Psoriatic Arthritis

What is Psoriatic Arthritis?
Psoriatic Arthritis (PSA) is an inflammatory arthritis associated with psoriasis.

It is a particular type of inflammatory arthritis that is medically called ‘sero-negative’. What that means is that the rheumatoid factor (the protein that is associated with rheumatoid arthritis) is not present in the blood (which is also known as, ‘serum’) thus it is called ‘sero-negative’, the negative meaning ‘not there’.

Who gets Psoriatic Arthritis?

Psoriatic arthritis affects men more than women and usually comes on in adulthood. It usually happens in people with psoriasis.

20-30% or people with psoriasis get psoriatic arthritis. In 15-20% of people the arthritis is there BEFORE the rash!
Rheumatoid arthritis affects about 1% of the population, whereas psoriatic arthritis affects about 0.1% of the population.

PSA can go into remission with treatments but usually relapses at some stage if the treatment is stopped.

At present there is no known cure for psoriatic arthritis but rather people need to be on medications lifelong. I do not know of any non-medical treatment to cure psoriatic arthritis! If I did, there would be no role for me as Rheumatologist…… 😉

Why do people get Psoriatic Arthritis?

We don’t really know why people get Psoriatic Arthritis. There is a strong association with Psoriasis, but, not everyone with Psoriasis gets Psoriatic Arthritis!

4-30% of people with Psoriasis get Psoriatic Arthritis

There is a strong relationship between the arthritis and having a family history of Psoriasis.

Lifestyle factors have been associated with the development of PSA, including obesity, and a history of trauma. Some patients who develop Psoriatic Arthritis report a preceding traumatic incident such as an injury, or a broken bone.

Its interesting, because Psoriasis can also occur in a site of a prior injury!

40% of people with PSA have a family history of Psoriasis.

How does Psoriatic Arthritis affect people?

Psoriatic arthritis (PSA) can affect one or a couple of joints and can be quite mild just needing anti-inflammatories as needed, or it can become quite severe affecting many joints. It can also affect the spine and this is something that is quite different to rheumatoid arthritis.

Psoriatic arthritis can create pain, swelling and inflammation in the joints, but also in the tendons.

This is known as ‘enthesitis’ and can result in what is known as a ‘sausage’ toe or finger (more medically known as ‘dactylitis’). Psoriatic arthritis can be very mild, but it can also be very severe.

A characteristic feature is the involvement of the nails, which can be quite pitted and in severe cases quite destroyed.

Each person is different and needs to be treated uniquely.

PSA can affect the small joints of the hands and feet, as well as the large joints such as the knees, hips and elbows and also the spine.

How do we diagnose Psoriatic Arthritis (PSA)?

Like most Rheumatological conditions, Psoriatic Arthritis is primarily a clinical diagnosis.

Usually people have a history of Psoriasis, in combination with arthritis appearing in key joints such as the distal inter-phalangeal joints (the joints at the end of the fingers) and/or the presence of dactylitis (the sausage shaped swollen digit).

Your Rheumatologists will do other investigations to assist in diagnosing you with Psoriatic Arthritis, by ruling out other causes of arthritis, and confirming a clinical diagnosis.

Common tests are Rheumatoid Factor and anti CCP antibodies – these are usually not present in PSA

Uric acid to rule out gout, and where appropriate immune and viral screens to rule out a possible infective or other autoimmune cause of arthritis.

Inflammatory markers such as ESR and CRP are done, but are not always high in psoriatic arthritis.

Xrays are usually done of hands and feet if they are involved, looking for damage in a characteristic pattern of psoriatic arthritis and a baseline chest Xray is usually done if therapy with DMARDs is considered.

Other imaging such as MRI’s of affected areas may be done if there is question about the diagnosis but are not always required. Other blood testing may be done at the discretion of your doctor to confirm or eliminate a possible diagnosis, in particular if the pattern of joint involvement is not exactly typical of psoriatic arthritis. This is where the skill and expertise of your Rheumatologist comes into play, as most things in life do not exactly fall into easy diagnostic ‘boxes’!

How do we treat Psoriatic Arthritis?
Psoriatic arthritis is treated according to its severity. Your Rheumatologist will guide you.

If there is one small joint mildly affected, then perhaps, anti-inflammatories as needed short term may be the order of the day, but if instead rather many joints are affected ongoingly, in particular large joints, then more long term treatment with DMARDs is required to keep people feeling comfortable. These decisions need to be made in conjunction with your treating Rheumatologist to make sure you get the best possible treatment.

Treatment is tailored to each person and their condition.

The medications that we have don’t cure the disease, but they control the effects of the disease so that people are more comfortable.

Untreated arthritis can be very painful, with a lot of stiffness that can make it very difficult to do every day activities including even dressing yourself. There are different avenues to look at treating psoriatic arthritis:

Drugs – DMARDs, Biologicals, anti-inflammatories and steroids



DMARDs are the mainstay of treatment and if they are not effective, there are Biological therapies for which some people may be eligible. Not everyone is eligible for these medications however. Anti-inflammatories and steroids tend to be used short term preferably due to risk of long term side effects if taken long term.

Diet and supplements can be used to further support your body in the treatment of your arthritis, but drugs are the best treatment to effectively control your symptoms.

For guidance regarding diet, drugs, and supplements to best support YOU, it is best to speak with your Rheumatologist. Diet and supplements are very personal and are an adjunct as part of an overall care plan for you and your arthritis. Not everyone may choose to make changes to their diet and lifestyle, and this is very individual for everybody. Some people are comfortable exploring making changes to food on their own, but it is supportive to get assistance from an expert in nutrition. There is a lot of information on the internet about food and arthritis and its hard to know what to follow. The best way to work it out is to experiment for yourself and see what makes a difference for you. Your Rheumatologist will tailor your medications for your particular condition.

What is the outcome for Psoriatic Arthritis?

Most people who have this arthritis usually have it until they pass over. This means that medications are usually recommended and needed for life.

The course of arthritis in each person is different and you can’t compare your disease and the outlook for your disease with anyone else, some will have mild disease and some will have more aggressive disease.

Anti-inflammatories can be used for the short term, but for the long term they are not ideal as they create many side effects with kidney and vascular issues.

The DMARD therapies have far fewer long-term side effects which is why we like to use them in Rheumatology!

Of course, taking a medication for life is not ideal and can be associated with long term side effects, but, we eat food all throughout the day, that goes through our mouth and we have no issues or concerns regarding that, and things such as sugar for example have definite long term effects on our body becoming additive with age, but we do not question these things… It’s interesting isn’t it that we have more of an aversion to taking medications than food, which has long been said to be our medicine, recorded since the time of Hippocrates!

Taking long term medication for Psoriatic Arthritis when needed is a responsible way of supporting your body.
Can Psoriatic Arthritis damage my joints?

Yes Psoriatic arthritis can damage the joints. On DMARD therapies when the disease is controlled, joints are less likely to be damaged.

Not everyone responds to DMARD therapies and this is important to note. The issue is not the failure of the DMARDS, but rather the aggressive nature of the underlying disease that is the issue.

Each person is unique in the severity of their disease, and the way that they respond to medications.
Take home messages about Psoriatic Arthritis

Psoriatic Arthritis is an inflammatory arthritis that can affect both small and large joints and sometimes the spine.

  • Its course is different in each person ranging from very mild to progressive and damaging.
  • Its stand out features are:
    • Tendon involvement,
    • Involvement of the distal interphalangeal joints,
    • Nail changes,
    • Dactylitis

It is associated with Psoriasis, but not everyone has psoriasis at the time of diagnosis!

  • There are a wide range of medications to treat it