Symptoms of Psoriatic Arthritis

Psoriatic arthritis (PsA) symptoms such as pain and joint stiffness may seem distinct from those related to psoriasis, but they are actually a direct consequence of the disease. The inflammation that results when the immune system suddenly attacks normal cells in the outer layer of skin can "spill over" and eventually impact other cells and tissues. Over time, the same inflammation that gave way to skin changes can lead to the development of psoriatic arthritis. It is even possible to have psoriatic arthritis with no skin involvement at all.

It is important to recognize the signs and symptoms of psoriatic arthritis so that a doctor can diagnose the disease and start treatment as soon as possible.

Psoriatic arthritis symptoms vary from person to person. They tend to develop in episodes, known as flares, in which symptoms suddenly appear and just as suddenly resolve.

Unlike psoriasis, in which the immune system directly attack skin cells, psoriatic arthritis is caused almost entirely by inflammation. Common symptoms include:

• Pain and swelling in one or more joints, typically the wrists, knees, ankles, fingers, toes, and lower back
• Swelling of the fingers and toes, known as dactylitis, resulting in a thick, sausage-like appearance
• Morning stiffness, similar to osteoarthritis
• Silvery-white skin lesions (plaques) often on the scalp, elbows, knees, and lower spine

• Pitting or lifting of the nails, also referred to as nail dystrophy
• Persistent fatigue, common with chronic inflammatory diseases
• Eye problems, including uveitis and conjunctivitis (pink eye)

There are five subtypes of psoriatic arthritis, each of which is characterized by its location and severity. It is not uncommon for a person to switch from one subtype to another. Scientists are unsure why this is but believe that certain environmental triggers can alter the already-abnormal immune response.

The changes in subtype also reflect the progressive nature of the disease. As certain joints sustain damage, often irreversible, the inflammatory response may simply broaden and affect other joints in the body.

Moreover, it is possible to have multiple subtypes or to develop other forms of arthritis, both autoimmune and non-autoimmune.

Asymmetric Psoriatic Arthritis

Psoriatic arthritis is asymmetric when a joint is affected on only one side of the body. Asymmetric psoriatic arthritis tends to be milder than other forms of the disease and is often the first type experienced. According to a 2013 review in the Polish Journal of Radiology, asymmetric psoriatic arthritis accounts for roughly 70% of all cases.

Symmetric Psoriatic Arthritis

Symmetric psoriatic arthritis, as per its name, is characterized by pain and swelling in the same joints on both sides of the body. Fingers and toes are typically affected, as well as larger joints of the hips and knees.

Symmetrical psoriatic arthritis accounts for around 15% of all cases. It is often preceded by asymmetric disease but may develop symmetrically from the start.

The symmetrical pattern is similar to that of rheumatoid arthritis, an autoimmune disease that directly targets joint tissue. Because of this, it can be difficult to differentiate the diseases without the use of a rheumatoid factor (RF) blood test.

Distal Interphalangeal Predominant (DIP) Psoriatic Arthritis

Distal interphalangeal predominant (DIP) psoriatic arthritis may sound complicated, but it simply means that the distal (near the nail) joints of the phalanges (fingers or toes) are affected.

This type of psoriatic arthritis is characterized by pain and stiffness near the tips of the fingers or toes. When viewed on an X-ray, the ends of the bone will often appear narrowed like a pencil tip, while the adjacent joint will have a compressed, cup-like appearance.

Nail changes, including pitting, thickening, and lifting (onycholysis), are also common.

Arthritis Mutilans

Arthritis mutilans is an uncommon but severe form of psoriatic arthritis. It is characterized by a condition called enthesitis in which the tissues connecting tendons and ligaments to bone become inflamed. Arthritis mutilans is believed to affect around 5% of people with psoriatic arthritis.

The aggressive nature of the disease can cause bone resorption (the breakdown of bone tissue), cartilage loss, and joint deformity.

Severe cases may require surgery to either relieve joint compression (arthroscopic debridement) or fuse the joints to reduce pain (arthrodesis).

Psoriatic Spondylitis

Spondylitis refers to inflammation of the spinal column. Only around 5% of people with psoriatic arthritis will have spondylitis as their main symptom. Although the spine is less commonly affected by psoriatic arthritis than other joints, it is not uncommon to have stiffness in the neck, lower back, and pelvis (particularly the sacroiliac joint).

Another common denominator is the genetic marker human leukocyte antigen B27 (HLA-B27), which is present in over half of the people with psoriatic spondylitis.

As a general rule, you should suspect psoriatic arthritis if you have symptoms of psoriasis or a family history of autoimmune diseases. At the same time, it is not uncommon to have multiple autoimmune disorders given that the diseases often share the same genetic mutations.

Early diagnosis and treatment are key to bringing the disease under control. Doing so can help slow disease progression, prevent joint damage, and improve your overall quality of life.

If you develop symptoms of psoriatic arthritis, ask your doctor for a referral to a joint specialist known as a rheumatologist.

While many internists are capable of managing mild psoriasis, psoriatic arthritis is a far more complicated disease. It is not only more difficult to diagnose but often requires a combination of drugs, including disease-modifying antirheumatic drugs (DMARDs) like methotrexate and newer-generation biologic drugs like Enbrel (etanercept) and Humira (adalimumab).