Psoriatic arthritis

psoriatic arthritis

What is in this booklet?

This booklet aims to answer questions commonly asked by people who have psoriatic arthritis. Each section is a response to a different question. The first words (in italics) give the short answers to these questions but further information follows. Near the end of the booklet you will find some useful addresses as well as information on how to contact the Arthritis Research Campaign (arc).

What is psoriatic arthritis?

Psoriatic arthritis is inflammation in and around the joints in people who also have psoriasis.

There are 78 major joints in the body and psoriatic arthritis can affect any one of these. Usually, however, certain joints are more likely to be affected. Different patterns are found. Sometimes just one or two joints (such as a knee or ankle) are a problem but often several joints, both large and small and on both sides of the body, are involved. About a third of people with psoriatic arthritis also have a painful, stiff back or neck caused by inflammation in the spine. This is called spondylitis.

Psoriasis can affect the nails with pitting, discolouration and thickening. Sometimes the joint at the end of the finger or toe can also be inflamed.

There can be a sausage-like swelling of a finger or toe with psoriatic arthritis. This is called dactylitis and is caused by inflammation occurring simultaneously in joints and tendons. Painful heels can be caused by inflammation where gristle attaches to bone.

Psoriatic arthritis usually affects adults but occasionally children can develop the disease (see arc booklet ‘When Your Child Has Arthritis‘).

How does the doctor diagnose psoriatic arthritis?

Psoriatic arthritis is diagnosed based on what has happened to you and what is found on examination. There is no specific test for psoriatic arthritis.

Most doctors would require you to have psoriasis, or a history of psoriasis in a close relative, together with arthritis and inflammation in at least one joint. If several joints are affected the doctor would expect to find a pattern of joints involved which matches one of the patterns usually seen in psoriatic arthritis. Blood tests for rheumatoid arthritis are usually negative. However, in some cases it is difficult to distinguish between psoriatic arthritis and rheumatoid arthritis. In these cases doctors will consider features such as the pattern of arthritis (which joints are affected) and other clinical changes (see ‘What is psoriatic arthritis?’) to distinguish between the two conditions.

Can psoriatic arthritis attack other organs of the body?

Usually, no.

Apart from the skin, nails and joints no other major organs are involved. An itchy, red eye due to conjunctivitis is more common in people with psoriatic arthritis and some people occasionally develop a painful, red eye caused by inflammation around the pupil of the eye, which is called iritis or uveitis. Anaemia (a shortage of red blood cells) may also be found but this is the result of long-term inflammation and is not a specific feature of psoriatic arthritis.

How common is psoriatic arthritis?

Psoriatic arthritis is not common.

About 1 in 50 people have psoriasis. Of these about 1 in 14 will develop psoriatic arthritis. Other forms of arthritis, such as osteoarthritis and rheumatoid arthritis, may also occur in people who have psoriasis but this booklet deals only with the particular form of arthritis that is associated with psoriasis. For more information on these other types of arthritis, see the arc booklets ‘Osteoarthritis’ and ‘Rheumatoid Arthritis’.

What is the cause?

The exact cause is unknown.

Current research suggests that something (perhaps an infection) acts as a trigger in people who are susceptible to this arthritis because of their genetic make-up. Psoriasis often runs in families, as does arthritis. A particular combination of genes makes some people more likely to get psoriasis and psoriatic arthritis. No specific infection has been found – it may be that a variety of infections (including bacteria that live in patches of psoriasis) can trigger the disease.

Will my children develop psoriatic arthritis?

Your children are at low risk of developing psoriatic arthritis but they will be more likely than the next person to get the disease.

Both psoriasis and psoriatic arthritis run in families. Sometimes other diseases such as inflammation of the bowel (Crohn’s disease and ulcerative colitis), stiffening of the spine (ankylosing spondylitis) and severe eye inflammation (iritis or uveitis) also run in the same family. The link is genetic but the chance of passing it on is low.

What links the skin and the joints in psoriatic arthritis?

The link is probably genetic but many treatments help both the skin and the joints at the same time.

Some people find that when their psoriasis is bad their arthritis is also bad and as one improves, so does the other. It is possible that bacteria in the skin disease trigger the inflammation in the joints – see ‘What is the cause?’ Most people develop psoriasis before arthritis but about 1 in 10 develop the arthritis first.

What sorts of treatment are available?

Treatment is given by a team of health workers (usually a rheumatology team) including doctors, nurses, physiotherapists, occupational therapists and podiatrists.

The doctor (either your GP or specialist) will probably be the first to diagnose your condition. S/he will probably also be the person who refers you to other members of the team and starts treatment with drugs (see below). The other members of the health team play an important role in your education about the disease, as well as providing monitoring and treatment within their own specialist areas. Their advice and treatments are invaluable because tablets are not the only way of combating psoriatic arthritis. Although the roles of the rheumatology team members overlap, a general guide to their specialist areas is shown below:

The nurse practitioner will provide information and guidance about your disease and the drugs you take but will also give advice and information relating to your home and personal situation.

The physiotherapist will assist you with physical therapies (use of heat, cold, and other therapies to help your joints) and will advise on helpful exercises. It is important to maintain the mobility of your joints as well as maintaining the strength in your muscles. Exercise therapy is particularly important in people with spinal inflammation (spondylitis). (See arc leaflet ‘Physiotherapy and Arthritis’.)

The occupational therapist has an important role in advising you on how to protect your joints from further damage and may give you splints to wear – particularly on your wrist and hands. S/he will also assess whether equipment is needed to help you cope at home.

The podiatrist (foot specialist) will assess your need for regular foot care and whether specially made insoles will be of help to you. This specialist will also advise on footwear and where you can buy appropriate shoes.

The hospital pharmacist will probably offer extra advice on the tablets prescribed. Many of the tablets used for psoriatic arthritis are also used in other forms of arthritis, particularly rheumatoid arthritis. This can sometimes be confusing but remember that in both conditions the joints become inflamed and the tablets are used to control this inflammation. Information about the main types of tablets used is shown below.

What are anti-inflammatory drugs?

Anti-inflammatory drugs act by blocking the effects of the inflammation which occurs in the lining of your joints.

They can be very effective in controlling the pain and stiffness of arthritis. Usually you feel a benefit within hours of taking these drugs but the effect will only last for a few hours so the tablet has to be taken at regular intervals for the benefit to continue. Some people find that these tablets are of little help, and some people find that they help at first but the benefit begins to wear off after a few weeks. In this situation it sometimes helps to try a different anti-inflammatory drug – there are over 40 to try.

Examples of anti-inflammatory drugs


The main side-effect of anti-inflammatory drugs is indigestion and, in some cases, they can cause a stomach ulcer. For this reason doctors recommend taking these tablets with or after food. You must tell a health professional (preferably a member of the rheumatology team) if you get indigestion while taking these drugs as something can be done to help this – either tablets which can help counteract the effect or a change to a milder anti-inflammatory drug.

What are disease-modifying drugs?

Disease-modifying drugs help by attacking the causes of the inflammation in the lining of the joints.

These drugs act quite differently from anti-inflammatory drugs and hopefully will stop your arthritis from getting worse. Unlike anti-inflammatory drugs they often take weeks before they start to have an effect on your joints. Therefore it is important to keep going with these tablets for several weeks even if you think they aren’t doing any good. Sometimes these drugs are given by injection because a suitable tablet is not available and because a greater amount of the drug can be given in this way.

Examples of disease-modifying drugs


It is important to realise that anti-inflammatory drugs can be taken along with disease-modifying drugs. In fact, it is sometimes necessary to give more than one disease-modifying drug, so you could end up taking several tablets a day. Not surprisingly some people feel sick after all these tablets but there are ways of preventing this such as taking your tablet with a meal (unless you are advised not to). The side-effects of disease-modifying drugs are more complex than with anti-inflammatory drugs and with almost all disease-modifying drugs you will need to have a regular blood test. The reason for the blood test is to allow your doctor to monitor the effects of the drug on your disease but also to check that the drug is not causing problems with your blood count (the number of blood cells) or affecting your liver and kidneys. To help this monitoring a ‘shared-care’ card is provided which is used to keep details of the drugs, their doses, and the results of blood tests. You should carry this card at all times.

Will steroids be used?

Steroids are often recommended as an injection to the inflamed joint or where the tendon attaches to bone.

In general, steroid tablets (such as prednisolone) are not used in this disease. However, small injections of steroid are often recommended for joints which are particularly troublesome and for the painful bony sites where ligaments and tendons become inflamed.

What sort of treatments are appropriate for my skin?

Treatment is initially with ointments but the more severe cases may require tablet treatment and light therapy.

Ointments and creams can be of five types:

  • Some ointments are tar based although it may not be obvious that they contain any tar.
  • Dithranol-based ointments and creams. These can burn normal skin, so careful instructions are issued for their use.
  • Sometimes an ointment or cream containing steroid is used.
  • Vitamin D ‘analogues’ such as Dovonex.
  • Retinoids.

Light therapy involves being exposed to high intensity ultraviolet light for short periods. This treatment has to be carried out in a hospital. Many of the disease-modifying drugs used for psoriatic arthritis will also help the skin disease and often dermatologists and rheumatologists work together in treating you.

Treatment of nail psoriasis is not usually helpful. Disfigurement is very noticeable to the person who suffers from it but fortunately less so to other people. Some people use nail varnish to help make it less noticeable.

How much rest and exercise should I take?

Inflammation can cause generalised tiredness and you may find you need to take more rests than usual. On the other hand, inflammation also causes muscle weakness and stiff joints and it is very important to keep exercising the joints to stop them becoming weaker and losing function.

It is hard to generalise on this question – no two people are the same. However, the statement above is true for most conditions where there is inflammation. It is a question of finding the right balance for yourself but remember not to neglect either rest or exercise when you are trying to help your disease.

Are any special diets recommended?

Many diets have been suggested for psoriatic arthritis but none have been found to be very effective.

A number of books recommend different diets for people with arthritis. However, some books contradict each other. Some may even recommend stopping your tablets in order to try the diet. Don’t do this without telling your doctor. Sometimes the diet can help reduce the need to take some of your tablets but unfortunately this is rare. Cod liver oil and other marine (sea water) fish oils may reduce the amount of anti-inflammatory drugs needed to control joint inflammation and therefore may be worth a try.

If you are overweight, you need to follow a weight-reducing diet because of the extra strain this puts on your leg joints and back.

For more information, see arc booklets ‘Diet and Arthritis‘ and ‘Complementary Therapies and Arthritis‘.

Should I give up work?

The answer to this question depends on your arthritis, your age and your job.

People who work – both in physical jobs and offices – will have difficulties if they develop arthritis, but the problem may not be as serious as it first appears. Difficulties with work are recognised by the Benefits Agency and the Department of Employment. Work assessment and retraining can be arranged by your local Disability Service Team, which can be contacted through the Job Centre. If you are disabled due to arthritis and wish to carry on working then the local Employment Medical Advisory Service can also help keep you in work by providing equipment which is needed to make it easier for you to do your job. Advice on how to contact these agencies can be given by a health professional such as an occupational therapist or at a Citizens Advice Bureau.

Where do I get advice on benefits?

Advice on benefits is available from a number of places including the local Department of Social Services office and the Citizens Advice Bureaux.

Benefits are available to provide financial support to people who, due to their illness and disability, are unable to work and have difficulty with mobility. You should discuss these with a health or social worker or someone from the Citizens Advice Bureau.

Will this disease affect my sex life or my chances of having children?

Your chances of having children will not be affected. Painful joints can be a problem and interfere with your sex life but there are ways round this.

Psoriatic arthritis will not in itself affect your chances of having children or carrying a successful pregnancy. For a woman who becomes pregnant, the arthritis often improves during the pregnancy. However, the arthritis may worsen after the child has been born. It is also worth remembering that looking after small babies is hard work and even harder if you have painful joints. Would-be mothers with psoriatic arthritis should therefore try to get plenty of help with childcare.

Sexual intercourse may be painful, particularly for a woman whose hips are affected. Using different positions can help. It may help to discuss this with a member of the rheumatology team or ask for arc booklet ‘Sexuality and Arthritis’.

Some of the drug treatment given for psoriatic arthritis should be avoided when starting a family. For instance, sulphasalazine can cause a low sperm count (this is not permanent) and methotrexate should not be taken by couples trying to conceive. If you are considering starting a family you should discuss your drug treatment with your doctor.

Will an operation be necessary?

Sometimes operations are necessary to repair damaged tendons and, in some more severe cases, to replace worn-out joints.

Operations are not often needed in psoriatic arthritis. Very occasionally a tendon may become damaged and need surgical repair. Sometimes, after many years of disease, a joint worn out by inflammation is best treated by replacement with an artificial joint. There is no reason why this should be a problem in psoriatic arthritis compared to any other arthritis. However, if the psoriasis is bad in the skin around the affected joint some surgeons like to give a course of antibiotic tablets to cover the operation. Sometimes in people with psoriatic arthritis psoriasis can occur along the scar of the operation – this can be treated in the normal way.

What will the future hold for me?

Psoriatic arthritis can vary from a simple condition to a long-term problem requiring complicated treatment.

Everyone is different. Therefore it is impossible to offer specific advice on what you should expect. Most people with this condition will be on long-term treatment with anti-inflammatory and disease-modifying drugs. Generally, people with psoriatic arthritis are less disabled than people with rheumatoid arthritis. If your arthritis progresses it may, as mentioned above, cause problems with your work. See the section ‘Should I give up work?’

Are any self-help groups available?


Arthritis Care and Young Arthritis Care both provide support, information and help and organise meetings locally (national contact addresses given below). Arthritis Care also arrange courses for young people to help with self-management.

Recently groups such as the Psoriatic Arthropathy Alliance (PAA) and Psoriasis Scotland Arthritis Link Volunteers (PSALV) have been formed specifically for those affected by psoriatic arthritis. Such groups can offer informative literature and may organise meetings addressed by specialists in psoriatic arthritis.

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