Why Ankylosing Spondylitis Flares Happen and What Can Help

Medically Reviewed by Tyler Wheeler, MD on July 27, 2022
3 min read

Ankylosing spondylitis (AS) flare-ups can be common. Researchers and doctors don’t have an official definition of what happens in an AS flare. But if you have one, you know it based on how you feel.

Your flare-up may feel different than someone else’s. One study looked at flares as generalized or localized, based on whether they affected the whole body or just one area. The most common symptoms were: 

  • Pain
  • Extreme tiredness
  • Not being able to move well
  • Changes in mental health, like depression

Some also had other symptoms, such as feeling like they had the flu, sweating, and a fever. People said their joints felt hot and burning. Muscle spasms and more sensitivity also happened.

More morning stiffness may be a sign that a flare-up is coming. Sometimes, you could have stiffness and fatigue throughout the day.

There are many causes. More inflammation is partly to blame. Other ankylosing spondylitis triggers could play a role, too.

You may feel worse because of conditions you might have in addition to AS. Or you might have an injury or an infection. A weather change could even be the cause. And a flare might mean that in some way, your treatment isn’t working well enough.

You also set yourself up for a flare if you stop taking your medication or accidentally miss doses.

Still, some flares are due to random changes in how active your disease is, regardless of whether you’re on meds or not. Experts aren’t sure why that is.

Some people living with AS have their own ideas about why they might get flares. One small study found that people with the condition thought stress and “overdoing it” triggered their flare-ups.

When you have a flare, you may need pain medication. If you take NSAID drugs, your doctor may prescribe a higher dose.

If you take a biologic, the doctor may change the dose or the drug itself. They might do that if they think your medication isn’t working as well for you as it used to.

Other things that may help during a flare are:

  • Sleep
  • Relaxation
  • Gentle exercise or stretches
  • Hot and cold therapy
  • A warm bath or shower
  • Massage

Once you know what works when your AS is more intense, you can create a list so you’re ready if it happens again.

AS flares tend to be unpredictable. You may be able to help prevent some of them by knowing your possible triggers, like too much stress or activity. But flares can also happen for reasons outside of your control.

Your rheumatologist can help you make a plan in case a flare happens. For instance, they can weigh in on whether to adjust how much of your medication you take during a flare and what other medications might help if you need extra help managing symptoms. Be sure to ask about:

  • What dose you should take, including the maximum amount
  • How often and how long you can use it

Take notes on what your doctor says, and make sure you can find these instructions later. When you do use medication, write down when you take it and how much you have, so you can stay within the guidelines your doctor gave you. And tell your doctor about everything you take, including over-the-counter medications.

Reach out to your doctor if your flare:

  • Doesn’t improve with treatment after 7 days and you need help with it.
  • Is more intense or different than normal -- for example, it causes very strong back pain.

You should also track your flare-ups and tell your doctor if you start to have more of them or if they last longer.