Updated September 29, 2026
Trying to distinguish between autoinflammatory diseases can be difficult. Many share the same features: fever, abdominal pain, rashes, and blood tests showing inflammation. For patients and families, these overlapping symptoms can mean years of appointments without a clear explanation.
Sometimes, the most useful clue is the pattern. How long do the episodes last? What happens along with the fever? Does anyone else in the family have similar symptoms?
In TRAPS, prolonged episodes of fever, muscle pain, and a rash that moves across the body can help point us in the right direction.
What is TRAPS?
TRAPS stands for tumor necrosis factor receptor–associated periodic syndrome. It is a rare autoinflammatory condition associated with disease-causing changes in TNFRSF1A, a gene involved in regulating inflammation.
TRAPS was once called “Hibernian fever” after its recognition in an Irish family. However, it affects people of many backgrounds.
It often follows an autosomal dominant inheritance pattern: a parent carrying a disease-causing variant has a 50% chance of passing that variant to each child. But symptoms and severity can vary, and some people have a new genetic change without an affected parent. Learn more about TRAPS genetics.
What symptoms can occur?
Episodes can include:
- Fever lasting several days to several weeks.
- Muscle pain, sometimes with a red rash that moves along an arm or leg.
- Abdominal pain.
- Joint pain.
- Chest pain.
- Red eyes or swelling around the eyes.
Symptoms often begin in childhood, but they can first appear in adulthood. Episodes commonly last about 5–25 days, although shorter attacks occur. The timing is not necessarily predictable, despite the word “periodic” in the name.
Not everyone has every feature. Some people also have ongoing inflammation between obvious attacks. GeneReviews describes the range of TRAPS symptoms.
What did the international registry teach us?
A study published in 2014 described 158 patients in the Eurofever/EUROTRAPS registry. Attacks lasted approximately 11 days, and patients experienced an average of about 70 symptomatic days per year. Many adults had waited years for a diagnosis.
For me, the length of these episodes—and the combination of rash and limb pain—really helped distinguish TRAPS from other autoinflammatory conditions.
These numbers describe that study population. They are not requirements for diagnosis or predictions of what every patient will experience. Read the registry study.
How is TRAPS diagnosed?
Doctors bring together the symptom pattern, examination, blood tests, family history, and genetic testing. A disease-causing TNFRSF1A variant can help establish the diagnosis when the clinical features fit.
Genetic results need careful interpretation alongside the symptoms. A finding on a genetic report does not automatically explain someone’s illness, and the absence of a known family history does not rule out TRAPS.
Evaluation by a rheumatologist or another clinician experienced in autoinflammatory disease can help clarify the diagnosis. More about diagnosis.
How is TRAPS treated?
Medicines that block interleukin-1 (IL-1), an inflammatory signaling protein, are central to treatment. These include canakinumab and anakinra. The choice depends on the patient’s disease and circumstances.
Corticosteroids can help during an attack, but they are not sufficient for long-term prevention of complications. Treatment overview.
The goal is to control both symptoms and inflammation. Follow-up can include blood tests for inflammation, urine testing for protein, and attention to growth, school, work, and everyday functioning. Feeling better is important, but laboratory monitoring also helps show whether inflammation is controlled. EULAR/ACR guidance on treatment and monitoring.
Why does early recognition matter?
Persistent inflammation can lead to AA amyloidosis, a buildup of abnormal protein that can damage organs, particularly the kidneys.
The 2014 registry study reported amyloidosis in about 10% of its participants. That historical figure should not be interpreted as the expected risk for every person diagnosed and treated today.
Controlling inflammation and monitoring for complications are important parts of care. Our challenge remains to recognize TRAPS earlier and help patients spend less time ill and more time living their lives.