Psoriatic arthritis is one of over 100 different types of arthritic conditions that is often associated with individuals who suffer from psoriasis of the skin. Psoriasis is a chronic condition that affects 2% of the Caucasian population in the United States. Individuals who suffer from psoriasis experience patchy, raised, red areas of the skin that become flamed and scaling. The most common areas of the body that are affected are the elbows, knees, scalp, naval and around the genital areas. About 10% of those who suffer from psoriasis will also develop and associated inflammation of the joints, called psoriatic arthritis. (1)
For the most part, individuals who suffer from psoriasis start to see symptoms prior to the age of 20. The onset of psoriatic arthritis generally happens in individuals in their 40s and 50s. Men and women are affected equally and the skin disease will precede the arthritis in nearly 80% of the patients. If the arthritis begins before the psoriasis the diagnosis can be difficult and the disease may be more severe.
Psoriatic arthritis is a systemic rheumatic disease, which means that it causes inflammation in body tissues other than in the joints. For instance, the eyes, heart, lungs and kidneys can be affected. Research has shown that persistent inflammation in the joints from psoriatic arthritis can lead to damage that is permanent. Early diagnosis is important to avoid this joint damage. (2)
At this time the exact causes of psoriatic arthritis are not known. While researchers know that individuals who have psoriasis are more at risk, not all individuals with psoriasis will develop psoriatic arthritis. At this point researchers are unsure if there is a genetic role in the disease but do know that 40% of those who develop psoriatic arthritis will have a family member who has psoriasis or arthritis. Another theory is that psoriatic arthritis can result from an infection that activates the immune system.
Individuals who suffer from psoriatic arthritis will experience pain in their affected joints, swelling in their joints and joints that become warm to the touch. Physicians have identified five different types of psoriatic arthritis which will affect the symptoms that individuals experience over time. The mildest form is called asymmetric psoriatic arthritis that affects joints on only one side of the body, or different joints on each side of the body. Most often fewer than five joints are involved.
When pain occurs on both sides of the body and is symmetrical it is called symmetric psoriatic arthritis. More than five joints are often affected and it appears that more women than men are at risk for symmetric psoriatic arthritis. The psoriasis that is associated with this condition tends to be more severe. Another form of psoriatic arthritis is distal interphalangeal joints, which is rare in occurs mostly in men. In this type the smallest joints closest to the nails of the fingers and toes are affected.
Another form is called spondylitis which causes inflammation of the spine as well as a stiffness and pain in the neck, lower back or sacroiliac joints. In approximately 50% of those who present with spondylitis a genetic marker can also be found. The fifth type is destructive arthritis which a small percentage will experience. This is a severe, painful and disabling form of psoriatic arthritis which destroys the small bones of the hands and leads to permanent deformity and disability. (3)
Aside from the arthritis and changes in the spine, psoriatic arthritis can also inflame other organs in the body. Inflammation of the coloured part of the eye can cause iritis. Corticosteroids are sometimes necessary to prevent blindness. Inflammation around the lungs causes chest pain. Inflammation of the aorta can cause leakage of the valves leading to heart failure and shortness of breath.
Doctors have noted that 80% of patients who suffer from psoriatic arthritis will also have pitting and ridges seen in the fingernails and toenails. These particular nail changes are observed in only a minority of patients who also experienced psoriasis but do not have arthritis. There is also an increasing frequency of individuals who have psoriatic arthritis and also suffer from acne.
Your physician or rheumatologists will assess the signs and symptoms you present with and try to rule out other causes of joint pain, such as osteoarthritis. The physician will often recommend x-rays, tests of the joint fluid, blood tests for sedimentation rate and rheumatoid factor and will perform a thorough physical examination. (4)
Because no causative agent has been discovered there is also no cure for psoriatic arthritis. The physician may prescribe nonsteroidal anti-inflammatory drugs or salicylates to reduce the pain and inflammation of the joints. Individuals who have severe arthritis may also be prescribed disease modifying antirheumatic drugs such as methotrexate.
Currently, there are newer medications on the market that block the inflammatory protein called tumour necrosis factor and are fast becoming the treatment of choice. Three of these medications include Humira, Enbrel and Remicade. On occasion physicians may inject joints which are particularly painful with steroid medications to help reduce the inflammation. In other cases, joint replacement surgery may be required in order to allow the individual to continue to be functional. In almost all cases the physician will suggest a mix of rest and exercise in order to help support the joints. Physical therapy will help increase the movement of specific joints and teach individuals the types of exercises which will improve muscle strength, support the joints and reduce the damage.
Future treatment protocols continue to evolve as researchers test different drug therapies and vitamins in the prevention and treatment of psoriatic arthritis. In a recent study it was shown that vitamin D can improve arthritis in individuals who suffer from psoriatic arthritis. Thankfully, the course of this disease is often mild and affects only a few joints. In only rare cases do individuals suffer from severe psoriatic arthritis.
This particular type of arthritis also tends to alternate between flare ups in periods of improvement. Factors that will influence how severe the diseases includes clinical pattern, age at which the symptoms appeared, severity of any skin symptoms and family history of arthritis.
As with any other disease psoriatic arthritis responds best when found early. Therefore early diagnosis and treatment is essential to decreasing the damage done to the joints and improving the overall function in reducing the disability of individuals who suffer from this disease.
Updated 15th September 2017
(1) American Academy of Dermatology: Psoriatic Arthritis
(2) American College of Rheumatology: Psoriatic Arthritis
(3) National Psoriasis Foundation: Types of Psoriatic Arthritis
(4) Johns Hopkins Arthritis Center: Psoriatic Arthritis
MayoClinic.com: Psoriatic Arthritis
National Psoriasis Foundation: Diagnosing Psoriatic Arthritis