What is psoriasis?
Psoriasis is a common
skin condition which commonly develops as patches ('plaques') of red,
scaly skin. There is no 'once and for all' cure for psoriasis.
Treatment aims to clear the rash as much as possible. However, as
psoriasis tends to come and go, you may need courses of treatment on
and off throughout your life. There are various treatments. There is no
'best buy' that suits everybody. The treatment advised by your doctor
may depend on the severity, location and type of psoriasis. Also, one
treatment may work well in one person, but not in another.
This
leaflet is just about creams and ointments that contain drugs related
to vitamin D (vitamin D analogues) that are used to treat psoriasis.
Three vitamin D analogues are currently available in the UK -
calcipotriol, calcitriol and tacalcitrol. There are separate leaflets
on psoriasis in general, and on the other common topical treatments for
psoriasis - dithranol, coal tar, steroid creams and tazarotene.
Some notes about the Vitamin D analogues
Vitamin
D analogues are popular and often work well to clear plaque psoriasis.
They are easy to use, are less messy, and have less of a smell than
coal tar or dithranol creams and ointments which are also commonly used
treatments. They seem to work by slowing the rate that skin cells
divide. (The skin cells in patches of psoriasis divide faster than
normal.)
Follow the instructions carefully that come with the
brand you are prescribed. Also, persevere with the treatment as success
often takes several weeks. The following are some general points that
aim to complement - not to replace - the instructions that come with
the preparation that you are prescribed.
Calcipotriol
Calcipotriol cream or ointment
has become one of the most commonly used 'first-line' treatments for
plaque psoriasis - the common form of psoriasis. There is also a scalp
preparation of calcipotriol which is used to treat scalp psoriasis.
The
cream or ointment is commonly applied once or twice daily. There is
usually an improvement in the skin within two weeks, and improvement
then usually continues for at least eight weeks. At this point, the
psoriasis is cleared in some patients, but in others there is just an
improvement which plateaus and the psoriasis does not clear completely.
Any improvement can usually be maintained by continuing treatment.
Generally,
calcipotriol is thought to be safe, provided that you follow the
manufacturer's instructions. (There are some cautions mentioned below.)
The instructions include that you should not exceed the maximum dose.
This is 100g or cream or ointment per week for adults, 75g per week for
children over 12, and 50g per week for children of 6-12. It is not
recommended for children under six years old. If you are using a scalp
preparation, the maximum use is 60ml of scalp lotion weekly.
But note - if you are using calcipotriol as a cream of ointment for your body, and
a scalp lotion, the total dose needs to be balanced between the two. In
this situation, the maximum amount of each is less than stated above.
You should follow the instructions given by your doctor.
Wash your hands after applying to avoid inadvertent transfer to other body areas.
Calcipotriol
may cause skin irritation which may cause redness, soreness or itch in
around 1 in 5 users. Any skin irritation that does develop usually
settles, but sometimes a break in treatment is needed. Occasionally,
treatment needs to be stopped because of skin irritation. However,
because of the risk of skin irritation, you should not use calcipotriol
on the face and flexures (skin creases such as the front of elbows,
behind knees, armpits, groins, etc).
There is little experience
of using calcipotriol in pregnant women. Therefore, the manufacturer
advises that you should not use calcipotriol when you are pregnant
(which also means if you are trying for a baby). It is also probably
best not to use it when breastfeeding. Also, people with calcium
metabolism disorders should not use calcipotriol as there is a risk of
causing a high blood level of calcium.
Rarely, psoriasis has
been reported to get worse in a few people after using calcipotriol.
There have also been isolated reports of more serious side-effects when
a large quantity of calcipotriol was used by people with the more
severe forms of psoriasis - erythrodermic and pustular psoriasis.
Therefore, it should be used by people with the more severe forms of
psoriasis - erythrodemic and pustular psoriasis - only under the close
supervision of a specialist.
Calcitriol and tacalcitol
Calcitriol and
tacalcitol ointments contain different vitamin D analogues to
calcipotriol. An advantage of calcitriol and tacalcitol is that they
are less irritant than calcipotriol. Therefore, one or other may be
suitable for use on the face and flexures if advised by your doctor.
You should not use more than 30g calcitriol ointment per day and it
should not be applied to more than a third of your body surface each
day. You should not use more than 10g tacalcitol ointment per day.
Calcitriol
and tacalcitol have not been licensed in children and have not been
adequately assessed for use during pregnancy. So, do not use when you
are pregnant or trying for a baby. You should not use either if you are
breastfeeding.
Combination treatments
A vitamin D analogue
is sometimes used in combination with another treatment for psoriasis
if either treatment alone is not sufficient. For example, an ointment
that contains calcipotriol combined with a steroid may be prescribed
when calcipotriol alone has not worked very well. However, it is not
usually wise to use a steroid long-term. Therefore, one treatment
strategy that is sometimes used is to use calcipotriol combined with a
steroid for four weeks, alternating with calcipotriol alone for four
weeks.
Another example is that some people continue to use a
vitamin D analogue in addition to light therapy (UVB or PUVA) which is
sometimes used to treat psoriasis.
Further sources of information
Psoriasis Association
Dick Coles House, 2 Queensbridge, Bedford Road, Northampton NN4 7BF
Tel (helpline): 0845 6 760 076
Web: www.psoriasis-association.org.uk
References
