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Psoriatic Arthritis: Inflamed Skin and Joints
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According to the Centers for Disease Control and Prevention in the US, more than one-third of adults who have arthritis complain that their condition interferes with work and leisure activities. Up to 25% of them also reveal that it is a big source of pain, giving it a score of seven or higher on a 10-point scale.

Inflammatory arthritis refers to the inflammation of one or more of your joints. The most obvious symptoms are pain, swelling and morning stiffness in the affected joints.

Arthritis exists in myriad forms - there are more than 100 types of arthritis and related diseases. The most common ones include rheumatoid arthritis, osteoarthritis, gout, fibromyalgia and psoriatic arthritis. All of them cause pain in different ways. This article focuses on the condition known as psoriatic arthritis (PsA).

What is PsA?

When you see the word ‘psoriatic’, you probably suspect that the condition has something to do with psoriasis, a non-infectious condition that leaves the skin itchy and scaly, occurring most commonly on the scalp, knees and elbows. It could also make the nails crumbly.

Psoriasis is an autoimmune disease, meaning the patient’s immune system is turning on his own body, thus causing inflammation and pain.

A portion of psoriasis patients goes on to develop psoriatic arthritis, when the body’s immune system starts attacking the joints. Most of these patients develop the skin condition first before their joints start to hurt.

Research shows that about a third of people who have psoriasis will go on to get psoriatic arthritis, usually when they are between 30 and 55 years of age.

PsA is an equal-opportunity condition, and is just as likely to strike a man as a woman, unlike many other autoimmune diseases, which affects women more frequently.

5 Types of PsA

1  
Symmetric

Many PsA cases fall under this particular type. The term refers to the fact that joints on both sides of the body are affected at the same time. This type of PsA is similar to rheumatoid arthritis.
 
2  
Asymmetric

This term is used when different joints are affected on each side of the body. This often milder form of PsA occurs in about 35% of PsA sufferers.
 
3  
Distal

This type causes inflammation and stiffness near the ends of the fingers and toes. Toenails and fingernails could also be affected by pitting, white spots and lifting from the nail bed.
 
4  
Spondylitis

In this type of PsA, pain and stiffness in the spine and neck are common signs.
 
5  
Arthritis mutilans

This is the most severe of the five and affects about 5% of PsA patients. It deforms the small joints at the ends of fingers and toes, and can destroy them.
 

Symptoms of PsA

  • Joint pain, often coupled with swelling
    Psoriatic arthritis usually affects the toes, ankles, knees, fingers and lower back.
  • Dactylitis
    A sausage-like swelling — dactylitis — along the entire length of a finger or toe can form. This is the easiest way to distinguish PsA from rheumatoid arthritis, which is another form of arthritis caused by a faulty immune system. In rheumatoid arthritis, swelling and inflammation occurs only at affected joints.
  • Enthesitis
    People with psoriatic arthritis often experience pain at the tendon and ligaments, most commonly in the elbow or at the heels. This is another distinguishing sign and symptom of psoriatic arthritis.

Causes of PsA

While scientists are still not sure what causes PsA, many believe genetic predisposition plays a large part. Studies show that family links are strong for this disease compared to other autoimmune rheumatic diseases. According to the Arthritis Foundation, 40% of people with PsA have family members affected by the same disease.

Diagnosing PsA

This can get rather tricky as PsA resembles many other forms of arthritis such as gout, rheumatoid arthritis and osteoarthritis.

A rheumatologist, who specialises in arthritis and musculoskeletal diseases, should be consulted. He will usually base his diagnosis after doing the following:
  • Medical history
    He will take the patient’s medical history, such as noting down the pain description and location.
  • Physical examination
    He will take a close look at the inflammation and swelling of the joints and observe the signs of psoriasis.
  • Diagnostic tests
    He may order scans and tests, such as an X-ray (to check for changes in the bone) and blood tests (to check for the presence of a rheumatoid factor and other antibodies - usually negative in people with PsA; should it be positive, rheumatoid arthritis should be suspected instead).

Treatment options

Some medications available for treating PsA treat the symptoms only: for skin problems, topical medication is applied directly to the scaly spots; for joint problems, nonsteroidal anti-inflammatory drugs (NSAID) can be used. It is more important to start the patient on disease-modifying anti-rheumatic drugs (DMARD), which modifies the immune system to control the illness.

 
 
 
A/PROF LEONG KENG HONG

MBBS (Singapore) 1983
Master of Medicine (Singapore) 1989
Doctor of Medicine 2005
Member of the Royal College of Physicians (UK) 1989
Fellow of the Academy of Medicine, (Singapore) 1992
Fellow of the Royal College of Physicians (Edinburgh) 1997

Leong Keng Hong Arthritis and Medical Clinic
6 Napier Road #04-18
Gleneagles Medical Centre

Singapore 258499
Tel : (65) 6472 4337
Fax : (65) 6472 0691
Email : info@leongkenghong.com
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