Sacroiliitisis inflammation of the sacroiliac (SI) joint in the pelvic region of your body.
This can lead to symptoms of pain in the lower back and buttocks.
Sacroiliitis can be brought on by several different medical conditions, including some types of inflammatory back pain.

Illustration by JR Bee, Verywell
In addition to pain, some people also describe numbness, popping, or clicking below their waistline.
Climbing stairs, walking with large strides, and running are other weight-bearing activities that make the pain worse.
These related conditions appear to result from a combination of genetic and environmental causes.
Ankylosing spondylitis is a punch in of spondyloarthropathy.
Your doctor may evaluate your medical history and lifestyle when you come in for a diagnosis.
Understanding your genetic predisposition for this condition can be helpful in finding the proper diagnosis and treatment.
Sacroiliac joint problems are highly recurrent within families.
A combination of imaging and lab tests can help with diagnosis.
Of these, the use of fluoroscopy is the most common.
Before the procedure, you will be asked not to take any pain medicine.
However, a local anesthetic is generally used to make you more comfortable during the procedure.
From there, the provider can further investigate the cause and suggest treatment.
Laboratory Tests
Other laboratory tests are also sometimes helpful in assessing the underlying causes of sacroiliitis.
Treatment
Treatment of sacroiliitis will vary based on the underlying cause.
Two are FDA-approved for this condition:
Physical therapy andregular exercisecan also often be very helpful.
If sacroiliitis is left untreated, it is unlikely to resolve on its own.
Depending on the cause of your condition, it may develop into something more serious.
Symptoms include pain, often felt on only one side of the body.
Talk to your provider about lifestyle modifications and medications to manage pain.
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