PSORIASIS AND THE SUN
Psoriasis is a skin condition which most usually takes the form of itchy red
patches which show fine silvery scales when scraped, rubbed or scratched. These
patches may appear on just a few areas of the body, or on the scalp, or they
may be very extensive. Psoriasis is uncomfortable and often embarrassing to
suffer, but it is never catching.
Many of those who have psoriasis find that sun much improves their skin's
appearance. For many the change is dramatic, with red scaly patches almost
disappearing altogether during summer months in a warm climate.
UVB
The benefit of sunshine for psoriasis sufferers comes from UVB, one of the
forms of ultraviolet light (UV) that comes from the sun. There are three forms:
UVA; UVB; and UVC. Short wavelength UVC is absorbed by the ozone layer of the
atmosphere and does not reach the earth's surface at all. The ultra-violet
light that does reach us is mainly long wavelength UVA with some intermediate
wavelength UVB, and it is the UVB rays which help psoriasis.
UVB starts the tanning process and it is this reddening effect immediately
after exposure to the sun that is the healing element in psoriasis. However too
much UVB is not a good thing because it burns. Even UVA is not harmless, and
too much of both can prematurely age the skin and increase risk of skin cancer,
so you really need to take care even if you do find that sunshine helps your
skin. You are at highest risk if you are fair- or red-haired and your skin does
not tan easily.
Because ultraviolet light is so effective for so many psoriasis sufferers,
it is often used in various artificial forms by doctors. Ultraviolet treatment
with a sunlamp is often given in hospitals for plaque psoriasis (the most
common type) and guttate psoriasis. In severe cases of psoriasis,
dermatologists may use a treatment known as PUVA - P for psoralens, plus UVA.
Psoralens are chemicals found in some plants which can make the skin respond to
UVA, the least dangerous form of UV light.
Treatment
If you have psoriasis, it is important that you visit your doctor regularly
to make sure your treatment is effective and to change it if necessary. No cure
yet exists for psoriasis so the main aim of treatment is to keep the condition
under control, usually by reducing the rate of proliferation of skin cells.
Most people can be treated by their GPs with topical treatments.
Topical therapy
Tar products
These are the oldest treatments for psoriasis and include gels, creams,
shampoos and bath preparations. Tar products can be effective but are limited
by being smelly and messy. Most will stain skin and clothes which may mean that
people do not use them as often as they should.
Topical steroids
These agents are effective in psoriasis and are clean, non-irritant and
quick-acting. Creams, ointments and scalp preparations are available. However,
topical steroids are not recommended for prolonged use because they can cause
thinning of the skin leading to bruising and other unwanted effects.
Dithranol
Dithranol is effective when used correctly and may be used long term. It is
normally recommended as a "short contact" procedure in which
dithranol is applied daily to plaques and removed after half an hour. The
process can be time-consuming since great care must be taken when applying the
dithranol and washing it off. This level of care is necessary because dithranol
can cause irritation to the skin. For this reason it is not recommended for the
face, flexures and genital region. Dithranol oxidises in the air to a
purple-brown dye which can stain skin and clothes.
Vitamin D analogues
The first available of these analogues, Dovonex (calcipotriol), is one of the
more recent treatments for psoriasis. It is available as a scalp solution, and
as both cream and ointment formulations. It has advantages over many other
treatments because it is odourless, non-staining and convenient to use as well
as effective. Skin irritation may occur in some people but this is normally
mild and only causes a few to stop treatment.
Other therapies
Other therapies may be used in more extensive or incapacitating psoriasis
under the supervision of a hospital dermatologist. These include light therapy
(PUVA or UVB) and systemic therapies including methotrexate, etretinate and
cyclosporin. Whilst these therapies are often very effective they unfortunately
can have severe or unpleasant side-effects.
Embarassment
Psoriasis sufferers often face a dilemma. They have heard that the sun is
good for their condition, yet are loath to reveal any more of their skin than
they are absolutely obliged to. You are not alone if you are one of those who
wear polo necks, long sleeves, and trousers or leggings, even on the hottest
summer days, never sunbathe on the beach, and never venture into the water.
Sadly, of course, it means you miss out on a lot of fun. Most people feel
they look at their best in the summer, and when you feel good you do look good.
But if you spend summer desperately trying to cover up psoriasis, that does not
do much for confidence at all. Often the more self-conscious about your
psoriasis you are and the more depressed it makes you, the worse it is actually
likely to be.
Covering up through embarrassment also means that you may miss out on all
sorts of activities that bring families or friends together, such as taking
children swimming, and playing sports in the local park or on the beach. All in
all, it means summer is not much fun.
So, if you are someone whose skin might benefit from sunlight, it could well
be worth taking the plunge, swallowing your pride, and letting the sun get at
your skin.
If sun does not do you any good, at least you will have given it a go and
can concentrate your efforts on finding cool stylish ways to stay covered.
Safer sunning
Whether sunlight, real or artificial, will help you may depend on many
things, such as the type of your psoriasis, your age, the treatment you may
already have had for it, etc. Take some advice from your doctor about whether
you should try sunlight. If your skin does react well to the sun, follow these
guidelines to stay safe.
The general good advice is to avoid being out in hot sun between 11a.m. and
2 p.m. But as time of day is not always the best indicator of the sun's
strength (owing to differences in longitude and latitude in different parts of
the world), it might make even better sense to check the power of the sun by
the shadow it throws. If your shadow is shorter than you are, the sun is more
likely to be burning hot.
Remember that shade does not give you 100 per cent protection. Water, sand
and concrete can all reflect sunlight and increase your chances of burning. And
sunlight can penetrate glass, cloud, water and fine hosiery such as tights.
Use the sunscreen that suits your skin but do not just apply it once and
forget about it. Re-apply every few hours or more often if you go swimming and
especially if you towel yourself dry afterwards.
Loose fitting clothing is better protection against the sun than tight
clothing, and dark colours are more protective than light ones.
Choosing a sunscreen
Sunscreens nowadays have sun protection factors (SPF) which measure
protection against UVB. The sun protection factor is based on your own
judgement of how long you can stay in the sun without burning. If you can sit
out for 10 minutes without burning an SPF of 15 will give you 15 times as much,
i.e. 150 minutes of suntanning without worrying about burning.
As your suntan develops you need less protection, so you can start to reduce
your sunscreen SPF without burning. SPF 15 and above are high protection, 7 to
14 are medium and 2 to 6 low.
There is now also a rating system for UVA, with three or four stars showing
that a particular preparation offers high protection against UVA. If you have a
skin which needs a high SPF against UVB, you will probably benefit from a high
star rating for UVA too.
Remember that it is very important not to burn, as this can increase your
risk of skin cancer.
Sunbeds and sunlamps
If you want to use a sunbed or sunlamp, do talk to your doctor, preferably a
specialist, first. Sunbeds are not necessarily safer than the sun, although
many people may mistakenly believe they are. They are only likely to be of any
help if your skin also benefits from natural sunlight.
Be sure that operators at any solarium you choose to go to are properly
trained and understand their equipment, which should meet industry standards
and have regular checks for safety. Check which wavelengths (UVA or UVA and
UVB) are emitted. A sunbed that emits only UVA will not help you.
Always wear goggles if using a sunbed, and do not stay on it for longer than
the specified time. Using a sunbed does not automatically mean that you
increase your protection against getting burned by the sun. This will only
happen if you develop a tan. If, after a few sessions, you do not start to
develop a tan from a sunbed, you are still at high risk of burning in the sun.
If you use a sunlamp, particularly if you buy one for your use at home, take
advice from your specialist on which type to buy and follow the manufacturer's
instructions to the letter. It is the UVB rays that you will need to use and
you have to be extremely careful to ensure these do not burn your skin.
Useful organisations
The Psoriasis Association
7 Milton Street
Northampton NN2 7JG
 01604 711129
The National Eczema Society
163 Eversholt Street
London NW1 1BU
01207-388 4097
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