Psoriatic arthritis (PsA) and sacroiliitis are both inflammatory conditions that affect the joints. It is possible for people to have one or both of these conditions.

PsA is a chronic autoimmune condition that can cause painful inflammation in any joint, including the ankles, feet, hands, and knees. In contrast, sacroiliitis causes painful inflammation of the sacroiliac joints in the lower back.

The two conditions have different causes, symptoms, and treatment options. However, PsA is one of several conditions that can lead to sacroiliitis.

This article examines the link between PsA and sacroiliitis, including the symptoms, diagnosis, and treatment of both conditions and when to speak with a doctor.

A person with psoriatic arthritis and sacroiliitis holding their lower back. -2Share on Pinterest
Oleg Elkov/Getty Images

PsA causes joints to become stiff, painful, and swollen. This condition occurs due to the immune system mistakenly attacking healthy joint tissue.

Although PsA typically affects joints in the knees, ankles, feet, and hands, it can affect other joints. When PsA affects the sacroiliac joints, it can cause sacroiliitis. The sacroiliac joints are in the lower back, where the pelvis joins the spine.

According to a 2020 study, inflammation in the sacroiliac joints can be an early indication of PsA. The study’s authors suggest that, from a small sample size of 45 people with PsA, 37.8% had signs of sacroiliitis.

However, the two conditions do not always co-occur, and a person may have one or both.

Other causes of sacroiliitis

Other potential causes of sacroiliitis include:

The symptoms of PsA and sacroiliitis may differ. However, if PsA affects the sacroiliac joints, it may cause sacroiliitis. If the conditions occur together, a person may have symptoms of both conditions, especially in the lower back.

PsA symptoms

Symptoms of PsA include:

Sacroiliitis symptoms

Sacroiliitis can cause pain in the lower back, hips, buttocks, and groin. Pain may be dull, sharp, aching, or stabbing. It may also extend down the legs. The pain may become more pronounced after:

  • standing for a prolonged period
  • running
  • climbing stairs
  • putting more weight on one leg
  • getting up from a chair

A doctor may use similar methods to diagnose PsA and sacroiliitis, including the following:

If a doctor suspects someone has PsA, they may refer the person to a rheumatologist, a doctor specializing in arthritis.

If a doctor suspects someone has sacroiliitis, they may apply pressure to the affected joints, ask the person to flex their hips, or administer a numbing injection (anesthetic) to the sacroiliac joints to see if pain originates there.

Treatment plans for each condition may vary, particularly depending on the extent of the condition. Doctors may tailor a treatment plan to a person’s symptoms and specific needs.

PsA treatment

Treatment for PsA aims to manage symptoms and slow the progression of the condition. A treatment plan will depend on the severity of the condition, the amount of joint damage, patient preference, and the presence of comorbidities.

Treatment for PsA may include:

Doctors may also recommend lifestyle changes, such as quitting smoking, weight loss, and gentle, regular exercise, depending on which actionable steps best complement a person’s treatment plan.

Sacroiliitis treatment

Treatment for sacroiliitis may include:

If a person is experiencing persistent pain, swelling, and stiffness in the joints, it is recommended that they contact a doctor as soon as possible. These symptoms could indicate several conditions.

A doctor can give an accurate diagnosis to determine whether someone has PsA or sacroiliitis.

Treatment may help relieve symptoms as well as slow the progression of PsA and some of the causes of sacroiliitis.

PsA is a chronic autoimmune disease that sometimes co-occurs with psoriasis. In people with PsA, the immune system mistakenly attacks healthy joint tissue, causing pain, swelling, and stiffness.

PsA is one potential cause of sacroiliitis, inflammation in the sacroiliac joints in the lower back where the pelvis and spine meet. Signs of sacroiliitis may be an early indicator of PsA.

Some methods of diagnosis and treatment are similar for both conditions, including blood tests, imaging tests, and certain medications, including NSAIDs and corticosteroids.

If a person thinks they may be experiencing symptoms of PsA or sacroiliitis, it is important that they speak with a doctor.