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Familial Mediterranean fever is an inherited inflammatory disorder usually occurring in people of Mediterranean origin — including Sephardic Jews, Arabs, Armenians and Turks — but may affect any ethnic group. A rare disorder, familial Mediterranean fever (FMF) is characterized by recurrent fevers and painful inflammation of your abdomen, lungs and joints.

Familial Mediterranean fever is typically diagnosed during childhood. While there's no cure for this disorder, you may be able to relieve your signs and symptoms of familial Mediterranean fever or prevent them altogether by adhering to your treatment.

Signs and symptoms of familial Mediterranean fever usually begin during childhood. In fact, 80 percent to 95 percent of all people diagnosed with FMF are younger than 20 years old. The signs and symptoms, collectively referred to as "attacks," often occur with little warning. Generally, the attacks last two to three days, reaching peak intensity within the first 12 hours. Typical signs and symptoms may include:

• A sudden fever, ranging from about 100 to 104 F
• Abdominal pain
• Chest pain
• Achy, swollen joints
• Constipation followed by diarrhea
• A rash on your legs, especially below your knees

Less common signs and symptoms may include:

• Muscle aches
• Inflammation of the female reproductive organs (pelvic inflammatory disease)
• A swollen, tender scrotum
• Inflammation of your blood vessels (vasculitis)

Attacks usually occur sporadically, although some people report that vigorous exercise or stress provokes their attacks. Symptom-free periods may be as short as a week or as long as months. Between attacks, you'll likely feel normal.

The cause of familial Mediterranean fever is a gene defect on chromosome 16 (each person normally has 46 chromosomes, in 23 pairs). Although it's not certain exactly how this defect causes familial Mediterranean fever, it may be that people with a mutation in this gene don't make a protein that inhibits the inflammatory response in certain parts of the body.

Familial Mediterranean fever is inherited as an autosomal recessive trait, meaning that you must inherit the mutated gene from each parent in order to develop the condition.

If you're of Mediterranean descent or you have a relative with familial Mediterranean fever, you're at higher risk of developing the disorder than are people without either of those two characteristics. Men are also more likely to be affected than are women.

See your doctor if you have a sudden fever accompanied by pain in your abdomen, chest and joints, so that your doctor can determine the cause.

Familial Mediterranean fever is usually well controlled by the medication colchicine. Consult your doctor if you experience any of the following:

• Diarrhea, nausea or vomiting. Side effects of colchicine are usually mild, but these signs and symptoms could indicate that your medication dose may need to be adjusted.
• Chronic pain. You may want to see a doctor who specializes in pain management if you have persistent pain that's not relieved by your medication.
• Ongoing attacks. If carefully adhering to colchicine therapy isn't preventing your attacks, talk to your doctor about other treatment options, such as dietary changes.

If you experience sudden worrisome symptoms, such as shortness of breath or passing out, call 911 or emergency medical help.

No specific test is available to detect familial Mediterranean fever. After ruling out other diseases, your doctor makes a diagnosis based on a combination of the following factors:

• Signs and symptoms. The most common signs and symptoms of familial Mediterranean fever are an unexplained, abrupt fever and severe pain in your abdomen, chest or joints. The abdominal pain may mimic appendicitis (inflammation of the appendix). These problems tend to improve spontaneously and then recur some time later.
• Family history. A family history of familial Mediterranean fever increases your likelihood of developing the condition because the genetic mutation is passed from parents to their children. About half of the people with FMF have a family history of the condition.
• Ethnicity. Familial Mediterranean fever most often develops in people of Mediterranean origin, including Sephardic Jews, Armenians, Turks, North Africans, Arabs, and less frequently, Greeks and Italians. The condition has also been diagnosed in other ethnic groups, including Ashkenazi Jews in the United States, so FMF can't be diagnosed based on ethnicity alone.
• Blood tests. During an attack, blood tests may show elevated levels of certain markers that indicate an inflammatory condition in your body. An elevated level of white blood cells, which fight infections, is one such marker.
• Genetic testing. This test may determine if your genes have mutations that are associated with familial Mediterranean fever. Doctors don't commonly use genetic testing as a diagnostic tool because the available tests don't assess for all the gene mutations associated with the disorder. However, genetic testing may help confirm a diagnosis of FMF in people with atypical signs or symptoms.

Most complications of familial Mediterranean fever result if it's not treated or if it's treated irregularly:

• Amyloidosis. This is the most common complication arising from untreated familial Mediterranean fever. Amyloidosis refers to a condition in which a protein called "amyloid A" deposits in your organs. In cases of FMF, amyloidosis often affects the kidneys, which may cause a kidney disorder called nephrotic syndrome.
• Nephrotic syndrome. Nephrotic syndrome results when your kidneys' filtering systems (glomeruli) are damaged. People with this condition may have swollen feet and hands and lose large amounts of protein in their urine. Nephrotic syndrome can lead to blood clots in your kidneys (renal vein thrombosis) or kidney failure.
• Infertility. Inflammation caused by familial Mediterranean fever may also affect your reproductive organs. About one-third of the women with this condition are infertile, and 20 percent to 30 percent of those who become pregnant experience miscarriages.
• Chronic arthritis. Chronic arthritis develops in 5 percent of the people with familial Mediterranean fever. In some cases, hip or knee joint replacement surgery may be necessary.
• General discomfort. Familial Mediterranean fever can be a painful condition interfering with the flow of daily life. If your symptoms are intolerable, your doctor might recommend strong pain medication (narcotics) to help make you more comfortable.

The most successful treatment for familial Mediterranean fever is a drug called colchicine. There's no cure for the condition.

• Colchicine therapy. Colchicine is a drug, usually taken as a pill, which reduces inflammation in your body. Some people might need to take just one dose a day, while others might require multiple doses. People who are able to "predict" an impending attack are often able to stop those attacks before they start by taking colchicine. However, taking colchicine after your symptoms appear is not effective.

  Sticking to your colchicine schedule is important because the drug will likely reduce the frequency and intensity of your symptoms. It also lowers your risk of complications, especially amyloidosis. Colchicine can cause side effects such as pain, tingling or numbness in your hands or feet, or muscle weakness, especially in older men who are heavy drinkers or whose kidneys aren't functioning properly. However, colchicine therapy is generally considered safe, even when taken over the course of years.

• Dialysis or kidney transplantation. Before colchicine therapy was developed in 1972, people with familial Mediterranean fever often required dialysis, a procedure that removes wastes from the blood using special equipment, or kidney transplants because their kidneys eventually failed. Today, these two therapies are usually reserved for people who don't adhere to therapy or who can't tolerate colchicine.

In addition to medical therapy, you may find that the frequency and the severity of your symptoms lessen as you age or if you become pregnant. It's not certain why symptoms may improve at either of these times, but it may be related to changes in your immune system.

Familial Mediterranean fever can't be prevented. However, you can relieve your signs and symptoms and prevent complications by adhering to the colchicine regimen recommended by your doctor.

If you have familial Mediterranean fever, try these tips to help you manage your condition:

• Take your medication on schedule. Sticking to your colchicine regimen is crucial for relieving your symptoms and preventing complications. Taking colchicine on a regular schedule may also reduce side effects of the medication. Tricks to help you remember to take your medicine — such as taking it right after you brush your teeth or tacking a note to the refrigerator door — may prove helpful.
• Discuss pregnancy with your doctor. If you'd like to start a family, talk to your doctor about how you can increase the chances that your baby will be healthy. Fortunately, colchicine therapy isn't associated with an increased risk of infertility or of abnormalities in a developing baby.
• Fine-tune your diet. Some people with FMF notice that their attacks are lessened by following a low-fat diet. One side effect of colchicine therapy is lactose intolerance, so if you experience abdominal discomfort, such as bloating, a lactose-free diet may improve your symptoms.