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Autoimmune & autoinflammatory

Periodic fever syndromes overview

Recurrent fevers that arrive in stereotyped episodes with well intervals between are the signature of the autoinflammatory periodic fever syndromes - genetic conditions increasingly treatable with targeted drugs.

Key points

The essentials at a glance.

What to look out for, which tests matter, who treats it, and what usually happens next.

  • Think of them when fevers recur in similar episodes over months to years, with complete recovery in between

  • Major named syndromes: FMF, TRAPS, CAPS, mevalonate kinase deficiency, and non-genetic PFAPA

  • Episode diaries - duration, interval, accompanying symptoms - do more diagnostic work than any single blood test

  • Genetic panel testing confirms most inherited forms; raised inflammatory markers during attacks support the picture

  • The stakes include amyloidosis from decades of uncontrolled inflammation - effective prophylaxis prevents it

Understanding it

About Periodic fever syndromes overview.

These are diseases of the innate immune system firing without instruction: inflammasomes misassemble, interleukin-1 pours out, and the body stages a full febrile illness - fever, rash, serositis, joint and muscle pain - without any infection to justify it. Each syndrome has a rhythm: FMF attacks are short and peritonitic; TRAPS episodes run longer with migrating limb pain; CAPS flares follow cold exposure; and the pattern, more than the severity, is what points to the gene.

Adults carry these diagnoses too - milder variants and decades of mislabelled recurrent infections or seronegative arthritis are common back-stories - and the therapeutic payoff is real, since colchicine and IL-1 blockers such as anakinra and canakinumab can abolish attacks and, crucially, halt the amyloid risk. The UK routes suspected cases to specialist autoinflammation centres; a documented fever diary and inflammatory markers captured during an attack are the tickets that make that referral stick. In many parts of the UK, a routine NHS referral to the relevant specialist clinic currently means waiting many months - sometimes more than a year for the rarest conditions - whereas an initial appointment with a private consultant is typically available within around two weeks, with investigations arranged soon after.

Frequently asked

Common questions about Periodic fever syndromes overview.

Quick, plain-English answers to what people ask us most.

  • What are periodic fever syndromes?

    Periodic fever syndromes are a group of rare conditions causing recurrent episodes of fever, often with additional symptoms like rash, joint pain, or abdominal pain, occurring in a cyclical or unpredictable pattern. Many are linked to overactivity of the innate immune system.

  • What causes periodic fever syndromes?

    Several are genetic, caused by mutations affecting how the immune system regulates inflammation, such as Familial Mediterranean Fever or TRAPS. Others, like PFAPA, have no clearly identified genetic cause.

  • What are the symptoms?

    Recurrent fever episodes lasting days, often accompanied by mouth ulcers, sore throat, swollen glands, joint pain, abdominal pain, or rash, are typical. Between episodes, most people feel completely well.

  • Are periodic fever syndromes serious?

    Most are not immediately dangerous, but recurrent inflammation can, in some genetic forms, lead to long-term complications such as amyloidosis if untreated. Getting an accurate diagnosis and treatment reduces this risk substantially.

  • Are periodic fever syndromes genetic?

    Many are, including Familial Mediterranean Fever, TRAPS, and Hyper-IgD syndrome, which are caused by specific inherited gene mutations. Genetic testing can confirm these diagnoses, though some periodic fever syndromes are not inherited.

  • Can periodic fever syndromes be treated?

    Yes, treatment depends on the specific syndrome but can include colchicine, anti-inflammatory biologic medications, or in children with PFAPA, tonsillectomy in some cases. Many people achieve good control of symptoms with the right treatment.

  • How are periodic fever syndromes diagnosed?

    Diagnosis combines the pattern and timing of symptoms, blood tests during and between episodes, and often genetic testing for the known hereditary syndromes. Because they are rare, referral to a specialist in autoinflammatory conditions is often needed.

  • How long do the fever episodes last?

    Episode length varies by syndrome, from a few days in Familial Mediterranean Fever to longer stretches in others, typically recurring every few weeks to months. Between episodes, symptoms usually resolve completely.

  • Periodic fever syndromes vs recurrent infections — what's the difference?

    Recurrent infections usually have an identifiable microbial trigger and respond to antibiotics or antivirals, whereas periodic fever syndromes are driven by the immune system itself and don't respond to antimicrobial treatment. Blood tests can help distinguish between the two.

  • When should I see a doctor, and how quickly can I be seen privately?

    See a doctor if fever episodes are recurring in a pattern, especially alongside rash, joint pain, or a family history of similar symptoms. Private specialist assessment can typically be arranged within about two weeks, much faster than the often lengthy NHS pathway for rare disease referrals.