What is psoriasis?

Psoriasis is a non-contagious skin disorder that is usually evident on the skin as red patches with raised silvery scales and on the scalp as severe dandruff.

What causes psoriasis?

It is not known what causes psoriasis. It is thought that the abnormal cell growth that characterises psoriasis has a genetic origin operating through the immune system of the body. A normal skin cell matures in 28 to 30 days. In psoriasis, skin cell production is increased 10-fold, the immature cells sticking together causing the thick scales of "common psoriasis".

There is a family pattern in some psoriasis cases.

What can trigger psoriasis?

The following can trigger an onset or aggravate the disorder:

• skin injury - including severe sunburn
• infections
• stress
• certain medications
• alcohol
• smoking
• hormonal changes.

Who gets psoriasis?

Psoriasis affects men and women in equal numbers and may appear for the first time at any age. Up to 5% of the population may be affected by psoriasis.

Does psoriasis affect general health?

Usually the answer is no; however, up to one person in 10 with psoriasis can get joint involvement - with a degree of arthritis (psoriatic arthritis) affecting the back or small joints of the body. If psoriasis is severe and covers large areas of the body there can be other potentially severe problems.

Do nerves affect psoriasis?

Yes, a sudden severe shock can start psoriasis for the first time and also can cause any existing psoriasis to flare. This can make the person with the psoriasis more aware and concerned about the skin problem.

How is psoriasis diagnosed?

Dermatologists diagnose psoriasis by examining the skin and noting specific characteristics of the lesions (patches).

How is psoriasis treated?

The dermatologist (skin specialist) will design a personalised treatment plan that takes into account a person's overall medical condition, age, lifestyle, severity, duration of the psoriasis and expectations of treatment. Various treatments, combinations of treatments and many visits to the dermatologists may be necessary before the psoriasis is controlled.

Types of treatment for psoriasis

The types of treatment available are listed below. Choosing the right one for you, your doctor must take into account your previous response to treatments:

• ointments
• moisturisers
• de-scalers
• ultraviolet light therapy, eg, PUVA, UVB and narrowband UVB
• oral medication.

How long will psoriasis last?

There is no way of knowing in any particular case whether your psoriasis will persist for a long time or whether it will go away on it's own. Often it does clear up but it is impossible to predict how long it will take or how long the remission will last.

Is there a cure for psoriasis?

Although medical scientists know much about the cellular changes that occur and have identified many triggers, permanent cures are not yet possible. In many cases, psoriasis is controlled or improved by treating the visible effects rather than the basic cause.

A great variety of treatments exist but some are cosmetically unacceptable or difficult to use, while others are in themselves toxic and have side effects.

Does psoriasis affect life and work?

Most people with psoriasis find it a burden and a nuisance, but generally they are not stopped from enjoying life and doing their usual work.

Orignal material from the Psoriasis Association of New Zealand, with text kindly reviewed by Dr Nicholas Birchall, Dermatologist, Auckland. Edited by everybody, Feb 2005.