What should I know about ticks and Lyme disease?

Globe and Mail

2 days ago

Ask a Doctor is new series of physician-authored columns offering insights and advice on common health topics. It is not a substitute for seeking medical care.
Spending time outdoors after our long winter is one of the best parts of warmer days in Canada. But spring is also when we start to see a rise in tick bites and Lyme disease.
Cases have increased dramatically in recent years. In 2024, a record 5,239 cases of Lyme disease were reported across the country, according to the Public Health Agency of Canada – up from 522 cases in 2014.
Whether you're camping, gardening, hiking or out with your dog, it's important to know how to protect yourself from tick bites – and what to do if you find one. Here are six key things I want you to know.
What causes Lyme disease?
Lyme disease can occur when a human is bitten by an infected blacklegged tick (also called a deer tick) or western blacklegged tick. Ticks can typically be found in brushy, grassy or wooded areas, but in recent years they've appeared in urban settings as well. (I recently had a patient come in with three ticks after walking through a city ravine.) Ticks can be active any time the weather is above 4 degrees, not just in the summer months. Young ticks can be as small as a poppy seed and easy to miss.
The good news? To spread Lyme disease a tick usually needs to be attached for at least 24 hours – so early detection can make a big difference.
What are the early signs of Lyme disease?
Lyme disease can be difficult to diagnose as it causes myriad symptoms and not everyone gets the same ones. The classic early sign is a round rash, known as a bull's-eye rash because of its characteristic appearance. But it doesn't always happen, and it can look different on darker skin. Flu-like symptoms such as chills, body aches, fever and fatigue can develop anywhere from three to 30 days after the bite.
If the infection is untreated, it can cause more severe symptoms weeks or months later, including facial paralysis, joint pain, nerve pain or abnormal heartbeat.
What should I do if I'm bitten by a tick?
Stay calm and try to remove the tick carefully. Grasp the tick as close to the skin as possible using fine-tip tweezers and pull it straight out (or get help from a health care provider). Clean the area with soap and water or an alcohol-based sanitizer.
Consider uploading a photo of the tick to eTick.ca, a free Canadian tool that helps identify tick species to assess your risk.
If the tick was attached for more than 24 hours, or you're unsure of the timing of the bite, contact your health care provider as you may be eligible for a preventive dose of antibiotics to stop an infection before it starts.
What if I suspect I've been bitten, but I'm not sure?
Ticks are tiny, and their bites are often painless. If you've spent time outdoors, especially in areas where blacklegged ticks are common, and you start feeling unwell (flu-like symptoms, fatigue or that telltale rash), it's worth checking in with your health care provider.
Early Lyme disease is diagnosed based on your symptoms and exposure history, not just a blood test. In the first few weeks after a bite, testing may not show anything, since the body hasn't had time to produce enough antibodies. That's why your doctor may still recommend treatment even if the test is negative.
Why is Lyme disease important to treat and prevent?
While most people who get Lyme disease and start treatment early will recover fully, some people may experience persistent symptoms. This can include difficulty concentrating, joint pain and fatigue that can severely impair function and daily activities. It is not clear why this happens, but it is very real for the people who experience it. These patients should not be dismissed as they deserve care, support and follow-ups.
How can I prevent tick bites?
The best defence against Lyme disease is prevention. Start by sharing this article with loved ones and follow the next steps to ensure you stay safe when outdoors:
As we head into warmer weather, I'm looking forward to enjoying the outdoors alongside you, but let's do so safely. Being aware of Lyme disease and how to prevent it is key to protecting yourself and your loved ones.
Dr. Sheila Wijayasinghe is a menopause-certified family physician practising at St. Michael's Hospital in Toronto, and the medical director of primary care outreach at Women's College Hospital. She is also the resident health expert on CTV's The Social, and co-host of The Doc Talk Podcast.