Dr Stuart Myers

Psoriatic Arthritis

Psoriasis is a common red and scaly skin rash. It commonly occurs on the point of the elbows, knees and in the scalp.

         

It can occur anywhere on the body. It is quite different from Eczema.


7% of patients with psoriasis develop Psoriatic Arthritis a form of inflammatory (autoimmune)  arthritis. This incidence is much higher in patients with psoriatic nail changes.

    


It can affect any joint but particularly in the hands, feet, spine & sacroiliac joints.

The cause is unknown but may include: - Genetics  (40%)
                                                           - ? Trauma   

                                                           - ? Prior infection  eg Strep Throat
The peak age of onset is between 30 and 55 years.


The  symptoms  of Psoriatic arthritis may mimic others forms of arthritis associated with joint pain, swelling & stiffness.

Patients may also complain of:
- Enthesitis, development of pain and tenderness in the area where tendons or ligaments attach the bones and is commonly seen at the heel or plantar fascia.
- Low back pain due to the affect on sacroiliac joint
- Stiffness of joints either in the morning or after rest
- Fatigue


There are 5 Patterns of Psoriatic Arthritis:


- Symmetric arthritis  similar to rheumatoid arthritis  with  mild deformities.   
- Asymmetric arthritis   anywhere in the body, such as knee, hip, ankle or wrist - generally mild and usually responds to medical therapy.
- DIP joint like OA but with nail changes.
- Spinal involvement.
- Arthritis mutilans – gross asymmetric joint  

    



Psoriatic arthritis  is different from Rheumatoid Arthritis in that it:


- Affects men and women equally.
- It is an asymmetric arthritis picking out joints randomly
- PIP & DIP joints before MCP jts and wrist
- Dactylitis = sausage like swelling along the length of a  finger or toe

   

                     Here the left ring finger is diffusely swollen and somewhat stiff


- Nail changes – Pitting, Crumbling nails
               - Onycholysis – Lack of adherence of the nail to the nail bed.

     

Diagnosis


- Making the diagnosis is often  Difficult  and often delayed because  there is no single blood test to confirm the diagnosis.


- Often a Family History  ( 40%)


- The Pattern of the Arthritis - see above


- Xrays  - may reveal destructive joint damage with significant bone loss – Osteolysis


             - “Pencil-in-cup” deformity at the DIP joint   


Blood tests – Often normal but may have elevated ESR, CRP,   
                   - Normal Uric Acid & Rheumatoid factor


 MRI Sacroiliac joints


Treatment of Psoriatic Arthritis:
 - There is No cure for psoriatic arthritis,

The objectives of treatment is to:

               - reduce pain and swelling of the joints,

               - prevent joint damage,

               - preserve joint function and

               - control psoriasis of the skin.


Medications    ( See treatment Ladder in inflammatory arthritis )


- Rheumatologist  - Arthritis Specialist review is essential


- Hand therapist  -  splints


- Avoid or reduce stress. Psoriais & Psoriatic arthritis flares can be triggered by stress. Yoga is useful in this regard

 
- Regular exercise to maintain range of motion and muscle strength


- Surgery – Fusion of joints often more reliable than joint replacement in Psoriatic arthritis
                - Make sure  psoriatic skin lesions  are controlled to reduce risk of  infection.