Lyme disease is a bacterial infection that is spread to humans by infected ticks. Ticks are tiny, spider-like insects 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. Lyme disease is caused by the Borrelia burgdorferi bacteria. The bacteria are present in the digestive systems of many different animals including mice, deer, pheasants and blackbirds. If a tick bites an animal that has the bacteria, the tick can also become infected with it. The tick can 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 that you have one attached to your skin. However, there is a higher risk that you will become infected if the tick remains attached to your skin for more than 36 hours. Once infected, the bacteria moves slowly through your skin and 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 symptoms of mid- and late-stage 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. 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 similar to those of other conditions. Blood tests are useful and important in acute infection but don't always confirm diagnosis.
The symptoms of Lyme disease usually fall into three distinct stages – early, mid and late. You should only experience symptoms of mid- and late-stage Lyme disease if you are not treated with antibiotics during the initial stage of the condition:
Early stage Lyme disease:
The symptoms of early stage Lyme disease develop three to 30 days after someone is bitten by an infected tick. The most common symptom of early stage Lyme disease is a distinctive circular skin rash, known as erythema migrans.
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 a period of several days or weeks. In up to a third of people with Lyme disease, the rash may be the only symptom.
Other symptoms of early stage Lyme disease are flu-like and can include:
- tiredness (fatigue)
- muscle pain
- joint pain
- fever or chills
- neck stiffness
Mid-stage Lyme disease:
The symptoms of mid-stage Lyme disease usually develop many weeks, or sometimes several months, after being bitten by an infected tick. However, they usually only affect people who were not treated with antibiotics at an early stage of the disease.
In untreated cases of Lyme disease, people will develop flu-like symptoms, such as aching muscles and tiredness. Some people may also experience two or three episodes of inflammatory arthritis (swelling and pain in the joints), which lasts for about a week. However, symptoms such as joint pain should eventually resolve by themselves, even if they are left untreated.
In around 15% of untreated cases of Lyme disease, people will get neurological symptoms (those that affect the nervous system). These symptoms include:
- numbness and pain in your limbs
- temporary paralysis of your facial muscles – usually only one half of the face is affected; this symptom is sometimes known as Bell’s palsy)
- impaired memory
- difficulty concentrating
- changes in personality
Some people may also develop meningitis, which is a serious condition where 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)
Seek immediate medical advice if you experience any of these symptoms.
Late-stage Lyme disease:
In a minority of untreated cases, the symptoms of late-stage Lyme disease can develop after many months, or even years. As with mid-stage Lyme disease, the symptoms can affect both the joints and the nervous system. The symptoms can include:
- long-lasting (chronic) joint pain and swelling
- pins and needles
- impaired memory
- difficulty concentrating
- blue or red rash, leading to thinning of the skin (atrophy), which is more common in older women
Diagnosed cases of Lyme disease can be treated with antibiotics. Your course of antibiotics will depend on the stage at which your Lyme disease is at, but you will usually need to take them for two to four weeks.
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.
The Health Protection Agency (HPA) estimates that there are 2,000 to 3,000 cases of Lyme disease in England and Wales each year, and that about 15%-20% of cases occur while people are abroad.
Parts of the UK that are known to have a high population of ticks include:
- the New Forest in Hampshire
- the South Downs
- parts of Wiltshire and Berkshire
- Thetford Forest in Norfolk
- the Lake District
- the Yorkshire Moors
- the Scottish Highlands
Most tick bites occur in late spring, early summer and during the autumn because these are the times of year when most people take part in outdoor activities, such as hiking and camping.
Preventing Lyme disease:
There is currently no vaccine to prevent Lyme disease. In 2002, a vaccine was introduced in America but it was later withdrawn due to 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 to 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.
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