What is Lyme disease?

Lyme disease is an infection caused by the bite of an infected tick. The tick is so small that you may not notice the tick or its bite. Because not all ticks are infected, a bite does not always result in Lyme disease. Even if the tick is infected, it may not transfer the disease to you. It is important to note that the longer the infected tick is attached to your skin, the greater your risk of getting Lyme disease.

The disease often begins as a skin rash and, if left untreated, can cause serious nerve or heart problems as well as a disabling type of arthritis.

You should be aware of tick bites while traveling outside the U.S. as well, because this infection has been found on all continents except Antarctica.

How does it occur?

The organism that causes Lyme disease is Borrelia burgdorferi, which is transferred to human beings by the bite of a small tick. These ticks are found in vegetation and on animals in woodlands, grasslands, and marshlands.

Lyme disease is spread in the wild by birds, mice, raccoons, and deer. Domestic animals such as cats, dogs, horses, and cows can also carry the infected ticks to places where people live.

Most infections occur during the summer when you are most likely to be exposed to ticks. Hikers, campers, hunters, and people living in wooded or rural areas are at a high risk for Lyme disease.

What are the symptoms?

Lyme disease is hard to diagnose because its symptoms can vary greatly from person to person. However, if left untreated, Lyme disease may progress through these three general stages:

Stage 1:

Three to 32 days after the bite of an infected tick a skin rash, called a bull's-eye or target rash, occurs at the site of your bite. The rash begins as a red, flat or raised area and slowly expands after several days, often in a circular fashion. Often the center clears. Less often the rash may blister or scab in the center. Although the rash can be located anywhere, the thigh, groin, and armpit are common sites. The rash is warm but not painful.

Although most infected people will develop a rash, you may lack or overlook this symptom.

Other symptoms of early Lyme disease may include a flu-like illness, with or without:

• fatigue and extreme drowsiness

• pain or stiffness in muscles of joints

• a bad headache

• slight fever

• mild neck stiffness

• jaw discomfort

• chills.

Less common symptoms of early Lyme disease may include:

• conjunctivitis (inflammation of the lining of the eye)

• iritis (inflammation of the iris - or colored part - of the eye)

• sore throat

• cough

• testicular swelling.

Even if you haven't been treated, the early symptoms usually improve or disappear within several weeks. Fatigue, drowsiness, and sometimes vague musculoskeletal pain, however, may last for months after the rash has gone.

Stage 2:

After several weeks to several months, about 15% of people develop neurologic problems, which may include:

• meningitis (inflammation of the covering of the brain and spinal cord)

• encephalitis (inflammation of the brain)

• cranial neuritis (inflammation affecting the cranial nerves, which are attached to the brain and pass through the openings of the skull); for example, Bell's palsy (facial paralysis) on one or both sides of the face.

Within several weeks after onset of illness, about 8% of people develop heart problems, including carditis (inflammation of the heart) and problems with the rhythm of the heart.

During this stage, you may have pain in your joints, tendons, muscles, or bones, usually without joint swelling. These symptoms usually disappear within a few weeks.

Stage 3:

Within weeks to two years after the beginning of infection, about 60% of people develop arthritis, with joint pain and swelling. The knee is the most commonly affected joint.

In stage 3 you may have bouts of episodic arthritis or chronic (persistent) arthritis and, much less common, chronic neurologic or skin diseases.

Later nervous system symptoms associated with Lyme disease may include:

• numbness or tingling in hands and feet

• difficulty in concentrating

• weakness in arms or legs

• depression.

Pregnant and nursing women:

If you are pregnant and have Lyme disease, it is possible that you may pass the disease to your baby. Although such spread is rare, you should call your doctor immediately if you are pregnant and have symptoms of Lyme disease. Also, if you are a nursing mother and are bitten by a tick and develop symptoms, contact your doctor for advice.

How is it diagnosed?

Lyme disease can be difficult to diagnose. To diagnose the disease, your doctor will review your symptoms, take a medical history, and examine you.

Your doctor may also order blood tests. He or she may take a sample of cerebrospinal fluid for analysis if you have neurologic symptoms.

How is it treated?

Treatment for Lyme disease is antibiotic therapy. If Lyme disease is diagnosed before your joints are inflamed, your doctor will prescribe antibiotics, such as tetracycline, for 10 to 20 days. Penicillin may be prescribed for pregnant women and young children for 2 to 4 weeks.

In stage 1 disease, regardless of the antibiotic given, almost half the people with Lyme disease have minor recurrences of headaches, musculoskeletal pain, or fatigue. Eventually there is complete recovery.

Further treatment may be required for stage 2 or stage 3 disease, and especially if you have infection or inflammation of the heart, central nervous system, or joints.

How long will the effects last?

The symptoms may occur in cycles lasting a week or so. If the disease is not diagnosed and treated, the symptoms can last for several years and the symptoms will gradually decline. Permanent effects depend on the extent of the disease and your individual situation. Meningitis, which can strike in Stage 2, can be life-threatening.

How can I take care of myself?

To help take care of yourself, follow the full course of treatment prescribed by your doctor. You need to take all of your antibiotic therapy for it to be effective. Do not stop taking antibiotics because you start to feel better or your symptoms disappear. If you have problems tolerating your antibiotic, call your doctor for a different prescription.

What can be done to help prevent Lyme disease?

To avoid getting Lyme disease follow these measures:

• Be aware of areas where ticks can be found. Do not walk, camp, or hunt in the woods of tick-infested areas without precautions.

• In overgrown countryside, try to stay near the center of trails.

• When you are outdoors wear long-sleeved shirts and pants tucked into socks if possible. Light-colored clothing makes it easier to find the small tick before it bites. A hat may help, too.

• Use approved tick repellents on exposed skin and clothing. Don't spray them repeatedly over long periods, don't use excessive amounts, and don't spray on open wounds or rashes. Wash the spray from hands. Be careful with children because the repellents can make them ill.

• Treat household pets for ticks and fleas. Check pets after they've been outdoors.

• Brush off clothing and pets before entering the house.

• Undress and check for ticks. They usually crawl about for several hours before biting.

• Check your clothes, too. Wash them immediately to remove any ticks.

• Shower and shampoo after your outing.

• Inspect any gear you were carrying.

• Remove an attached tick with fine-tipped tweezers by gripping it as close to your skin as possible and gently pulling it straight away from you until it releases its hold. Don't twist it as you pull, and don't squeeze its bloated body. Thoroughly wash your hands and the bite area and apply an antiseptic such as rubbing alcohol.

• If you spend much time hiking, you may want to invest in a pair of tick tweezers available at many sporting goods stores as part of your first-aid kit.

• If you discover a bite, see your doctor.

• Check for a rash. Check for other symptoms until about eight weeks after the bite.