Tag Archives: Specifically Medical

Specifically related to medical education, in particular of intest to medical students

Sunburn

Sun burns!

Recent UK summers – that is, lack of sun – meant I had forgotten how uncomfortable sunburn can be, but with average daily sunshine of 9 hours for a Bermuda July I am ashamed to say I learnt the lesson once again.
😦

With apologies to the non-medical readers, this post has a distinctly medical theme, but I have tried to keep it jargon-free. I shall attempt to answer the following questions:

What happens to the skin in sunburn?
Why is it dangerous?
What are the best treatments?

Under the following headings:

Ouch it hurts – presentation
Serves you right – risk factors
How bad can it be? – assessment
I told you so, try vinegar – treatments
Never again – prevention

Ouch, it hurts!

I knew I was burnt because my skin was red, tender and warm – oh, and I had just been snorkeling for two hours just before lunch with a pea-sized amount of sun cream liberally rubbed onto my whole body (we will get to how much and how often later, but you will all be thinking, quite with reason, how inadequate my preparation was)

A few facts:
Sunlight is composed of UVA, UVB and UVC. In fact to call it “light” encourages a relaxed attitude, I should use the term “radiation”. We don’t need to worry about UVC, it is reflected off the upper layers of atmosphere back into space. Most of the sun’s radiation is UVA (95%) but during the midday hours (10-4) UVB is twice as high as in the rest of the day and it is UVB that burns. UVA is by no means innocent, it is associated with aging, though the precise physiology is unknown.

Now I tend to brown nicely and rarely burn (Fitzpatrick Skin Type III – if you are a medic, then go look it up, but briefly it is a descriptive scale devised in 1975, used for research and has no real predictive value, though Fitzpatrick himself, a Harvard dermatologist, might plead otherwise).

Nonetheless, two hours after lunch and I was beginning to blister, a sure sign of deeper skin damage. The redness, by the way, is caused by skin blood vessels dilating and is the start of an acute inflammatory reaction. It is supposed to occur some 3-4 hours after exposure, peak at 24 hours and resolve over 7-10 days. That I was red so soon after exposure suggested I was over-cooked.

Cooking is probably an apt description, though the tanning is not merely desiccation and carbonization of the upper layers, it has more to do with melanin. Melanin is there to protect the skin, it will reflect some of the UVB rays. In “normal tanning” first the melanin that is already in the skin darkens by oxidation and is redistributed. Then the skin increases the synthesis of new melanin over the next 1-2 days.
But where I had overdone things, mast cells in my skin (they are really fascinating if you want to look them up) were releasing histamine, serotonin and the alarming-sounding tissue necrosis factor (TNF). This led to prostaglandin and leukotrienes which in turn attracted neutrophils and so on …. (You can tell I could get quite excited about the chemical processes in the inflammatory response)

But it is not so simple as just the surface layers of skin dying and sloughing off, the damage is deeper, the actual DNA is affected, and it is this that leads to the increased risk of skin cancer.

20130815-103244.jpg

In the image the cells that can become cancerous are squamous cells, basal cells and melanocytes. The epidermis, top layer, is usually separated from the lower layers by the basement membrane, but in advanced skin cancer it will grow through this and invade the deeper layers.

While we are talking about damage, sun damage can also lead to cataracts, particularly in India and Pakistan. Like sun-induced skin cancer the risk relates to exposure in children and young people, groups least likely to take precautions like wearing sunglasses and hats.

Serves You Right

For some reason this phrase carries echoes from my childhood. And it is appropriate since I did know better. Risk factors for sunburn include fair skin, infants and children, high altitudes, low latitudes, and the biggest – exposure between the hours of 10 and 4.

WHO developed a UV Index as far back as 2002, but inconsistency in its use has led to it being of less use than it might be. For grades 1-2 it is safe to be out without sun protection, for 3-7 it is recommended to stay in the shade during midday hours, for 8+ best to avoid exposure and always use protection. Today, in Bermuda, the maximum UV Index is 9. (http://accuweather.com )

90% of malignant melanomas occur in skin types I and II. Dark skinned people may be protected to a degree from skin cancer but are still susceptible to eye and immune system damage. A dark tan on a white skin will offer only limited protection, perhaps equivalent to using an SPF 4 lotion.

But I did use sun screen! Hmm – an adult should use 34g applied 20 minutes before exposure AND every 40-60 minutes.

Don’t waterproof ones last longer? Actually not, they are merely resistant to being washed off quickly but they still can only maintain the SPF for 40-60 minutes. I feel somewhat misled by the advertising!

How bad can it be?

Google “severe sunburn” and there are thousands of images, some horrifying. In quite a few the bearer is wearing a stupid grin. I don’t have pictures of my sunburn, I am too embarrassed.

If you are medical and presented with sunburn then assessment is along the lines for any burn – remember dehydration and pain levels. “Sunstroke” presents with fever, chills and nausea so if your patient is shivering and looking ill they may need admitting – you will have to present your case well to the on-call medical team as nobody is keen to use an acute bed for sunburn. In UK, 2011-12, there were 287 acute admissions for sunburn. (Hospital Episode Statistics- http://hscic.gov.uk )

I told you so – try vinegar

What sort of vinegar? It is a grandmother’s remedy, and online you will find lots of conflicting advice on what sort and how to apply it – there is no difference between white, apple-cider or malt, apart from the smell. I have no idea how it works, nor do dermatologists. Baking soda, cornstarch paste, calendula oil …. The list is endless.

 

Turmeric! Yes I am not kidding, applying a thin paste once daily apparently provides relief from sunburn – that one I must try!

With a doctor hat on I would suggest after-sun gel, one with lidocaine in if available, ibuprofen orally and plenty of water to drink. Aloe Vera has been researched but not shown to improve recovery time. Systemic steroids have advocates but again there is little evidence they help and plenty of risks, they are of no benefit topically either.

Never again!

There have been some recent surveys of Australian youth which suggest that the messages to cover up and use cream are wearing thin and along with fewer using protection are increased numbers suffering sunburn.

Meanwhile an SPF 8 cream is no longer considered sufficient but SPF 50 creams now cost well over $20 (£15) for quite small tubes. What is in these potions that makes them so expensive? One Aloe Vera sun lotion has a list of 43 ingredients.
There is a lot of hype about antioxidants and their protective effects against cancers but I was sceptical about their effect topically. My reading suggests, however, that some (selenium, CoQ10, alpha lipoic acid) have supporting evidence for topical use at least with regard to the aging effects of sun. Others, such as Vitamin E, pomegranate, ginger and grape seed extract, are currently being researched. The main problem with antioxidants is that they tend not to be absorbed well through the skin, so another topic of research is novel methods of application.

One thing I did learn was that sunscreen suitable for adults is probably not advisable for babies and infants – I guess it makes sense, given that baby skin is so much more susceptible to damage. Children need oil-based emollients with inorganic filters and should not be using the organic filters that are used to create higher SPF creams, specifically not oxybenzone.

And one last comment on fake tans – these are merely chemical dyes that color the dead skin layer various shades of brown, they neither increase melanin nor even moisturizer the skin. They use dihydroxyacetate (DHA) which has been used in cosmetics since 1920s, and while they may be mixed with moisturizers or SPF creams, none currently available provide sufficient protection for use instead of a proper SPF50 lotion.

You have been very patient while I have learned my lesson, my husband has been sympathetic – last weekend he bought me an SPF50 shirt to cover me up when swimming next time. It is bright yellow, so not sure how good it will be for snorkelling, do fish get frightened by giant yellow things?

 

 

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Absolutely no oxygen

Yesterday in a shop I overheard a woman saying to her friend “My doctor sent me for lung function tests which showed that I had absolutely no oxygen in my lungs whatsoever, so no wonder I couldn’t breathe.”

Aside from the impossibility of this statement, which had me laughing behind the brightly-colored-ultra-fluffy-highly-expensive towels, the incidence of asthma in Bermuda is of interest.

A seminal study in Bermuda in1986 documented the effects of weather changes on acute asthma.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1341634/

The conclusions were that a NE wind with its colder air and lower humidity will precipitate acute asthmatic attacks while a SW wind, high humidity and higher temperatures seemed beneficial.

It was known as far back as 1776 that cold dry air triggered asthma ( Philosophical Transactions of the Royal Society of London, 1776) . Dramatic increases in incidence have occurred with the passing of cold fronts and thunderstorms in New Orleans, Birmingham UK, and Melbourne (Brown and Jackson 1983 Lancet ii, 260.) But Bermuda has a sub-tropical climate with temperatures not below 16C and generally high humidity all year round so extrapolating from the 1986 study, one might expect a low incidence of asthma.

So why did I read in May this year that the prevalence of asthma in Bermuda is as high as 1:5 children and 1:10 adults, one of the highest in the world?

The Bermuda Health Council last surveyed adult health in 2011. They reported:

Overall, 15.2% of respondents had asthma at some time and 9.8% said they currently had asthma. Women (11.1%) were slightly more likely to have asthma than men (8.2%). Asian and other races (14.6%), single parent households (16.4%), and those with a household income less than $60,000 (14.8%) were more likely to currently have asthma. Those aged 65 and over were slightly less likely to have asthma than other age groups (8.5%).

Last year (2012) around 2000 people were treated for asthma at the Emergency Department of the local hospital – that excludes visitors to the island. This compares with UK figures of 1:11 children and 1:12 adults (http://asthma.org.uk ). Why?

I have just spend half a day reading research papers on asthma in sub-tropical climates, only to conclude “it’s complicated”. Clearly Bermuda does not have high levels of atmospheric pollution, at least not outdoors, but it does have high humidity and this is linked with increase in moulds and dust mites (http://www.lung.org/healthy-air/home/resources/dust-mites-and-dust.html )

It is recommended to minimize dust mites one should keep internal humidity to 50% or less. Bermuda humidity is never below 70% and often above 80% – hence the demand for air conditioners and dehumidifiers is high.

So humidity, mold and dust mites account for much of the high prevalence. But we must not forget the cockroach! Calling them “Palmetto Bugs”, as the Bermudians do, makes them seem more like friendly beetles, but their droppings contain allergens and they love warm places, especially if they can find some food crumbs. If that doesn’t trigger your obsessive cleaning then nothing will.

World Asthma day this year was May 7th and Open Airways, the asthma charity in bermuda, were giving away pillows, spacers and microfibre cleaning cloths to encourage chemical-free cleaning. Next World Asthma Day is May 8th 2014.

So, back to asthma: is there a bottom line?
Should people with asthma come to Bermuda?

Well, the prevalence has apparently “tumbled by a record 76%”
(http://www.royalgazette.com/article/20130507/NEWS06/705079966 ) – Don’t you love journalism – no reference, no figures, no timescale, just believe it!

But some people would have you warned away: http://www.bermudasucks.com/forum/general-discussion/asthma-and-bermuda-what-you-need-to-know-before-moving/
(“Bermuda-sucks” is an interesting site for an alternative view, maybe I’ll return to it in a later blog)

For short term, it would seem sensible to bring spare medication, have full travel insurance and be aware of your environment.
For those coming to reside then I would suggest a visit first, discussion with your specialist and lots of online reading in order to get a balanced view.
(disclaimer: I am not giving medical advice here, this article merely relates a few facts and my own meanderings)