticosteroids do come in lots of different potencies and strengths, and they have lots of different names. But, you know, it can be quite confusing I think for different people. So it's best if you have a kind of plan which shows, tells you which one you're going to be using. Often we use a different one for the face than all the rest of the body, just because the skin is thinner on the face. Most people we find under-use their corticosteroid treatment, rather than over use it. And it's very unusual to see side effects from the use of corticosteroids, because I think people are quite cautious, often overly cautious, with their use. So we would normally use a moderate to potent corticosteroid on the body, to control eczema. And we'd use it once a day. And most of them, they all need to be used really just once a day, for one to two weeks. And then we do something called proactive treatment. So we treat the flare-prone areas with weekend use of these corticosteroids to try and keep the activity of the eczema down. Because know that even when you're not seeing eczema, there's a lot inflammation in the skin. And so we, you know, by knowing this, we know that we have to treat those flare-prone areas regularly for some time in some people.

We would use, normally use a mild to moderate for the face. And, you know, with the eyelids, can be particularly- they are, you know, one area that you do probably need to be a little bit cautious about is around the eyes. And that's where we might use something like Protopic, or tacrolimus, topically to those areas. Which is a non-steroid anti-inflammatory, which works on the inflammation of eczema as well.
 

Dr McPherson talks about the importance of using steroids as instructed by informed medical professionals.

Dr McPherson talks about the importance of using steroids as instructed by informed medical professionals.

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Most of the patients that I see have been under using corticosteroids. And they often get almost inappropriate steroid phobia, and they get that from other health professionals – they sometimes get it from pharmacists, it can come at them from lots of different areas. And that comes from probably misinformation, a lot of the time. And, you know, not good knowledge on good use of how these products work and how they can be used safely. The NICE guidelines are very clear on this, they say the benefits of topical corticosteroids outweigh any risks. And that's, that's, you know, we know that, we have good studies to support that. We find that often people will be inappropriately cautious, and they'll have very active eczema. You know, because they're not using their corticosteroids effectively, or they're not being advised or supported in the effective use of corticosteroid use. If you use a very potent corticosteroid for a very long time on skin that's not inflamed, then you can run into side-effects. So I always think calling it ‘steroid phobia’ is a bit unfair, because it's, you know, it's not like you shouldn't be aware and mindful of possible side effects of treatments. But also you should be able to use them effectively. And if anything, we're using slightly more potent corticosteroids in a slightly different way, to make sure that we can reduce inflammation. Particularly early on in the, you know, in a child with eczema, because we think that's probably the most effective way to prevent them then getting, you know, more sustained and chronic eczema.
 

Dr McPherson talks about the differences between steroids and tacrolimus creams.

Dr McPherson talks about the differences between steroids and tacrolimus creams.

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Yeah. So the steroids have a more kind of general - neither-, both of them we don't know exactly how they work on the body, because even if you, you can see how something works in the lab, we don't know exactly how it works in such a complex inflammation as eczema. And we know that corticosteroids are probably overall slightly more effective than the tacrolimus type medicines particularly for the body. But for areas where you are worried about steroid side effects, such as skin thinning and striae development and you've got very thin skin already, such as the eyelids, then something like tacrolimus is a very good alternative because it reduces inflammation, it's quite targeted, and it can be used safely on those areas without long term risk of skin thinning.
 

Dr McPherson talks about immunosuppressant tablets.

Dr McPherson talks about immunosuppressant tablets.

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So sometimes, you know- Normally, I find most of my patients, I can- we can control their eczema with topical treatments. But clearly there are, there's a subgroup where that's very difficult, where their disease is very severe, and you have to think about tablets or systemic treatments. And, you know, there's several different options. And we're currently kind of doing some research to find out which one's are the most effective and the most safe. The ones that we use regularly in practice is a tablet called methotrexate. Which is an anti-inflammatory medication which works both for eczema and psoriasis, actually, by reducing the kind of inflammatory state of the skin. It's a folate antagonist. And it's , can be very effective for both these diseases if needed. They do need regular blood tests, because it can have other possible side effects. So it's certainly something we think about carefully before we start. But in some people, you know, that is an option which we have to consider. And particularly in psoriasis sometimes. 

There are other tablets which can be used for eczema. There's one called cyclosporine. Which has been, traditionally was the sort of first line, but at the moment we're trying to see whether cyclosporine or methotrexate, which one is, is best used long term.

And the methotrexate is a safe, safe drug. Relatively safe drug. It's been used around a long, long time. So we're kind of very comfortable with using that one, and that's what most, most people will use first line at the moment. But we're doing some research to work out whether cyclosporine or methotrexate is best for eczema.
 

Dr McPherson talks about how common eczema is and how long it tends to last for those with the condition.

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Dr McPherson talks about how common eczema is and how long it tends to last for those with the condition.

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So eczema is extremely common. Again estimated around 1 in 5 children have eczema to some degree. And the question we always get asked is, “Are there-, you know, are children going to grow out of it?” So the evidence is that a lot of people’s eczema improves and seems to clear up around, you know, by the time they get into double figures, early teenage years. But that’s certainly not true for everybody and it’s certainly not something I tell people is going to happen because a lot of teenagers do have problems- ongoing problems with eczema. And even if their eczema feels like it’s improved, they still have the risk of getting other forms of dry skin and eczema – for instance, hand dermatitis, hand eczema, or facial eczema, on into their teens. If you have problems with eczema or severe eczema in your teenage years, then the likelihood is it’s something you’re going to have to some degree life-long. Doesn’t mean it can’t be managed or treated, it just means that you’re not going to, you know, magically grow out of your eczema. We also know that having eczema does give you risks of other diseases that can be associated called atopic diseases such as hay fever and asthma. So how long does it last, probably truly it’s a sort of life-long disposition but that doesn’t mean you’ll always have terrible eczema. It just means you’re someone who’s at risk of having eczema or other atopic diseases all through your life.

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