Psoriasis en gouttes

What is guttate psoriasis?

Although it has the name 'psoriasis', guttate psoriasis is almost a completely different condition to the usual psoriasis. It is a skin condition that comes on quickly, usually a few weeks after a throat infection. Some medications can also cause it.

• For some reason a group A beta-haemolytic streptococcus infection, which can cause a really sore throat, sometimes causes a skin reaction.

• It's thought to be caused by your immune system going into 'overdrive' and accidentally reacting to your own skin.

• The throat infection is found in about 80% of cases.

• No one can quite figure out why this happens but some people seem to be more prone to it than others. It might be to do with your genetic make-up.

• In this way it's similar to the way a throat infection can lead to rhumatismale aiguë.

Can anything else cause guttate psoriasis?

Rarely some medications can cause guttate psoriasis, particularly lithium (used for mental health problems) and beta-blockers (used in heart conditions).

The word 'gutta' means 'drop' in Latin so that's where the name guttate psoriasis comes from: it can look like tiny pink drops have been scattered on the person's body. They are usually slightly raised, with a thin white scale. They don't hurt, but they can be a bit itchy.

Guttate psoriasis hands

© Mohammad2018, CC BY-SA 4.0, via Wikimedia Commons

The above image shows guttate psoriasis on the back of someone's hands:

• The spots come on pretty quickly, over just a day or two.

• They usually cover the chest, tummy, upper arms and thighs.

• Usually the palms of the hands and soles of the feet are not affected.

• It only occasionally affects your head and face.

• They are slightly raised, light pink skin marks that might have a white scale to their surface.

Does guttate psoriasis make you feel ill?

• Usually the appearance of the spots is the worst thing about it.

• It doesn't usually make you feel ill or feverish.

• The spots are not usually painful, but they can be a tiny bit itchy (only a little bit though).

• You can imagine that coming up in spots all over your body in just a few days can be pretty distressing: a lot of people are quite upset when they see their doctor.

• The good news is, guttate psoriasis typically fades by itself within a few weeks to a few months.

• It doesn't necessarily need treating unless it's really bothering the person. No particular treatment option has been shown to work better than others.

• A GP may prescribe a mild steroid cream if the lesions are itchy - although in practice it is quite hard to spread cream over such a large area of the body. It is worth nourishing the skin with simple moisturisers.

• Although it is related to a bacterial throat infection, giving antibiotics doesn't actually speed up the spots going away.

• A dermatologist may use 'light therapy' which is where they beam UV light at you in a special box (a bit like tanning!). This is a specialised treatment that isn't available in all hospitals. It can help to clear up the guttate psoriasis a bit quicker than otherwise.

There aren't any particular tests for guttate psoriasis.

It's diagnosed by the way it looks and also by finding out if there has been a throat infection a few weeks before. Occasionally a blood test can be used to detect the streptococcus germ (bacterium): this is called an anti-streptolysin antibody assay.

A skin biopsy is not usually needed. If it isn't quite clear what the skin condition is, a specialist skin doctor (dermatologist) might use a small microscope (a dermatoscope) to look at it more closely.

Can guttate psoriasis be confused with anything else?

• There are other conditions that give similar skin problems.

• Pityriasis rosé can look a bit like guttate psoriasis, but doesn't follow a throat infection.

• Pityriasis lichenoides can resemble guttate psoriasis, but again doesn't follow a throat infection. And the lesions look a bit different to guttate psoriasis.

Voir également la brochure séparée sur Skin Rashes.

Who is affected by guttate psoriasis?

• Usually young people get guttate psoriasis, in their teens or twenties. Men and women are affected equally.

• It seems to occur all over the world.

• No one really quite knows how common it is. In general, a GP in the UK would have heard of it and probably know how to diagnose it, but they may not have seen a case themselves for many years.

• In nearly two thirds of people with guttate psoriasis, the spots clear up and never come back.

• Occasionally the spots turn into a more long-term type of psoriasis called plaque psoriasis. This can be treated with similar creams and light treatment.

• Once it's cleared, sometimes (but not very often) a second outbreak of guttate psoriasis happens. This could happen if the streptococcus bug is lurking in your tonsils.

• Thankfully the guttate psoriasis never properly scars, although sometimes it can leave tiny pale marks where it used to be: these should fade with time though.

Usually it comes and goes and then that's all there is to it. In about 80% of people the spots will fade in three weeks to three months and never come back. But in some people it carries on to be long-term plaque psoriasis. Sometimes you can get a second outbreak, particularly if the streptococcus germ (bacterium) is still in your throat or tonsils.