Home > Subtypes of CAPS > FCAS Facts


Facts You Can Use: FCAS

Connect with the CAPS community

We can help you make all the right connections.

  • CAPS point Locate other CAPS patients and caregivers
  • CAPS point Find CAPS support
  • CAPS point Share inspirational stories
  • CAPS point Find doctors who treat CAPS
  • CAPS point If you treat CAPS, become a part of the doctor finder
CAPS doctor finder

Find a local doctor who treats CAPS

Check CAPS symptoms

Find out if your symptoms indicate CAPS.

Familial Cold Autoinflammatory Syndrome (FCAS) is the most common subtype of CAPS (Cryopyrin-Associated Periodic Syndromes) in the United States. Most people with FCAS face difficulty in daily life; however, the rare genetic disease doesn’t seem to shorten their lives. This condition is quite rare. In fact, fewer than 1 in 1 million people have FCAS. However, this is an inherited condition, meaning that it can be passed to children from an affected parent.

Symptoms of FCAS normally show up at birth or in childhood and continue from there. It has many symptoms in common with the other subtypes of CAPS, including Muckle-Wells Syndrome (MWS). These include

  • Rash
  • Headache
  • Fever or chills
  • Feeling tired
  • Sore or red eyes
  • Muscle pain
  • Joint pain

FCAS skin rash appears 30 minutes to 2 hours after exposure to cold

Some people experience an FCAS-related rash almost daily. The rash can spread and worsen during episodes. About 4 to 6 hours after exposure, a person with FCAS generally develops a low-grade fever, painful red eyes, and pain in the extremities. Symptoms of this genetic disease may also include sweating, extreme thirst, and nausea.

Usually, FCAS symptoms disappear overnight or in less than 24 hours

In addition to FCAS treatment, the following may help ease your symptoms:

  • Dress warmly with extra layers of clothing
  • Drink hot beverages
  • Soak in a warm bath
  • Stay in warm places
  • Cover up with a blanket

Like the other genetic disease subtypes of CAPS, FCAS is caused by abnormalities in a gene called NLRP3. This gene normally helps the body develop a protein called cryopyrin. Cryopyrin allows the body to deal with inflammation.