On their own psoriasis and arthritis are conditions that can be very difficult for patients to cope with, but sometimes, people diagnosed with psoriasis may also develop swelling, stiffness, and pain in and around the joints. This is known as psoriatic arthritis or PsA. PsA affects both the skin and the joints. It is characterized by a scaly, reddish rash and inflammation on the hands, feet, elbows, knees, and ankles. This is a chronic inflammatory disease that unfortunately cannot be cured.

Types of psoriatic arthritis
Not all psoriatic arthritis patients are diagnosed with the same type of the condition. There are 5 major types of psoriatic arthritis. The type of PsA plays an important role in determining the best course of treatment.

Symmetric psoriatic arthritis
As the name suggests, this type of psoriatic arthritis affects both sides of the body. In such cases, the same joints on both sides of the body appear inflamed with red, scaly rashes. Moving these joints may be very painful. As the disease progresses, it can cause a loss of function. It is important to note that some patients may have a mild loss of function while others may have a much more severe loss of function. The disease is often compared to rheumatoid arthritis.

Asymmetric psoriatic arthritis
Unlike the first type of psoriatic arthritis, this affects joints on only one side of the body. It may affect one to three joints in the body. These may be large such as the hip and knee or small such as the fingers and toes. It is not necessary for all the joints affected to be on the same side of the body. For example, it may affect the finger joints on the right hand and the left knee.

Distal interphalangeal predominant (DIP)
This type of psoriatic arthritis is restricted to small joints of the fingers and toes. The joints closest to the nails are at the highest risk of developing inflammation and rashes associated with the condition. In many cases, DIP psoriatic arthritis may be confused with osteoarthritis- a more common form of arthritis that causes progressive deterioration of cartilage in the joints.

Spondylitis
Spondylitis is also a type of psoriatic arthritis. This type of PsA affects the spinal column. Inflammation between the bones of the spine causes stiffness and makes movement painful. Spondylitis commonly affects the bones of the neck, spinal vertebrae, lower back and pelvic area or sacroiliac region. It may also affect connective tissue such as the ligaments or trigger arthritic flare-ups in the arms, legs, hips, and feet.

Arthritis mutilans
This is the most severe form of psoriatic arthritis. Like DIP PsA, this destructive form of PsA affects the small joints of the fingers and toes that are closest to the nail. It can be so destructive and deforming that the patient may lose complete functioning of the affected joints. Arthritis mutilans is also often associated with pain in the neck and lower back. This type of psoriatic arthritis is very rare.