People with psoriatic arthritis may have symptoms of both psoriasis and arthritis. The condition causes widespread inflammation and can affect the skin, musculoskeletal system, immune system, vision, and more.

Psoriatic arthritis (PsA) affects up to 30% of people who have the skin condition psoriasis.

Here, we describe eight effects of PsA, including the effects on vision, digestion, breathing, and movement. We also explore the treatment options.

psoriatic arthritis effects on the body
Image credit: Stephen Kelly, 2019

Many people with PsA also have psoriasis. Some possible symptoms of plaque psoriasis, the most common type, include:

  • rough, scaly patches of skin
  • a raised, silvery coating on some of these patches
  • changes in skin color
  • flakes on the scalp that may resemble dandruff
  • thickened nails
  • ridged, pitted, or crumbling nails
  • nails separating from the nail bed, known as onycholysis
  • itching and pain

Skin symptoms usually affect the elbows, knees, lower back, and scalp, but they can occur anywhere. Nail symptoms occur in 80–90% of people with PsA, whether or not they have psoriasis.

Psoriasis speeds up the life cycle of skin cells. New cells move to the outer layer of skin in a few days rather than weeks. These new cells rapidly build up on the skin to form the itchy, scaly patches that characterize psoriasis.

Around 68% of people who develop PsA already have skin symptoms of psoriasis, and about 15% of people with PsA develop symptoms of psoriasis at the same time.

Skin symptoms only appear after symptoms affecting the joints and other areas in about 17% of cases.

How does psoriasis look on black skin?

The immune reaction involved in psoriasis and PsA causes inflammation of the joints, affecting the musculoskeletal system in several ways. Inflammation causes pain, stiffness, and swelling in one or more joints, making them difficult to move.

PsA symptoms usually affect up to five small or large joints on one side of the body. The symptoms of rheumatoid arthritis, by contrast, often develop on both sides. For example, the condition may develop in both knees.

According to the American Academy of Dermatology, early symptoms of PsA may include:

  • swelling and tenderness in a joint, particularly a finger or toe
  • heel pain
  • swelling just above the heel
  • stiffness when a person wakes up that improves during the day

Swelling often occurs throughout the fingers. The affected fingers and toes may develop a sausage-like appearance known as dactylitis, and this may be most prominent in the middle joints of the fingers. The finger bone may also change shape, which doctors can recognize using imaging technology. The middle bone in a finger joint becomes narrower, and the end joint becomes wider.

PsA may also cause inflammation in the back and pelvis, known as spondyloarthritis.

How does it affect cartilage?

In arthritis, the cartilage at the end of the bones becomes damaged and breaks down. In PsA, this damage results from persistent inflammation. As the cartilage erodes, the bones rub together, causing further pain and joint damage. Inflammation can also lead to bone erosion and extra bone growth.

Chronic inflammation can also affect the ligaments and tendons around the joint.

PsA is an autoimmune condition, which means that it influences the way that the immune system works. The immune system fights pathogens, such as bacteria and viruses. In someone with an autoimmune condition, it mistakenly attacks healthy cells.

In a person with PsA, the immune system attacks the joints, tendons, and the insertion points of tendons and ligaments. If a person also has psoriasis, it also affects the skin.

Researchers do not fully understand why this happens. They think that some bacterial infections, including strep throat, may trigger PsA. In addition, if a person has a genetic susceptibility, they may develop PsA as a result of severe stress, a physical injury, or an event that causes the immune system to react strongly.

Learn more about the relationship between psoriasis and the immune system.

Inflammation in and around the eyes can affect vision. Some 7–20% of people with psoriasis develop uveitis, and it is more common in people who have PsA than in those who have psoriasis alone.

Uveitis is a group of diseases related to eye inflammation. Without treatment, it can lead to vision loss. People with PsA should have regular eye exams for this reason.

There is a link between inflammatory bowel disease (IBD), such as Crohn’s disease, and PsA because inflammation underlies both conditions. IBD causes diarrhea and other gastrointestinal symptoms.

People with PsA have a significantly increased risk of developing IBD, according to research from 2017. Other studies suggest that psoriasis is eight times more common in people with Crohn’s disease.

Learn more about PsA’s link to the digestive system.

People with PsA appear to have a higher chance of developing chronic obstructive pulmonary disease (COPD), according to a 2015 review.

A 2019 study concluded that there may be a link between COPD and various types of inflammatory arthritis, but that more research is needed to find out why this happens.

How can psoriasis affect the lungs?

People with PsA have a higher risk of cardiovascular disease than those without it. The American College of Cardiology explains that chronic inflammation damages blood vessels by making them thicker and harder and by causing scarring, known as atherosclerosis. This can increase the risk of angina, a heart attack, or stroke.

Among people with PsA, there are also higher rates of metabolic syndrome. This includes conditions such as obesity, high blood pressure, diabetes, and high cholesterol. These, too, can put added stress on the blood vessels and the cardiovascular system.

PsA can affect mental and emotional, as well as physical, health. Symptoms such as pain and fatigue and other related health concerns can increase the risk of anxiety and depression in people with PsA.

Psoriasis and PsA may also reduce self-esteem and cause feelings of embarrassment, especially when treatments do not adequately manage symptoms.

Treatments for PsA aim to:

  • manage symptoms
  • reduce the frequency and severity of symptoms
  • slow the progression of the disease
  • prevent permanent damage

Some guidelines recommend biologic medication, such as etanercept (Enbrel), for people with a new diagnosis of PsA. Biologic drugs are not suitable for everyone, however, and they can have adverse effects. A person with PsA should discuss the range of treatment options with their doctor.

A doctor may recommend:

  • nonsteroidal anti-inflammatory drugs, such as ibuprofen (Advil), and other medications to manage pain and inflammation
  • steroid injections to ease inflammation
  • joint replacement surgery, when damage to a joint is severe

The following may also help:

  • physical and occupational therapy
  • maintaining a moderate weight
  • low-impact forms of exercise, such as yoga or tai chi
  • massage therapy
  • acupuncture
  • avoiding or quitting smoking
  • seeking support from others, such as family, friends, or a therapist

Can changing the diet help?

PsA involves inflammation in the joints, leading to swelling, pain, and stiffness. It can also cause fatigue, nail changes, and other symptoms, and people with the condition have a higher risk of cardiovascular disease and depression. Many people with PsA also have skin symptoms characteristic of psoriasis.

There is no cure for PsA, but medication can help manage it and prevent progressive joint damage. Alternative therapies and lifestyle strategies such as maintaining a moderate weight may also help.