Sacroiliitis is the inflammation of one or both of the sacroiliac joints. These joints are in the lower back, where the spine meets the pelvis. It can lead to pain and stiffness in the lower back, legs, and hips.

Sacroiliitis is associated with many conditions that cause inflammation in the spine. It often occurs secondary to forms of arthritis.

The sacroiliac joints are on either side of the sacrum, the bony structure at the base of the spine. These joints connect the sacrum to the iliac bone, the largest, the uppermost part of the hip bone.

The inflammation of one or both sacroiliac joints may cause pain in the buttocks, lower back, and down a person’s legs.

Due to its often subtle symptoms, a healthcare professional may overlook sacroiliitis when diagnosing patients with lower back pain.

This article looks at the causes, symptoms, and treatments for sacroiliitis.

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There are several potential causes of inflammation in the sacroiliac joints. These include:

  • Ankylosing spondylitis: This is a progressive type of inflammatory arthritis that affects the spine and hips. Sacroiliitis is often an early sign of this condition. Not all people who experience sacroiliitis have ankylosing spondylitis.
  • Trauma: A sudden traumatic injury may damage the sacroiliac joints and cause inflammation, leading to degenerative sacroiliitis.
  • Pregnancy: During pregnancy, the sacroiliac joints stretch to make room for the growing baby. This may put stress on the joints and cause sacroiliitis.
  • Infection: If the sacroiliac joint becomes infected, it becomes inflamed and prone to damage.

Reviews have also associated sacroiliitis with:

Physical actions may aggravate existing sacroiliitis, including sitting or standing for long periods, running, or placing too much weight on one leg for too long.

The main symptoms of sacroiliitis include:

  • pain in the buttocks and lower back
  • pain in the back of one or both legs
  • stiffness in the hips and lower back

Sometimes sacroiliitis can cause pain in the hips and feet, too, although this is less common. Sacroiliitis may also cause pain intermittently. People may experience more pronounced symptoms at night or upon waking.

Sacroiliitis may be hard to diagnose as it can be mistaken for lower back pain caused by different conditions. As a result, a doctor may diagnose sacroiliitis through the exclusion of other conditions.

A doctor may perform several physical tests to assess if sacroiliitis is causing a person’s pain.

These can include applying pressure to the sacroiliac joints and making the patient move their hip joint through various ranges of motion.

A doctor may conduct further screening if unsure of the diagnosis. A 2018 review highlighted the importance of MRI tests as a diagnostic tool for sacroiliitis. However, the authors commented that without significant expertise, the chance of a false-positive diagnosis from MRI imaging is relatively high.

Computed tomography may sometimes be useful in diagnosing sacroiliitis.

There are a variety of treatments available for sacroiliitis. These include medications, exercises, and surgical procedures.


The following medications can help to treat sacroiliitis:

  • Pain relievers: Over-the-counter (OTC) pain medications may provide some relief. A doctor may prescribe stronger medicines if OTC options are not helping.
  • Muscle relaxants: Sacroiliitis can cause muscle spasms that may be painful. Muscle relaxants can help relieve these.
  • TNF inhibitors: This type of medication can help ease sacroiliitis if it is associated with ankylosing spondylitis. A 2016 study showed that TNF inhibitors could significantly improve both activity and joint function.

Home remedies and exercise

As well as prescribed medications, the following home remedies and exercises may help relieve sacroiliitis:

  • Rest: Avoiding the movements that aggravate sacroiliitis can help to reduce inflammation.
  • Ice and heat: Alternating placing ice and heat packs on the affected area may help relieve sacroiliitis.
  • Hip flexion exercises: This exercise involves lying on the back with the legs supported by a box or pillows. A person will then cross one leg over the other, squeeze the legs together, and then release.

In severe cases where medication and exercise do not relieve sacroiliitis, a doctor may recommend one of the following surgeries or procedures:

  • Electrical stimulation: A medical professional may implant an electrical stimulator into the sacrum, which may help to reduce the pain.
  • Joint injections: Injected corticosteroids into the sacroiliac joint can help to reduce inflammation and pain. However, having too many injections in too short a time frame may cause other problems. As a result, doctors will limit the amount a patient can receive.
  • Radiofrequency denervation: This type of treatment works on the nerve tissue that may be causing sacroiliac pain.
  • Joint fusion: In severe cases, fusing the two bones with a metal plate or other fusion devices may help relieve sacroiliitis.

There is a range of treatments available for sacroiliitis that can relieve the pain associated with the condition.

Long-term improvement will depend on the cause of the condition. For example, joint damage and degenerative forms of arthritis will need ongoing treatment to manage symptoms.

A doctor can recommend the best way to manage sacroiliitis symptoms and relieve pain associated with the condition.

Sacroiliitis is a condition that results in one, or both, of the sacroiliac joints becoming inflamed. These joints are between the sacrum, a bony structure at the base of the spine, and the two uppermost hip bones.

Inflammation of the sacroiliac joints can lead to pain in the lower back, buttocks, and legs.

Sacroiliitis often occurs secondary to arthritic conditions such as ankylosing spondylitis. Pregnancy, trauma, and infection may also cause sacroiliitis.

The condition shares symptoms with many mechanical lower back issues. A doctor will use physical tests and often MRI imaging to diagnose sacroiliitis.

A person with sacroiliitis may undertake courses of medication, physical therapy, and in extreme cases surgery, to treat the condition.