Cryopyrin-Associated Periodic Syndromes (CAPS)

Medically Reviewed by Sabrina Felson, MD on September 09, 2022
Written by Stephanie Watson
4 min read

Cryopyrin-associated periodic syndromes (CAPS) are a group of rare autoinflammatory diseases that cause problems with your immune system. That’s what protects you from infection and other germs. When it’s not working the right way, it attacks your body instead and triggers inflammation. Symptoms can include a rash, fever, joint pain and swelling, and red eyes.

There are three CAPS:

Familial cold autoinflammatory syndrome (FCAS). Cool or cold temperatures trigger a rash. Other symptoms include fever and joint pain. FCAS is the least severe syndrome. It usually doesn't cause any long-term damage to your body.

Muckle-Wells syndrome (MWS). Cold temperatures also trigger this syndrome, along with stress and exercise. MWS doesn't cause as much damage as NOMID, but symptom flares can be severe. You may lose your hearing.

Neonatal onset multisystem inflammatory disease (NOMID). This is the most serious and least common syndrome. It starts right after birth and causes inflammation in many organs. Doctors sometimes call it chronic inflammatory neurological cutaneous articular syndrome (CINCA). NOMID sometimes leads to severe damage to the brain, eyes, and other organs if you don't treat it.

A mutation, or change, in a gene called NLRP3 is what causes CAPS. This gene carries the instructions to make the protein cryopyrin. Normally, cryopyrin helps make a substance called interleukin-1 (IL-1) to help your body fight infections.

Cryopyrin doesn't work the way it should when you have CAPS. It tells your body to make too much IL-1. This is what triggers inflammation.

You need a mutated gene from only one parent to get CAPS. Sometimes a parent doesn’t pass the gene down -- it changes on its own before you’re born.

A bumpy rash that doesn't itch is the main symptom of CAPS. It usually shows up right after birth and covers the whole body. Some people always have the rash, but it gets worse during symptom flares. Other symptoms depend on which syndrome you have.

FCAS symptoms include:

  • Fever
  • Eye swelling
  • Chills
  • Joint pain
  • Nausea
  • Headaches

These symptoms last for 1-2 days.

MWS symptoms come and go. They include:

  • Rash
  • Fever
  • Chills
  • Red eyes
  • Joint pain
  • Severe headache
  • Hearing loss
  • Nausea
  • Belly pain

Each episode lasts for 1-3 days. Children with MWS can partly or totally lose hearing by the time they reach their teenage years.

NOMID symptoms include:

  • Headache
  • Bulging eyes
  • Joint pain and swelling
  • Vomiting
  • Blindness
  • Hearing loss

Without treatment, a protein called amyloid can build up in your joints and organs, like the kidneys. It damages them over time.

The doctor will ask about your health history and whether anyone in your family has CAPS. They’ll also look at your body. You may need these tests:

Blood and urine tests. Doctors check your blood for signs of inflammation, like extra white blood cells or a substance called C-reactive protein. Large amounts of protein in your urine can also be a sign of CAPS.

Skin biopsy. This is when your doctor takes a small sample of your skin to check for extra white blood cells.

Genetic test. It shows whether your NLRP3 gene changed. But sometimes this gene is normal in people with CAPS.

Eye and ear exam. The doctor might do these tests if CAPS affects your sight or hearing.

Lumbar puncture. This test takes a small amount of fluid from your spine. Your doctor checks it for substances that signal inflammation.

Magnetic resonance imaging (MRI). This test shows detailed pictures of the inside of your body. It can show problems with your brain and inner ears.

It helps to write down a list of questions and take it with you to your doctor's appointment. Some questions you might want to ask are:

  • What kind of CAPS do I (or my child) have?
  • What symptoms does my type cause?
  • What treatments do you recommend? How will they help?
  • What are the possible side effects of treatment?
  • What can I do at home to relieve symptoms?
  • What follow-up tests will I need, and when will I need them?
  • Should I see a genetic counselor?

 

It's important to start treatment early. That’s because doctors generally can’t fix damage to your eyes, ears, bones, or brain after it happens.

Three medicines block IL-1 and help calm inflammation. They are:

  • Anakinra (Kineret)
  • Canakinumab (Ilaris)
  • Rilonacept (Arcalyst)

Your doctor might also recommend:

  • Splints to treat joint pain and swelling
  • Physical therapy
  • NSAIDs, steroids, or methotrexate to bring down a fever and ease inflammation
  • Hearing aids
  • Surgery to fix joint damage

 

If cold temperatures trigger symptoms, avoiding air conditioning and living somewhere warm can help. These stress-relieving practices may help, too:

  • Meditation
  • Deep breathing exercises
  • Yoga

You should also try to:

  • Get enough sleep.
  • Eat healthy.
  • Avoid smoking, alcohol, and processed foods.

 

There’s no cure for CAPS, but there are ways to help you or your child manage symptoms. Children who start treatment early can avoid problems like hearing and vision loss. Many people with CAPS are able to lead normal lives.

A genetic counselor can help you understand how CAPS might affect your children or other family members.

Ask your doctor if they know of any CAPS support groups. This makes it easier to connect with other people who have it. You may be able to find online or in-person support groups, depending on where you live.

Tell your doctor if CAPS is causing symptoms of depression or anxiety. They can help you find a therapist or other mental health professional to talk with about what you’re feeling and how to manage.