Psoriatic Arthritis

People with psoriasis often develop an inflammatory disease of the joints known as psoriatic arthritis. Psoriasis is a long-term autoimmune skin condition associated with red, itchy flakes usually covered with silver scales, mainly on the skin of the scalp, trunk, elbow, and knees. 30% of people with psoriasis also develop psoriatic arthritis associated with red, swollen joints, particularly of fingers and toes.  The involvement of nails may also occur in the form of pitting. In 15% of people, joint disease precedes skin disease. Genetics is thought to play a role in etiology along with obesity and stress as the triggering factors. 

Psoriasis is a multifactorial disease that combines genetics (associated with HLA-B27 ) and susceptibility factors such as type 2 diabetes, obesity, depression, anxiety, cardiovascular diseases, and metabolic syndrome. If one of your parents has it, you are more likely to have this disease inherited from your parents. It is an autoimmune disease in which the body’s defense system gets confused and attacks its own cells. 

Psoriatic arthritis can be classified as;

Oligoarticular: This type is the most common and occurs in around 70% of patients. It is a milder form that involves less than 3 joints and does not necessarily involve the same joints on the other side of the body (asymmetric involvement).

Polyarticular: This type affects 25% of people and is characterized by symmetric involvement of five or more joints of the body. This type resembles rheumatoid arthritis.

Arthritis mutilans: It is severe destructive arthritis that occurs in less than 5% of people. It can progress over months or years resulting in severe joint damage.

Spondyloarthritis: This type affects the joints of the neck or the sacroiliac joint of the spine, causing stiffness and pain. It can also symmetrically involve the hands and feet.

Distal interphalangeal predominant: This type is characterized by marked inflammation of the distal joints of fingers and toes and occurs in 5% of patients. Inflammation on the entire finger or toe is called dactylitis. This is a very painful condition. Nail changes can be severe. 

Around one million people in the USA are affected by psoriatic arthritis. It occurs in 30% of the patients with psoriasis and can affect any age group. It is less prevalent in Asian and African people and has no sex predilection. 

You are prone to developing psoriatic arthritis if you have the following risk factors;

·         Being Overweight

·         Alcohol consumption

·         Tobacco usage

·         Genetic inclination

·         Caucasians

·         Stress 

You may experience the following symptoms if you are suffering from the disease;

• Red, swollen, painful joints.
• In 70% of cases, there is asymmetrical involvement of joints.
• In 15% of cases, joints are affected symmetrically.
• In hands, small joints of fingers are particularly affected, leading to sausage deformity of fingers
• Movement limitation of the joints
• Feeling tired
• Nail changes: Pitting, separation from the nail bed, horizontal ridges
• Skin: Redness, rashes, scales
• Pain in the lower back due to sacroiliitis or spondylitis
• Pain in the feet due to inflammation of the Achilles tendon ( enthesitis)

There are no particular tests to diagnose psoriatic arthritis, but some investigations will help rule out other diseases closely related to psoriatic arthritis, like rheumatoid arthritis, osteoarthritis, etc. A detailed history with particular emphasis on the presence or absence of skin and nail lesions and a thorough physical examination can help to point out the diagnosis of joint pain. The following tests can aid in the diagnosis;

·         Blood tests: ESR and CRP tests may be advised, the increase of which points towards inflammation. Rheumatoid factor (inflammatory proteins) and CCP antibody tests may also be performed, which will be negative in the case of psoriatic arthritis.

·         Imaging tests: X-rays can show disease activity in the joints. It can show decreased joint space due to fusion of the bones or increased joint space due to the destruction of the bony structures. Soft tissue swelling can be seen too. In the advanced stage, the pencil-in-cup deformity can be seen.

·         MRI: It helps to further understand the pathology as detailed bone and cartilage images are produced by a strong magnetic field in MRI. It can show joint space narrowing, soft tissue swelling, erosions, bone proliferation, bone marrow edema, and tendon inflammation.  

·         Synovial Joint Fluid Analysis: Synovial fluid is the fluid in the joint cavity that is aspirated through a needle and sent to the lab to analyze different parameters that can help develop a diagnosis. For psoriatic arthritis, the fluid is inflammatory, with white cell counts in the range of  5000-15,000/µL, and more than 50% of cells are polymorphonuclear leukocytes. 

A lot many disorders can look like psoriatic arthritis, for example;

·         Rheumatoid Arthritis (RA)

·       Gout and Pseudogout

·         Osteoarthritis

·         Lyme Disease

·         Septic arthritis

·         Fibromyalgia

·         Avascular Necrosis

Psoriatic arthritis is managed by prescribing pain medicines that reduce the pain, anti-inflammatory medicines that stop the inflammation, and disease-modifying agents that stop the progression of the disease. Along with these, you would be asked to adopt lifestyle changes to help you tackle the disease, like doing simple exercises and consuming anti-oxidant and Omega-3 fatty-acids-rich food. Certain support groups and occupational therapy are also available.

Pain-relieving drugs: Paracetamol, NSAIDs, and Celecoxib may be prescribed.

Anti-inflammatory drugs: NSAIDs also reduce inflammation but have side effects. Steroids are used in low doses to control inflammation before the commencement of disease-modifying agents.

Disease-modifying agents (DMARDs): These are the group of agents that slow the progression of the disease, improve pain, and prevent damage. They include Methotrexate, Sulfasalazine, Hydroxychloroquine, TNF alpha inhibitors (Infliximab, Etanercept), and Monoclonal antibodies (Rituximab).

Biological response modifiers: This is a new class of medicines that have been manufactured using recombinant DNA technology from living cells cultured in a laboratory. They target specific parts of the immune system and are given by IV infusion in the vein or by injection. Examples include; TNF-α Inhibitors, including Etanercept, Infliximab, Golimumab, IL-12/IL-23 Inhibitor Ustekinumab, IL-17a Inhibitor Secukinumab, and Jak inhibitor, Tofacitinib.

Phosphodiesterase-4 inhibitors: They are approved recently and function by decreasing the production of various inflammatory chemicals by inhibiting the phosphodiesterase-4 enzyme. Examples include Apremilast given in tablet form.

Surgery

Depending upon your symptoms and joint destruction, your doctor may suggest some surgical therapies especially if the joint is deformed and medical therapies are insufficient.

These surgeries include the following;

• Synovectomy: The inflamed synovial lining around your joint is removed to reduce pain and improve joint movement.
• Tenosynovectomy: The inflammation damages your tendons and synovium, which are removed in this surgery.
• Reconstructive Surgery /Arthroplasty: The whole joint can be reconstructed to improve function.
• Arthrodesis: In this procedure, your joints may be fused to align them or relieve pain.

Psoriatic arthritis is a long-term disease. It has no cure. There are periods of relapse and remissions in this disease. Although it is not a life-threatening disease, it's quite debilitating. It was initially considered a mild form. However, 40% of people now develop progressive destructive disease. 

Several studies have revealed some of the precipitating factors of psoriasis and psoriatic arthritis which should be avoided to cope with the illness like;

• Avoid alcohol and dairy.
• Managing stress as it is beneficial to reduce flare-ups.
• Some medications trigger the disease, such as high blood pressure drugs, antimalarial medication, and lithium, so these medications should be avoided.
• It is advisable to lose weight.
• Avoid red meat, refined sugar, dairy products, and junk or processed food as they have been known to cause flare-ups.
• Exercise can lower chronic inflammation as well. Therefore, it is beneficial to adopt exercise if the patient is suffering from the disease and for overall general wellbeing. Gentle exercises can have a good impact on your joint mobility.
• Taking rest and applying cold/hot patches on inflamed joints.
• Splints and braces can be used to support the disabled joint.
• Diet modification: The patients are advised to take a high amount of fish oil with EPA and DHA acids.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 27, 2023.

References

Psoriatic Arthritis (rheumatology.org)

https://rheumatology.org/patients/psoriatic-arthritis

Psoriatic arthritis - PMC (nih.gov)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6758836/