A course of dithranol ointment or cream often works well to clear
plaque psoriasis. One drawback is that it can irritate skin and stain
clothing. These effects can be minimised if dithranol is used for a
short period each day and the strength is gradually increased to the
strongest tolerated. Follow the instructions carefully that come with
the preparation you are prescribed for the best chance of success and
minimal problems.
What is dithranol and short contact dithranol treatment?
Dithranol is a drug that has been used in the treatment of psoriasis
for over 50 years. There are various ointments and creams that contain
different strengths of dithranol. Dithranol is usually a safe treatment
and will clear psoriatic plaques in many people with psoriasis.
As
a rule, dithranol is only used to treat the classical plaques (larger
patches) of psoriasis. It is not usually suitable for widespread small
patches of psoriasis that some people develop. Also, it should not be
used in the skin creases or flexures (front of elbows, behind knees,
armpits, groins, etc) or on the face unless supervised by a specialist.
This is because of the risk of irritating the skin in the skin creases
and irritating the eyes with dithranol.
Dithranol can irritate
if it comes into contact with normal skin around treated patches of
psoriasis. It can also stain clothing and fabrics that come into
contact with it. These problems can be minimised if dithranol is used
for a short period every day ('short contact') and the strength is
gradually increased so that the skin becomes used to the treatment.
How to use dithranol for short contact treatment
Follow the instructions given by your doctor carefully, and on the
packet of the preparation that you are prescribed. Also, persevere with
the treatment as success often takes several weeks. The instructions
may include the following:
- Wear plastic disposable gloves when applying dithranol cream or ointment. Wash hands thoroughly after applying dithranol.
- Apply only to the plaques of psoriasis. Avoid putting it on normal
skin. For creams, apply sparingly, rub in well and wipe off any excess.
For ointments, apply sparingly.
- Avoid getting any in or near the eyes. If eye irritation occurs wash thoroughly with water and if it persists, see your doctor.
- Leave the cream or ointment on for as long as directed by your
doctor. For short contact treatment, this may be anything from 5-60
minutes. Then wash it off.
- When washing off, just use cool water (below 30C) without soap or
detergent. Hot water or soap may cause increased staining of the skin
by the dithranol. You can use hot water and soap to wash after the
cream or ointment has been rinsed off.
A common treatment plan is to start with 0.1% dithranol. If
there is no irritation then apply daily as directed (often for about 30
minutes each day) for a few days. The strength is then increased to a
0.25% preparation which is continued for a further few days before
moving on to a higher strength, etc. The aim is to gradually build up
the strength (the % concentration) to the strongest preparation you can
tolerate. The strongest of the brands that can be prescribed is 3%.
However, hospital skin departments (dermatology departments) sometimes
use even higher strengths in some severe cases.
If irritation or
burning occurs, stop using dithranol and apply a moisturiser until the
skin has settled. Then start again at a lower strength. Some people are
more sensitive to the irritating and burning effects than others. So,
different people end up using different strengths.
Carry on with
the treatment until the treated skin feels flat and smooth like the
nearby normal skin. Any staining of the skin will clear, usually in
about two weeks. If you have problems with skin irritation, or if there
is no improvement after three weeks at the highest strength you can
tolerate, then see your doctor for advice.
Dithranol can stain
Dithranol stains normal skin a brownish colour. This is temporary and
will gradually fade. It may also stain clothes, sheets, furnishings,
etc, if they come into contact with dithranol. This staining can be
permanent. So, when using dithranol, wear old clothes that you don't
mind if they become stained.
Baths may also be stained. If
possible, have a shower rather than a bath after using dithranol
treatment. If you have a bath, clean it immediately with detergent. A
little vinegar added to rinse water helps to reduce staining.
If staining of the skin occurs in the centre of the plaques of psoriasis, this means the psoriasis is starting to clear.
How safe is dithranol?
Although during
treatment dithranol may irritate or slightly burn normal skin, and may
stain skin or clothes, it is generally a safe treatment. It has been
used for many years and, if used properly, is not known to cause any
long term side-effects or problems.
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
© EMIS and PiP 2008 Updated: 5 Feb 2008
