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Hot Spots

“Hot spots” are areas of the body that are painful to the touch. Hot spots, also called enthesitis, can occur in people with ankylosing spondylitis (AS). Entheses are the locations where tendons and ligaments attach to the bones, and “-itis” means inflammation. Enthesitis causes soreness and swelling.1

Where tendons and ligaments attach to the bones

A person stands with one hand on chest and the other over belly

The progression of AS

AS progresses at different speeds in different individuals, and there is no single pattern that is common to all people with AS. Researchers believe that enthesitis is the first area of inflammation that occurs with AS.2 As these hot spots are subjected to chronic inflammation, the bone begins to wear away. The body then rebuilds the bone tissue, but too much bone can be formed, causing a fusion of the joint or calcification of the spinal ligaments, called syndesmophytes.3

Other causes of enthesitis

In addition to AS, enthesitis can be caused by injury or overuse of an area, such as what occurs in sports.1 Enthesitis may also be a symptom of other conditions like psoriatic arthritis, or chronic inflammatory conditions like rheumatoid arthritis.1,2

Common sites of enthesitis in people with AS

Common locations of enthesitis in people with spondyloarthritis like AS include2:

  • Achilles tendon (back of the heel)
  • The arch of the heel
  • In the knee
  • In the bones of the feet
  • In the spine

How is enthesitis evaluated?

Enthesitis can be evaluated during a physical examination or through the use of imaging technology, such as a magnetic resonance imaging (MRI) scan.4 One evaluation tool that was developed to assess enthesitis in people with AS is called the Maastricht Ankylosing Spondylitis Enthesitis Score (MASES). The MASES tool outlines 13 points on the body that should be evaluated by touch by a healthcare professional. These points are located around the pelvis bones, the spine, and the heels. Other tools that have been developed include the Leeds Entheses Index (LEI), the University of California, San Francisco (UCSF) index, and the Berlin index. Each of these tools uses a different number and pattern of points, and there is no clear recommendation on which is best. These tools may be used during diagnosis and to evaluate how well a particular treatment is working.5

How is enthesitis treated?

Enthesitis is treated along with the other symptoms of AS with a combination of medication, exercise, and physical therapy. Medications for AS include6,7:

All people with AS should engage in exercises as part of their treatment regimen. While physical therapy isn’t believed to prevent the progression of the disease, it can minimize the symptoms in certain patients.

Written by: Emily Downward | Last reviewed: February 2019
  1. Enthesitis symptoms and treatments. Enthesitis.org. Available at http://enthesitis.org/. Accessed 1/21/19.
  2. Kataria RK, Brent LH. Spondyloarthropathies. Am Fam Physician. 2004 Jun 15;69(12):2853-2860.
  3. D. J. Pradeep, A. Keat, K. Gaffney; Predicting outcome in ankylosing spondylitis, Rheumatology, Volume 47, Issue 7, 1 July 2008, Pages 942-945, https://doi.org/10.1093/rheumatology/ken195
  4. Benjamin M, Toumi H, Ralphs JR, et al. Where tendons and ligaments meet bone: attachment sites ('entheses') in relation to exercise and/or mechanical load. J Anat. 2006 Apr;208(4):471-490. doi: 10.1111/j.1469-7580.2006.00540.x
  5. Mease PJ, Van den Bosch F, Sieper J, et al. Performance of 3 enthesitis indices in patients with peripheral spondyloarthritis during treatment with adalimumab. J of Rheum. 2017;44:5. doi: 10.3899/jrheum.160387.
  6. Medications used to treat ankylosing spondylitis and related diseases. Spondylitis Association of America. Available at https://www.spondylitis.org/Medications. Accessed 1/21/19.
  7. Pappas S. New treatment guidelines for ankylosing spondylitis. Rheumatology Network. Available at http://www.rheumatologynetwork.com/psoriatic-arthritis/new-treatment-guidelines-ankylosing-spondylitis. Accessed 1/21/19.