Scientists have found that tick-borne Lyme disease can be misdiagnosed because of its huge range of symptoms.
A new study, published in the Canadian Medical Association Journal, has suggested that this could even lead to death in some instances.
It highlights the case of a previously healthy 37-year-old man who died after the condition was dismissed as a viral flu-like infection.
Researchers said some of its rare signs include cardiovascular issues, atypical skin lesions and severe neurological symptoms.
Lyme disease is spread by ticks that have fed off infected animals, and in the UK it is most prevalent in grassy and wooded areas in southern England and the Highlands of Scotland.
Former England rugby captain Matt Dawson required heart surgery after contracting it, while singer Justin Bieber and model Bella Hadid have also been diagnosed.
When it affects the heart, the condition is known as Lyme carditis and can result in serious heart rhythm abnormalities.
The patient discussed in the study, known only known as Samuel, originally went to the doctor with flu-like symptoms, including a fever, sore throat and joint pain.
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Several weeks earlier, he had been in contact with ticks but did not recall removing one.
His doctor suspected a viral infection, and the patient's symptoms eased.
However, weeks later he was rushed to hospital with heart palpitations, shortness of breath and chest discomfort.
He was admitted to hospital and started on treatment for Lyme carditis, but his condition soon worsened and he died.
Dr Milena Semproni, infectious diseases fellow at the University of Manitoba, said: "The diagnosis of Lyme carditis is based on clinical suspicion and serology consistent with acute Lyme diseases.
"Unfortunately, diagnosis can be delayed while serology is being processed, and clinical suspicion should guide empiric treatment.
"Given that the early diagnosis is clinical, cases may be overlooked by clinicians, especially as Lyme disease moves into new geographic areas."
The study also looked at 10 other north American cases of sudden cardiac death attributed to Lyme carditis.
Eight of the patients were male, and the cases occurred between June and November, when ticks are active.
What are the symptoms of Lyme disease?
“The infection is often characterised by a circular red rash that usually forms the shape of a bullseye on a dartboard, which appears within one to four weeks of the bite,” she said.
However, not everyone who is infected with Lyme disease will develop a rash.
She added: “Sometimes, the only telling factors of Lyme disease are flu-like symptoms such as a high temperature, headaches, muscle and joint pain, and fatigue.”
According to LloydsPharmacy’s Matt Courtney Smith, because tick bites are not usually painful some people may be unaware that they have even been bitten.
He said: “But they can cause swelling, itchiness and bruising and appear as a small red lump on the skin.
“Ticks often remain attached to the skin and should be removed carefully with a pair of fine-tipped tweezers. Grip the tick as close to the skin as possible and pull steadily away from the skin.
“The area should then be washed with soap and water and an antiseptic cream applied to the skin around the bite to reduce itching.”
If the infection is untreated, it can progress into a more severe form of Lyme disease, where symptoms such as swollen joints, nerve issues, heart problems and difficulties with memory and concentration have been reported.
How is Lyme disease treated?
Dr Gall advised: “If you suspect that you might have Lyme disease, you should make an appointment with your doctor, who’ll send you for a diagnostic blood test.”
Thankfully, it is a treatable condition, with diagnosed patients being given a two- to four-week course of antibiotics to kill the bacteria.
“In rare cases, some people might still display symptoms for a long time after they’ve been treated, but a vast majority will recover quickly,” Dr Gall said.