Familial Mediterranean Fever (FMF)

What is Familial Mediterranean Fever (FMF)?

Familial Mediterranean fever (FMF) is an inherited condition that causes repeated episodes of fever together with painful inflammation of the lining of the abdomen, chest, or joints. Inflammation is the body’s natural response to injury or infection, but in FMF it switches on without any infection being present. For this reason FMF is grouped with the autoinflammatory diseases, a family of conditions in which the innate immune system (the body’s first-line, non-specific defense) becomes overactive on its own.

The word “familial” reflects that the condition runs in families, and “Mediterranean” reflects that it is most common in people whose ancestors came from the eastern Mediterranean and surrounding regions, including people of Turkish, Armenian, Arab, Sephardic Jewish, and North African descent. It does, however, occur in people of many other backgrounds, and a lack of known Mediterranean ancestry does not rule it out.

FMF is a lifelong condition. Symptoms usually begin in childhood or adolescence, and in most people the first attack occurs before the age of 20. Between attacks, people generally feel well. With appropriate long-term treatment, many people with familial Mediterranean fever are able to lead full and active lives, although the condition needs ongoing medical follow-up. In many hospitals, including Acibadem, FMF is managed mainly by rheumatologists, who are doctors specializing in inflammatory and autoimmune conditions, often working with pediatricians, nephrologists (kidney specialists), and geneticists.

Symptoms of familial Mediterranean fever

Familial Mediterranean fever symptoms come in attacks, also called flares, that typically last one to three days and then settle on their own. Attacks can occur every few weeks, every few months, or much less often, and the pattern is often unpredictable. Common features include:

• Fever that starts suddenly, is often high, and may be accompanied by chills
• Abdominal pain, often severe and spread across the whole abdomen, sometimes with a rigid, tender belly that can resemble appendicitis or another surgical emergency
• Chest pain on one side that worsens with breathing, caused by inflammation of the lining around the lungs (pleurisy)
• Joint pain and swelling, usually in one large joint such as the knee, ankle, or hip
• A red, warm, painful skin rash, most often on the lower leg, ankle, or foot, sometimes described as resembling a skin infection (erysipelas-like rash)
• Muscle aches, particularly in the legs, sometimes brought on by exercise
• Constipation during an attack, which may be followed by loose stools as it resolves
• Fatigue and general unwellness around the time of an attack

Not everyone has every symptom, and the pattern can differ from one person to another and even from one attack to the next in the same person. Some people have attacks dominated by abdominal pain, others mainly by chest or joint symptoms. Young children may present with fever alone before the more typical features appear. In a smaller group, joint inflammation can last for weeks rather than days, and in men, inflammation of the scrotum can occasionally occur.

Some people notice a vague warning phase, sometimes called a prodrome, in the hours before an attack, with mild discomfort, irritability, or a change in appetite. Many people also identify possible triggers such as emotional stress, physical exertion, menstruation, cold exposure, or a recent infection, although attacks frequently occur without any obvious trigger.

The most serious long-term complication of untreated or undertreated FMF is amyloidosis. This is a condition in which a protein called amyloid A, produced in large amounts during ongoing inflammation, builds up in organs, most often the kidneys. Kidney amyloidosis can cause protein to leak into the urine and, over time, may lead to kidney failure. Amyloidosis often develops silently, without attacks feeling worse, which is one of the main reasons that regular monitoring matters even when a person feels well.

Causes and risk factors

Familial Mediterranean fever causes are genetic. The condition is caused by changes (variants) in a gene called MEFV. This gene carries the instructions for making a protein called pyrin, which helps regulate inflammation in certain white blood cells. When pyrin does not work correctly, these cells release inflammatory signals too easily, leading to the episodes of fever and pain that define the disease.

FMF is most often inherited in an autosomal recessive pattern. This means that a person usually needs to inherit an altered copy of the MEFV gene from each parent to develop the typical condition. Parents who each carry one altered copy generally have no symptoms themselves and may not know they are carriers. When both parents are carriers, each child has a chance of inheriting two altered copies, one altered copy (becoming a carrier), or none. However, the genetics are not always straightforward. Some people with only one altered copy do develop symptoms, and some people with two altered copies remain mild or symptom-free, so doctors consider genetic results alongside the clinical picture rather than in isolation.

Risk factors for having FMF include:

• Family history of FMF or of unexplained recurrent fevers in relatives
• Ancestry from the eastern Mediterranean, Middle East, Caucasus, or North Africa, where carrier rates are higher
• Parents who are related, which increases the chance that both carry the same altered gene

Certain MEFV variants are associated with more severe disease and a higher risk of amyloidosis, while others tend to produce milder symptoms. Environmental factors do not cause FMF, but stress, infections, and other triggers may influence how often attacks occur. FMF is not contagious and cannot be caught from another person.

Diagnosis of familial Mediterranean fever

Familial Mediterranean fever diagnosis rests mainly on the pattern of symptoms over time, supported by blood tests and genetic testing. Because attacks can resemble many other conditions, including appendicitis, infections, and other periodic fever syndromes, it is common for the diagnosis to take some time, and some people have gone through emergency visits or even surgery before FMF is recognized.

Doctors typically begin with a detailed history and physical examination. They will ask about the duration and frequency of fever episodes, the exact nature of the pain, any rash or joint swelling, the age at which episodes began, ancestry, and whether relatives have similar symptoms. Keeping a written or phone-based diary of attacks can be very helpful in showing the recurring pattern.

Tests that may be used include:

• Blood tests during an attack, which usually show raised inflammation markers such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and a high white blood cell count. Serum amyloid A protein may also be measured where available.
• Blood tests between attacks, to check whether inflammation settles fully or persists silently.
• Genetic testing of the MEFV gene, using a blood or saliva sample, to look for known disease-related variants.
• Urine tests to check for protein, which can be an early sign of kidney amyloidosis.
• Imaging such as abdominal ultrasound or chest X-ray, mainly to rule out other causes of pain rather than to confirm FMF itself.
• A trial of colchicine, in selected cases, since a clear reduction in attacks with this medicine supports the diagnosis.

Doctors also use published clinical criteria that combine typical attack features, family history, ancestry, and response to treatment. It is important to know that a negative genetic test does not completely exclude FMF, because not every disease-causing variant is currently known, and a positive test in someone without symptoms does not necessarily mean the disease will develop. The overall picture, interpreted by an experienced clinician, is what leads to a confident diagnosis. Evaluation is usually coordinated through a Rheumatology Department or a pediatric rheumatology service for children.

Treatment options for familial Mediterranean fever

Familial Mediterranean fever treatment has two main goals: to prevent or reduce the frequency and severity of attacks, and to prevent amyloidosis by keeping long-term inflammation under control. There is currently no cure, but effective preventive treatment exists for the great majority of people.

Colchicine is the standard first-line medicine. It is a tablet taken every day, usually for life, that reduces the overactive inflammatory response. When taken consistently, it prevents attacks entirely or greatly reduces them in most people, and it is the treatment shown over decades to protect against amyloidosis. The dose is adjusted by the doctor according to age, weight, response, and side effects. The most common side effects are digestive, such as diarrhea, cramping, or nausea, and these can often be managed by adjusting the dose or starting slowly. Colchicine is generally considered safe for long-term use, including during pregnancy and breastfeeding in most cases, but decisions about pregnancy should always be discussed with the treating team. Some medicines, including certain antibiotics and cholesterol-lowering drugs, can interact with colchicine, so it is important that every doctor and pharmacist involved knows a person is taking it.

Biologic medicines are used for people whose attacks continue despite the highest tolerated dose of colchicine, or who cannot tolerate colchicine. These are injectable medicines that block a chemical messenger called interleukin-1, which plays a central role in FMF inflammation. Examples include anakinra and canakinumab. They are usually added to colchicine rather than replacing it, because colchicine remains important for amyloid protection. Biologic treatment requires monitoring for infections and is prescribed by specialists.

Treatment during an attack focuses on comfort. Rest, fluids, and pain relievers such as acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs) may be used as advised by a doctor. Increasing the colchicine dose during an attack is generally not helpful for stopping an attack already under way. In hospital, doctors will also make sure that a severe abdominal attack is not being confused with a true surgical emergency.

Surgery is not a treatment for FMF itself. Procedures are only relevant if a separate problem develops, such as adhesions (internal scar tissue) after repeated abdominal inflammation, or if the diagnosis is uncertain and a surgical cause of pain cannot be excluded. Rehabilitation and physical therapy are occasionally helpful for people with prolonged joint inflammation.

Monitoring is a core part of treatment. Regular visits typically include review of attack frequency, blood tests for inflammation, and urine tests for protein. If kidney amyloidosis develops, a nephrologist becomes involved, and treatment aims to control inflammation as tightly as possible to slow further damage.

Living with familial Mediterranean fever (FMF) / outlook

The outlook for people with familial Mediterranean fever has improved greatly since daily colchicine became standard care. With consistent treatment and follow-up, many people have few or no attacks and a normal life expectancy, and the risk of amyloidosis is substantially reduced. The most important factor within a person’s control is taking colchicine every day as prescribed, even when feeling well, because attacks and silent inflammation tend to return when doses are missed.

Practical steps that many people find helpful include keeping an attack diary, learning personal triggers, maintaining regular sleep and stress-management routines, and carrying a brief note or medical alert card explaining the diagnosis so that emergency staff understand the pattern of pain. Children with FMF can usually attend school and take part in sports, with a plan agreed with the school for what to do during an attack.

Genetic counseling may be offered to families, particularly when planning a pregnancy, to explain inheritance and the options for testing relatives. FMF affects each person differently, and while treatment is effective for most, some people experience persistent symptoms or side effects that require adjustments over time. Regular contact with a rheumatology team allows treatment to be tailored as circumstances change.

Frequently asked questions

What are the first familial Mediterranean fever symptoms in children?

In young children, the earliest sign is often recurrent fever without an obvious infection, sometimes with irritability or refusal to eat. Abdominal pain, chest pain, joint swelling, and the characteristic leg rash may appear later as the child grows. Because fevers are common in childhood for many reasons, a pattern of similar episodes recurring over months is what usually prompts doctors to consider FMF.

Is familial Mediterranean fever caused by something I did?

No. Familial Mediterranean fever causes are inherited changes in the MEFV gene present from birth. Nothing a parent or child did, ate, or was exposed to causes the condition. Stress, infections, or tiredness may act as triggers for individual attacks in some people, but they do not cause the underlying disease.

Can familial Mediterranean fever be cured?

There is currently no cure, because the underlying gene change cannot be reversed. However, familial Mediterranean fever treatment with daily colchicine controls the condition in most people, and biologic medicines are available for those who need them. For many people, well-controlled FMF has little day-to-day impact on their lives.

How is familial Mediterranean fever diagnosis confirmed if the genetic test is negative?

Doctors can still diagnose FMF on clinical grounds when a person has typical recurring attacks, raised inflammation markers during episodes, a compatible family history or ancestry, and a clear improvement on colchicine. Genetic testing supports the diagnosis but is not the only basis for it, because some disease-causing variants are not yet identified.

Do I need to take colchicine for life?

In most cases, yes. Colchicine is a preventive medicine, and its protective effect against attacks and amyloidosis depends on taking it continuously. Stopping it usually leads to attacks returning, and silent inflammation can build up even without symptoms. Any change in dose should be made together with the treating doctor rather than independently.

Can a person with familial Mediterranean fever have children?

Yes. Many people with FMF have healthy pregnancies and children. Colchicine is generally continued during pregnancy in most cases because uncontrolled inflammation carries its own risks, but this should always be planned with a rheumatologist and obstetrician. Genetic counseling can explain the chance of passing the gene on and the options for testing.

When to see a doctor

Anyone with repeated episodes of unexplained fever accompanied by abdominal, chest, or joint pain, especially with a family history or Mediterranean ancestry, should be evaluated by a doctor. People already diagnosed with FMF should keep their scheduled follow-up visits even when they feel well, so that inflammation and kidney function can be monitored.

Seek urgent medical care, including emergency services where appropriate, if any of the following occur:

• Severe abdominal pain that is different from usual attacks, lasts longer than expected, or comes with persistent vomiting, since a true surgical problem such as appendicitis must be excluded
• Difficulty breathing or chest pain that does not fit the usual attack pattern
• Swelling of the legs, ankles, or around the eyes, or foamy urine, which can suggest kidney involvement
• Very high fever with confusion, stiff neck, a spreading rash, or a hot, swollen joint, which may indicate infection rather than an FMF attack
• Signs of colchicine toxicity, such as severe or persistent diarrhea, vomiting, muscle weakness, or numbness, particularly after starting a new medicine
• Signs of infection while on biologic treatment, such as fever with cough, painful urination, or a wound that is not healing

These situations may be serious and should not wait for a routine appointment.