Pityriasis rosea

What is pityriasis rosea?

This is a common condition but many people have never heard of it because it's transient and rarely does much harm in the long run.

Pityriasis rosea is a skin disorder that appears as a rash. It's most common between the ages of ten and 35, and may last from a few weeks to several months. The cause isn't known, but a viral infection is suspected (though it doesn't seem to be contagious).

Symptoms

The rash typically starts with what's known as a 'herald' or 'mother' patch. This is a single area of pinkish scaling that usually appears on the chest or back, and is sometimes mistaken for the fungal condition ringworm. Soon after (a week or so), more pink patches will develop - and these may spread out to the arms and legs, and sometimes the head and face. It never affects the palms and soles, so if you have a rash there you can rule out pityriasis rosea.

Unfortunately, there's rarely much of a consistent pattern - the spots are different shapes and sizes. But although the patches may appear random they do sometimes seem to form a pattern on the back like the branches of a tree.

There may be no other symptoms, but in about half the cases there is itching. This can be quite intense, especially if the person gets hot. Some people also complain of tiredness and aching. Eventually the rash fades, but this may take many weeks and sometimes it returns for a while.

There aren't usually any permanent scars, although in people with darker skin there may be flat spots where pigmentation has increased (usually temporary).

Treatment and recovery

Pityriasis gets better on its own without specific treatments. The main focus for treatment is to control the itching, using a combination of creams, lotions and antihistamine tablets. Not only is itching unpleasant, but if the person scratches a lot there's a risk of damage to the skin, secondary infections and permanent skin changes.

Sometimes ultraviolet treatments and steroid creams are used, but only in extreme cases.

Anything that makes the person feel hot can make the rash and itching much worse (so avoid physical activity, hot baths).