Tick, Tick Bang!
Autumn is coming and this is the time to trek through the great British countryside but spare a thought for an increasingly common problem I encountered in the clinic just a few weeks ago. A patient hurriedly came into clinic apologising for being 5 minutes late. He mentioned he had forgot the time as he was out in his field and just remembered his appointment. Taking off his shoes I noticed something small drop onto the floor. On closer inspection I realised this was a tick. With the publication of the updated NICE guidelines on Lyme disease (LD) and 8000 new cases expected in the United Kingdom in 2019, I thought this would be an opportunity to look at a condition – more common than most realise.
A tick (Ixodes)
What is Lyme Disease?
Lyme disease is caused by a bacterial infection with the spirochete Borrelia Burgdorferi sensu lato genospecies. Named after the Connecticut town of Old Lyme where it was first reported in the 1970’s, the infection may result following an infected tick bite. Infection with the bacteria can lead to a wide spectrum of symptoms which can resemble other conditions making it difficult to recognise and consequently the condition maybe delayed in diagnosis, particularly in areas where ticks are not endemic. Symptoms suggestive of the condition include (1):
Fever and sweats
Neck pain or stiffness
Migratory joint or muscle aches and pain
Cognitive impairment, such as memory problems and difficulty concentrating
And less commonly:
Neurological symptoms, such as facial palsy, meningitis.
Where is Lyme Disease found?
Lyme disease is almost exclusive to the Northern Hemisphere (USA, Canada, Northern Europe and Northern Asia). In the United Kingdom, the tick responsible for carrying the infection (the vector) is most often found in grassy and wooded areas of the countryside particularly in the South of England and Scotland, although cases of LD following tick bites have been reported right across the UK including cases occurring in urban gardens and parks.
How common is it?
In the United Kingdom, data from laboratory confirmed cases of LD was 3986 cases in 2013-2016 (1.95 cases per 100 000 people). The figure has risen significantly since 2013 (1.62 cases per 100 000 people). As expected, most cases were confirmed in rural areas although only 4 postcode areas in the UK reported no cases during the study period. The areas with the highest incidence were Southampton (11.65 cases per 100 000 per year), Salisbury (10.75), Bournemouth (5.62), Reading (4.59), Dorchester (4.57), Guildford (4.31), Taunton (2.79), Torquay (2.75), Brighton (1.96) and Bath (1.84). The disease has a male preponderance and occurs most commonly in the 6-10 and 61-65 age groups (2). A second study using a Primary Care database, also identified a rapid rise in cases in recent years and suggested that in 2019 there could be as many as 8000 cases in the UK (3).
Celebrities who are said to suffered with the condition are numerous - George W Bush, Ben Stiller, Richard Gere, Neneh Cherry, Alec Baldwin, Michael J Fox, Matt Dawson, Debbie Gibson and Avril Lavigne to name a few (Source: Lyme Tales UK).
What happens when you get bitten?
Ticks, like spiders, are arachnids. The problem with ticks (Ixodes) is that they are very small and may carry the microbe responsible for Lyme disease in their gut. However, just because someone gets bitten by a tick does not mean that a person will automatically develop the disease. Only a small number of ticks are infected with bacteria responsible for Lyme disease. People (and animals) may acquire tick bites when walking through grassy areas. Ticks are most prevalent in the Spring to late Autumn. They are very small (around 2mm in size) and may climb onto the skin. It will tend to move a warmer area of skin (usually on the legs it will go for the trouser or sock line) where it can inflict a painless bite.
It will attach and begin draw blood to feed. At some stage, if the tick regurgitates, it may spill out the harmful spirochete into the skin. The infection maybe destroyed outright by the persons immune system or spread and become a multi-system infection. The time period from the initial bite to transfer of infection into the person’s skin is unknown. Some believe this to occur after the tick has been attached for 24 hours or more (4), although this a point of some debate, it is accepted that prompt removal of a feeding tick reduces the chance of acquiring infection (1).
Can early infection be recognised?
Bites from infected ticks can lead to the development of a well-recognised dermatological rash known as Erythema Migrans (EM) at the site of the bite. EM is a circular expanding area of erythema which usually develops within one or two weeks after the infected tick bite (but can take up to four weeks to become apparent). The rash may clear centrally as it evolves giving a “bullseye” appearance and typically is not hot to the touch or painful/itchy.
It is important to state however, that not all infected bites result in EM and so a number of patients may go onto to develop Lyme disease and its symptoms without any history of EM developing. In addition, a rash can develop as a reaction to a tick bite that usually develops and resolves within the first 48 hours of a bite. It is generally hot, itchy and painful is likely to be due to an inflammatory reaction to a common skin pathogen and not necessarily EM.
What if you suspect Lyme Disease?
Patients with a suspicion of Lyme disease should be referred to their GP. Diagnosis is usually made on the history, clinical features combined with a blood test known as an enzyme-linked immunosorbent assay (ELISA) test for Lyme disease. Treatment for most is with a course of oral antibiotics (typically amoxicillin, doxycycline or azithromycin). Children and other special groups may need specialist advice if infection is diagnosed.
Prevention of Lyme Disease
Prevention of LD can be facilitated by giving the patient advice about the condition and how it is acquired. If patients are likely to be in areas where ticks are known to inhabit, advice on long trousers and long sleeves, insect repellents and by making regular inspections after walking for ticks. If a tick is found it is important to give the correct advice for safe and effective tick removal. The aim is to remove the tick promptly, to remove all parts of the tick’s body and to prevent it releasing additional saliva or regurgitating its stomach contents into the wound. The most effective method is to use a tick removal tool (which can be bought online very cheaply) or pointed tip tweezers around the neck of the tick.
Tick Removal tool - It is hooked around the neck and is rotated to remove the tick in its entirety
The body of the tick should never be crushed as this can cause regurgitation. Techniques such as using ones fingernails, burning, nail varnish or petroleum jelly should be also avoided as this can lead to distress for the tick which can also increase the risk of regurgitation or release of infected material into the skin. Patient leaflets, posters and publications are available through the PHL website given below.
NICE Guidelines on Lyme Disease : https://www.nice.org.uk/guidance/ng95
Tick Bite Prevention and Lyme Disease Resources: https://bit.ly/1nXjONX
Lyme Disease Action UK : https://www.lymediseaseaction.org.uk/
1. National Institute for Health and Clinical Excellence. Lyme Disease. NICE Guideline [NG95]. London; 2018.
2. Tulloch JSP, Semper AE, Brooks TJG, Russell K, Halsby KD, Christley RM, et al. The demographics and geographic distribution of laboratory-confirmed Lyme disease cases in England and Wales (2013-2016): an ecological study. BMJ Open. 2019;9(8):e028064.
3. Cairns V, Wallenhorst C, Rietbrock S, Martinez C. Incidence of Lyme disease in the UK: a population-based cohort study. BMJ Open. 2019;9(8):e025916.
4. Piesman J, Maupin GO, Campos EG, Happ CM. Duration of adult female Ixodes dammini attachment and transmission of Borrelia burgdorferi, with description of a needle aspiration isolation method. J Infect Dis. 1991;163(4):895-7.