Ankylosing spondylitis (AS) is a type of inflammatory arthritis that mainly affects your spine. But in about a third of cases, it also causes problems in other body parts, including your feet.
AS can lead to stiffness and/or pain in your ankles, heels, toes, or the soles of your feet. The pain can be mild, or serious enough to interfere with walking and your quality of life.
What Foot Problems Can Ankylosing Spondylitis Cause?
AS may affect your feet in several ways. Most foot problems result from inflammation in your joints or your entheses, places where tendons and ligaments are attached to your bones. This inflammation leads to conditions such as:
Plantar fasciitis. The plantar fascia is a band of tissues that joins your heel bone to the base of your foot. It supports the arch of your foot, absorbs shock from the ground as you walk, and helps propel your steps. Inflammation there is called plantar fasciitis, and it causes serious foot and heel pain when you stand or put weight on your foot. The pain may range from mild to sharp, and affect one or both of your feet.
Sometimes it’s worse when you take your first steps in the morning or after you’ve been still for a while. Some people call this pain “first-step pain.” It could go away in 5 or 10 minutes.
Your pain may also be worse after you stand or sit for a long time. You might get some relief when you first start to walk around, but the pain could worsen the longer you stay active.
Achilles tendonitis. AS can also affect your Achilles tendon, the band of tissues that joins your calf muscles to your heel bone. Your Achilles tendon lifts your heel, helping you walk, jump, climb, and stand on your toes.
Inflammation in your Achilles tendon (Achilles tendonitis) causes pain or stiffness in the back of your heel and your lower calf. You might see swelling or lumps in the area.
You could have tenderness or stiffness in the morning that gets better as you move around. It may get worse again when you stay either still or active for long periods.
You might have serious pain when you do short bursts of vigorous or high-impact activity, like running or jumping.
Toe dactylitis. When inflammation from AS affects your toes, they swell and turn red. This condition is called toe dactylitis. Since your swollen toes may resemble sausages, this condition is also called “sausage digits.” It can happen to your fingers as well as your toes.
Toe dactylitis can be painful, and may affect more than one of your toes at once. Sometimes your toes stay swollen even when they’re no longer sore
Gait and posture changes. When you have AS pain and stiffness in your back or other parts of your body, you may change the way you sit, stand, and move to compensate. You might get muscle spasms or foot cramps as a result. Or you might “claw” your toes to help you balance. All these things can lead to foot pain.
How to Manage Foot Pain From Ankylosing Spondylitis
Some of the best ways to reduce foot pain and stiffness from AS are the same things you do to manage the condition itself. Which AS treatments your doctor recommends depend on several factors, including how serious your symptoms are, your general health, complications you have, and more. An AS treatment plan may include:
Exercise, physical therapy, and posture training. These techniques help ease pain and stiffness, prevent damage to your joints, and support or correct your posture.
Your exercise plan will likely include low-impact workouts that don’t worsen your symptoms as well as exercises that help prevent falls. You could also benefit from mind-body exercises like tai chi, yoga, and Pilates for relaxation and pain relief.
Talk to your doctor before you start any exercise program.
Medications. Your doctor might recommend nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen to reduce inflammation and manage pain and stiffness. You could be on these medications for weeks to months.
In some cases, your doctor will prescribe other medications, such as:
- Glucocorticoid injections (steroids)
- Disease-modifying antirheumatic drugs (DMARDs) like sulfasalazine and methotrexate
- Anti-tumor necrosis factor (TNF) medications like infliximab (Remicade), adalimumab (Humira), and etanercept (Enbrel, Erelzi, Eticovo)
- Anti-interleukin 17 medications like secukinumab (Cosentyx) and ixekizumab (Taltz)
- Tofacitinib (Xeljanz), a type of drug known as a Janus kinase (JAK) inhibitor
- Opioids (narcotics)
Your doctor could also refer you to a podiatrist to deal with foot issues due to AS. A podiatrist is a doctor who specializes in treating the foot, ankle, and lower leg. They can advise you on measures like taping, splints, footwear, and orthotics to relieve foot pain. They may also recommend exercises and stretches for your specific foot problem.
What Can I Do at Home?
There are a few things you can do at home to reduce foot pain:
- Apply ice to the painful area for about 20 minutes at least four times a day.
- Rest your feet as often as you can. Limit how often you do high-impact exercises like jumping or running. But try not to be completely inactive for long periods. This can lead to stiffness and worsen the pain.
- Do stretches that engage your calf, ankles, and toes. For plantar fasciitis, try rolling a tennis ball under the arch of your foot. For Achilles tendonitis, stand facing a wall with one knee bent and the other knee straight with the heel on the floor. Gently push your hips toward the wall until you feel a calf stretch. Do these moves slowly, and stop if they worsen your pain.
- Avoid wearing slippers or walking barefoot. Wear protective footwear like athletic shoes or other shoes with arch support and cushioned soles.