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. Many ticks do not carry Lyme disease.
Even if a tick is infected, it may not transfer the disease
to you. An infected tick that is attached for less than 36
hours is less likely to transmit infection. For these
reasons, most tick bites do not cause Lyme disease.
The disease often begins as a rash. If you don't get
treatment, the infection can cause serious nerve or heart
problems as well as a disabling type of arthritis (pain and
swelling in one or more joints caused by inflammation).
How does it occur?
Bacteria called Borrelia burgdorferi cause Lyme disease.
The disease is spread to human beings by the bite of a tiny
tick infected with the bacteria. These ticks are found in
vegetation and on animals in woodlands, grasslands, and
marshlands. Wild birds, mice, raccoons, and deer, as well
as cats, dogs, horses, and cows, can carry the infected
ticks. Ticks may climb on humans from leaf litter and
low-lying vegetation in wooded, brushy, or grassy areas. Ticks
cannot jump or fly.
People usually become infected during the summer, when they
are more likely to be exposed to ticks. Hikers, campers,
hunters, and people living in wooded or rural areas have a
higher risk for Lyme disease.
This infection has been found on all continents except
Antarctica. In the US the infection is more common in the
northern states.
What are the symptoms?
Lyme disease is hard to diagnose because its symptoms can
vary greatly from person to person. The first symptoms may
not even be noticed.
Untreated Lyme disease may progress through these 3 stages:
Stage 1:
In the first month after a bite by 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 large red spot that may
be flat or bumpy. The area of the rash feels warm, but it
is not painful or itchy. The rash slowly expands after
several days, often in a circular pattern. The center
usually clears, creating what is called a bull's-eye rash.
Sometimes the rash may blister or scab in the center. The
thigh, groin, and armpit are common sites for the rash, but
it can appear anywhere.
Although most infected people develop a rash, you may not
have this symptom, or you may overlook it.
You may feel like you have the flu, with such symptoms as:
- fatigue and extreme drowsiness
- pain or stiffness in muscles and joints
- headache
- chills and fever
- stiff neck
- jaw discomfort.
Less common symptoms of early Lyme disease are:
- inflammation of the eye, making it red
- sore throat
- cough
- in men, a swelling of the testicles.
Even if you don't get treatment, the early symptoms usually
improve or go away within several weeks. However, fatigue,
drowsiness, and sometimes vague muscle or joint pain may
last for months after the rash has gone.
Stage 2:
Several weeks to several months after the first symptoms
appear, as many as 15% of infected people may develop
problems with their nervous system. These problems may
include:
- Meningitis, which is inflammation of the covering of the
brain and spinal cord.
- Encephalitis, which is inflammation of the brain.
- Cranial neuritis, which is inflammation of the cranial
nerves. These nerves pass from the brain to other parts
of the body through openings in the skull. Inflammation
of these nerves can cause weakness or paralysis of one or
both sides of the face (Bell's palsy).
About 8% of infected people develop heart problems, such as
carditis (inflammation of the heart) and problems with the
rhythm of the heart.
During this second 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 a few weeks to 2 years after the start of the
infection, about 60% of people develop arthritis, with joint
pain and swelling. The knee is the joint most often
affected.
In stage 3 you may have temporary bouts of arthritis or
you may feel the arthritis all the time. You may have
ongoing nervous system problems, but this is less likely.
Symptoms of nervous system problems during stage 3 may
include:
- numbness or tingling in your hands and feet
- trouble concentrating
- weakness in your arms or legs
- depression.
How is it diagnosed?
Lyme disease can be hard to diagnose. Your healthcare
provider will ask about your symptoms and medical history.
He or she will examine you.
You may have a blood test for Lyme disease. Or you and your
provider may decide to start treatment without the test.
If you were recently bit by a tick, saving the tick may help
your provider diagnose your symptoms.
How is it treated?
Lyme disease is treated with antibiotics. Early treatment
can help prevent possible complications. The choice of
antibiotic may depend on such factors as the stage of the
disease and whether your joints are inflamed.
If you are in stages 2 or 3 of the disease, you may also
need other treatments. This is especially true if you have
infection or inflammation of the heart, central nervous
system, or joints.
Pregnant and nursing women:
If you are pregnant and have Lyme disease, you may pass the
disease to your baby. Although this happens rarely, you
should call your healthcare provider right away 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 of infection, contact your provider for advice.
How long will the effects last?
While you have the disease the symptoms may occur in cycles
lasting a week or so.
In most cases the symptoms go away a few weeks or months
after antibiotic treatment, but sometimes the symptoms last
several years. For example, after treatment for stage 1 of
the disease, you may have minor recurrences of headaches,
muscle or joint pain, or fatigue, but eventually you should
recover completely.
If the disease is not diagnosed and treated, the symptoms
can last for several years, but they will gradually lessen.
Permanent problems caused by the disease depend on your
situation. Meningitis, which can strike in stage 2, can be
life threatening, but this is rare.
How can I take care of myself?
To help take care of yourself, follow the full course of
treatment prescribed by your healthcare provider. You need
to take all of your antibiotic therapy. Do not stop taking
antibiotics because you start to feel better or your
symptoms go away. If you have side effects from the
antibiotic, call your provider about possibly getting a
different prescription.
What can be done to help prevent Lyme disease?
To avoid getting Lyme disease, follow these measures:
- Be aware of the areas where ticks live. Do not walk,
camp, or hunt in the woods of tick-infested areas without
precautions.
- In areas of thick underbrush, try to stay near the center
of trails.
- When you are outdoors, wear long-sleeved shirts tucked
into your pants. Wear your pants tucked into your socks
or boot tops if possible. A hat may help, too. Wearing
light-colored clothing may make it easier to spot the
small tick before it reaches your skin and bites.
- Use approved tick repellents on exposed skin and
clothing. Do not use more than recommended in the
repellent directions. Do not put repellent on open
wounds or rashes. Wash the spray off your hands. Be
careful with children because the repellents can make
them ill.
DEET is a very effective repellent, but adults should use
products with no more than 35% DEET. Children should use
repellents with no more than 10% DEET. DEET should be
washed off your body when you go back indoors.
Picaridin is another repellent recently made available in
the US. It can be less irritating to the skin than DEET.
Some products containing permethrin are recommended for
use on clothing, shoes, bed nets, and camping gear. Do
not put permethrin on your skin.
- Treat household pets for ticks and fleas. Check pets
after they've been outdoors.
- Brush off clothing and pets before entering the house.
- After you have been outdoors, undress and check your body
for ticks. They usually crawl around for several hours
before biting. Check your clothes, too. Wash them right
away to remove any ticks.
- Shower and shampoo after your outing.
- Inspect any gear you have carried outdoors.
- Remove an attached tick with tweezers by grasping the
tick as close to your skin as possible and gently pulling
it straight away from you until it releases its hold.
Don't twist the tick as you pull, and don't squeeze its
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 include a
pair of tick tweezers in your first-aid kit. The
tweezers are available at many sporting goods stores.
- If you do get bitten, see your healthcare provider.
Save the tick in case you later start having symptoms of
disease and need to know what kind of tick bit you. Put
the tick in a clean dry jar, small plastic bag, or other
sealed container and keep it in the freezer.
Identification of the tick may help your provider
diagnose and treat your symptoms. If you do not have any
symptoms of disease after 1 month, you can discard the
tick.
- If you had a shot against Lyme disease (shots were
available until 2002) you are probably no longer
protected because the vaccine loses its effect over time.
This content is reviewed periodically and is subject to
change as new health information becomes available. The
information is intended to inform and educate and is not a
replacement for medical evaluation, advice, diagnosis or
treatment by a healthcare professional.
Copyright © 2007 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.