Lyme disease

Lyme disease is a bacterial infection spread to humans by infected ticks.

Introduction

Lyme disease is a bacterial infection spread to humans by infected ticks. Ticks are tiny arachnids found in woodland areas that feed on the blood of mammals, including humans.

Tick bites often go unnoticed and the tick can remain feeding for several days before dropping off. The longer the tick is in place, the higher the risk of it passing on the infection. Read more about the causes of Lyme disease.

Lyme disease can affect your skin, joints, heart and nervous system.

What are the symptoms of Lyme disease?

The earliest and most common symptom of Lyme disease is a pink or red circular rash that develops around the area of the bite, three to 30 days after someone is bitten. The rash is often described as looking like a bull’s-eye on a dart board.

You may also experience flu-like symptoms, such as tiredness, headaches and muscle or joint pain.

If Lyme disease is left untreated, further symptoms may develop months or even years later and can include:

  • muscle pain
  • joint pain and swelling of the joints
  • neurological symptoms, such as temporary paralysis of the facial muscles

Lyme disease in its late stages can trigger symptoms similar to those of fibromyalgia or chronic fatigue syndrome. This is known as chronic Lyme disease, although more research into this form of Lyme disease is needed.

A person with Lyme disease is not contagious because the infection can only be spread by ticks.

Read more about the symptoms of Lyme disease.

Unless in its early stages when a rash is present, diagnosing Lyme disease is often difficult as many of the symptoms are similiar to those of other conditions. If Lyme disease is suspected, blood tests may be able to confirm the diagnosis, but they often need to be carried out a few weeks after infection to reduce the risk of false-negative results.

Read more about diagnosing Lyme disease.

Diagnosed cases of Lyme disease can be treated with antibiotics. Your course of antibiotics will depend on the stage of your Lyme disease, but you will usually need to take them for two to four weeks.

Read more about treating Lyme disease.

How common is Lyme disease?

Lyme disease is the most common tick-borne infectious disease in Europe and North America. People who spend time in woodland or heath areas are more at risk of developing Lyme disease because these areas are where tick-carrying animals, such as deer and mice, live.

Most tick bites happen in late spring, early summer and autumn because these are the times of year when most people take part in outdoor activities, such as hiking and camping.

Read more about the causes of Lyme disease.

Preventing Lyme disease

There is currently no vaccine to prevent Lyme disease. In 2002, a vaccine was introduced in America but was later withdrawn because of concerns over side effects.

The best way of preventing Lyme disease is to avoid being bitten when you are in wooded or heath areas known to have a high tick population. The following precautions might help prevent Lyme disease:

  • Wear a long-sleeved shirt.
  • Tuck your trousers into your socks.
  • Use insect repellent.
  • Check yourself for ticks.
  • Check your children and pets for ticks.

If you do find a tick on your or your child's skin, remove it by gently gripping it as close to the skin as possible, preferably using fine-toothed tweezers, and pull steadily away from the skin.

Never use a lit cigarette end, a match head or essential oils to force the tick out.

Read more about preventing Lyme disease.

Symptoms

The most common symptom of early stage Lyme disease is a distinctive circular skin rash, known as erythema migrans.

Left untreated, Lyme disease may also lead to more serious symptoms developing weeks, or sometimes several months, after you have been bitten by an infected tick.

You should only experience later symptoms if you are not treated with antibiotics during the initial stage of the condition.

Early symptoms of Lyme disease

The symptoms of early stage Lyme disease may develop three to 30 days after being bitten by an infected tick.

The rash develops at the site of the tick bite and is often described as looking like a bull’s-eye on a dart board. The affected area of skin will be red and feel slightly raised to the touch.

The size of the rash can range from between 2cm-30cm (0.7-12 inches) and in most people it expands over several days or weeks. For many people with Lyme disease, the rash may be the only symptom.

Some people may also experience flu-like symptoms in the early stages, such as:

Later symptoms of Lyme disease

If untreated, some people may develop more serious symptoms. This can affect the joints, nerves, and in rare cases, the heart.

You should seek medical advice if you experience any of the symptoms below.

Joint pain

Some people may experience episodes of inflammatory arthritis (swelling and pain in the joints). However, symptoms such as joint pain should eventually resolve by themselves, even if they are left untreated.

Neurological symptoms

Neurological symptoms (those that affect the nervous system) can include:

  • numbness and pain in your limbs
  • temporary paralysis of your facial muscles - usually only one half of the face is affected (sometimes known as Bell’s palsy)
  • impaired memory
  • difficulty concentrating
  • changes in personality

In rare cases, some people may develop a type of bacterial meningitis, a serious condition in which the meninges (the protective membranes that surround the brain and spinal cord) become inflamed. The symptoms of meningitis include:

  • severe headache
  • stiff neck
  • increased sensitivity to light (photophobia)

Heart problems

In rare cases, untreated Lyme disease may lead to inflammation of the heart muscles (myocarditis).

Myocarditis can cause your heart to beat irregularly (palpitations), most often causing heart block.

Symptoms can include:

  • shortness of breath
  • fainting

Causes

Lyme disease is caused by the Borrelia burgdorferi bacteria. The bacteria are present in the blood of many different animals including mice, deer, pheasants and blackbirds.

If a tick (a tiny arachnid) bites an animal that has the bacteria, the tick can also become infected. The tick can then transfer the bacteria to a human by biting them and feeding on their blood.

Ticks are very small and their bites are not painful, so you may not realise you have one attached to your skin. However, there is a higher risk you will become infected if the tick remains attached to your skin for more than 24 hours.

Once infected, the bacteria moves slowly through your skin into your blood and lymphatic system. The lymphatic system helps fight infection and is made up of a series of vessels (channels) and glands (lymph nodes).

Left untreated, the bacteria that causes Lyme disease can damage the joints and the nervous system, leading to later symptoms of Lyme disease.

Where are ticks found?

Ticks can be found in any areas with deep or overgrown vegetation where they have access to animals to feed on.

Although this means they are most common in woodland and heath areas, they may also be found in gardens or parks where this kind of vegetation exists.

Groups at risk

The groups most at risk of getting Lyme disease include those who work in woodland and heath areas and those who take part in activities in these areas. For example:

  • hikers
  • campers
  • farmers
  • forestry workers
  • soldiers
  • gamekeepers

Most tick bites occur in late spring, early summer and autumn because these are the times of year when most people take part in outdoor activities, such as hiking and camping.

Read more about preventing Lyme disease.

Diagnosis

Lyme disease can be a difficult condition to diagnose, particularly in its latter stages. This is because its symptoms are also shared by more common conditions such as infections and arthritis.

The characteristic pink or red "bull’s-eye" rash of Lyme disease is important, and around 90% of people with the condition will develop the rash within 30 days of being bitten.

If you do not develop a rash, but develop later symptoms of Lyme disease, such as joint pain or flu-like symptoms, let your doctor know if you've spent time in woodland or heath areas where ticks are known to live.

If it's possible or likely you were bitten by a tick, your doctor should refer you for tests to confirm or rule out Lyme disease.

Testing

Tests for Lyme disease need to be carried out at least a few weeks after you were bitten by the tick because it can take this long for the infection to develop. You may need to be re-tested if Lyme disease is still suspected after a negative test result.

The tests used to help diagnose Lyme disease are:

  • enzyme-linked immunosorbent assay (ELISA) test
  • Western Blot test

These are described below.

ELISA test

The first test you will have is a type of blood test known as an enzyme-linked immunosorbent assay (ELISA) test. The ELISA test looks for specific antibodies produced by your immune system to kill the Borrelia burgdorferi bacteria.

The ELISA test is not 100% accurate as it can sometimes produce a positive result even when a person is not infected with Lyme disease (known as a false-positive result). This may happen if a different condition is causing your symptoms, such as syphilis, glandular fever or rheumatoid arthritis.

Because of this, a positive ELISA test is followed by a further test known as the Western Blot test.

Western Blot test

The Western Blot test involves taking a small blood sample. The proteins in the blood are separated and placed on a thin sheet of permeable material. The proteins can then be studied for antibodies used by the immune system to fight the bacteria Borrelia burgdorferi which causes Lyme disease.

If both the results of the ELISA test and the Western Blot test are positive, a confident diagnosis of Lyme disease can usually be made.

Treatment

Oral antibiotics (tablets, capsules and liquids) are recommended for treating Lyme disease. Most people will require a two- to four-week course depending on the stage of the condition.

If you are prescribed antibiotics, it is important you finish the course even if you are feeling better because this will ensure all the bacteria are destroyed.

If your symptoms are particularly severe and include arthritis or neurological conditions, antibiotic injections (intravenous antibiotics) may be used. Most people with later symptoms of Lyme disease will require a course of intravenous antibiotics.

Some of the antibiotics used to treat Lyme disease (both oral and intravenous) can make your skin more sensitive to sunlight (photosensitivity). You should check the leaflet that comes with your medication to see if this is the case.

Avoid prolonged exposure to the sun and do not use tanning equipment until after you have finished the course.

Pregnancy and breastfeeding

As a general rule antibiotics tend not to be prescribed during pregnancy as a precaution in case they affect the development of the baby.

However, if a positive diagnosis of Lyme disease is made then you may be prescribed antibiotics thought to be safe to use during pregnancy, such as azithromycin or clarithromycin.

If antibiotics cannot be prescribed then follow-up appointments will be made to check on your symptoms.

The Borrelia burgdorferi bacteria that cause Lyme disease cannot be passed on through breast milk, so it is safe to breastfeed if you have Lyme disease.

Prevention

There is currently no vaccine available to prevent Lyme disease. The best way to prevent getting Lyme disease is to be aware of the risks when you visit areas where ticks are likely to be found and to take sensible precautions.

When travelling to other European countries or to North America, you should also be aware of the risks.

You can reduce the risk of infection by:

  • being aware of ticks and the areas where they usually live
  • keeping to footpaths and avoiding long grass when out walking
  • wearing appropriate clothing in tick-infested areas (a long-sleeve shirt and trousers tucked into your socks)
  • wearing light-coloured fabrics that may help you spot a tick on your clothes
  • using insect repellents
  • inspecting your skin for ticks, particularly at the end of the day, including your head, neck and skin folds (armpits, groin, and waistband)
  • checking your children’s head and neck areas, including their scalp (skin on top of their head)
  • making sure that ticks are not brought home on your clothes
  • checking that pets do not bring ticks into your home in their fur

How to remove a tick

If you find a tick on your skin or your child’s skin, remove it by gently gripping it as close to the skin as possible, preferably using fine-toothed tweezers. Pull steadily away from the skin.

Do not use a lit cigarette end, a match head or volatile oils to force the tick out. Some veterinary surgeries and pet shops sell inexpensive tick removal devices which may be useful if you frequently spend time in areas where there are ticks.

Content supplied by NHS Choices