What is pityriasis rosea?
Pityriasis rosea it is a characteristic skin rash
thought to be caused by a virus.
It commonly occurs in young
adults (especially aged 15-30),
but might occur at any age. It is
not considered to be contagious.
What are the symptoms?
The herald patch
The rash usually starts with a
large spot on the trunk, called
a herald patch because it heralds
the onset of a widespread
rash 1-2 weeks later. This herald
patch is often mistaken for ringworm.
About one in five people
with pityriasis rosea will not
have a herald patch.
The rash
In a few days the spots break
out over the body, covering the
trunk and upper arm (in a
T-shirt distribution), and the
upper legs. Rarely, the rash can
cover the neck and face. The spots become oval patches
(about 1-2cm) of salmon-red or
copper-coloured skin with scaly
margins.
The rash is arranged along the
skin creases (called cleavage
lines) to give the appearance of a
Christmas tree, especially on the
back of the body.
Other symptoms
Patients are not ill, although
there may be some minor discomfort
from itching. Some
patients have no itching at all,
while others can have considerable
itching.
What are the risks?
There are no risks attached to
pityriasis rosea, but you should
visit your doctor to make sure
you do not have another similar
skin disorder, such as ringworm. 
No scarring will result from
the skin rash unless there is a
complicating infection. Second
attacks are rare.
What are the differential
diagnoses?
Apart from confusing the herald
patch with ringworm, two conditions
can cause confusion.
One is a type of psoriasis called
guttate psoriasis, which is an
acute rash of sudden onset. The
other is a drug eruption, which
may follow the intake of drugs
used to treat rheumatoid arthritis
or hypertension.
How long does the rash last?
Pityriasis rosea usually runs a
natural course of 4-10 weeks. It
disappears of its own accord.
There are no medicines or treatments
available to shorten this
course.
What is the treatment?
There is no special treatment for
pityriasis rosea. You should lead
your normal, active life. If possible,
expose the skin to moderate
amounts of sunlight because
this tends to lessen the rash, but
you must avoid sunburn. Otherwise,
ultraviolet light therapy
three times a week is helpful.
Bathe and shower as usual, but
use a mild soap such as Dove or
Neutrogena.
If itching is a bother, use a
soothing lotion or cream. Soothing
lotions include:
* Calamine lotion;
* Calamine lotion with 1%
phenol;
* Menthol 1% in aqueous
cream;
* Urea cream.
A soothing bath oil, such as QV
Bath Oil, can give relief and is
particularly useful for children.
If itching is severe, your doctor
will probably prescribe medication,
which may include a topical
corticosteroid (cortisone)
cream.
|
