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Removal · ID · risks
Prevention — for Canada

!   The 30-day watch   !

After removal.
What to watch for.

The tick is off. Most of the time, that’s the end of it. But Lyme bacteria and other tick-borne illnesses take days to weeks to show up, and the textbook signs you were warned about don’t actually appear in most Canadian cases. The honest version of the 30-day watch is on this page.

The big misconception

Most Lyme cases never have a bullseye.

The textbook erythema migrans rash — a clear central spot ringed by a red halo — is the cleanest possible sign of early Lyme infection. It’s also the exception, not the rule. Canadian and US case data consistently show that fewer than half of confirmed Lyme infections produce a recognisable bullseye. Many produce a solid red expanding patch, an oval blotch, or no rash at all.

Treat all of these as suspect

What counts as a Lyme rash.

  • A bullseye target (red ring around a clear or lighter centre).
  • A solid red, expanding patch larger than a loonie.
  • An oval or irregular red zone that grows over days, warm or not.
  • Any new rash that appears 3 to 30 days after a bite, even if it’s not at the bite site.

Photograph any of these with a ruler or coin for scale. Photos shown to a doctor are more useful than your memory of how big it was last Tuesday.

Also possible

A rash with no infection.

Not every red mark after a tick bite is Lyme. A small itchy red spot at the bite site, no bigger than a coin and not expanding, is almost certainly just a normal inflammatory reaction and resolves on its own in a week or two. The distinguishing feature is expansion: Lyme rashes grow over days; ordinary bite reactions don’t.

Week by week

What can show up when.

Different tick-borne illnesses surface on different schedules. A rough timeline:

Days 1–3

Almost certainly nothing

A small red itchy spot at the bite site is normal and not Lyme. Lyme bacteria take days to start producing symptoms — any symptom in the first 48 hours is far more likely a normal bite reaction or an unrelated bug.

Days 3–14

The window for an expanding rash

If a Lyme rash is going to appear, this is when it most often does. Anaplasmosis and ehrlichiosis can also start showing in this window — high fever, severe headache, deep muscle aches with no respiratory symptoms.

Days 7–28

Systemic and neurological signs

Lyme can begin to produce flu-like illness without a rash — unexplained fever, fatigue, joint and muscle aches, headache, swollen lymph nodes. Facial palsy on one side (sometimes called Bell's palsy) most often appears in this window too. So can heart-rhythm issues. Powassan virus (rare) can produce neurological symptoms here as well. Single-sided facial weakness is a doctor visit today, not tomorrow.

Weeks 4 and beyond

Late presentations

Untreated Lyme can produce arthritis (especially the knees), brain fog, persistent fatigue, or — less commonly — late facial palsy. Antibiotics still work at this stage but recovery takes longer. Any of these symptoms in someone who had a tick bite weeks earlier should still be flagged to a doctor.

Disease-by-disease symptoms and onset windows are on the risks page.

Where to go

Pharmacist, doctor, or ER.

The right destination scales with the symptom. In short:

When

Within 72 hours of a deer-tick bite, no symptoms yet.

Pharmacist

Ontario only (as of 2026): a pharmacist can prescribe a single 200 mg preventive dose of doxycycline. Walk in with the tick on its card and your timeline. Criteria on the removal page. In other provinces this pathway varies.

When

Any expanding rash, or systemic symptoms within 30 days of a bite.

Walk-in or family doctor

Fever, fatigue, joint or muscle pain, headache that won't quit, swollen lymph nodes, a rash anywhere on your body. Bring the tick if you saved it. Early antibiotic treatment for Lyme works very well; the earlier the better.

When

Severe or neurological symptoms within a month of a bite.

Emergency room (or 911)

Severe headache with neck stiffness, confusion, seizures, single-sided facial weakness, sudden vision changes, chest pain or heart palpitations, anaphylaxis. These can be signs of Powassan virus encephalitis, late-disseminated Lyme, alpha-gal reaction, or other serious disease. Don't wait it out.

What to bring

The conversation goes faster with three things.

  • The tick.Taped to its index card with the date and bite location written on it. If you didn’t save it, a clear photo is the next best thing.
  • The timeline. When was the bite. When was it removed. When did symptoms start. Even rough days are better than no dates.
  • Where you were.The province and ideally the area — a wooded part of Algonquin, a backyard in Lunenburg, a hike in Gatineau. Range matters: a tick from a known Lyme zone is treated differently than one from northern Manitoba where blacklegged ticks are still sporadic.

Related

More from the field guide.

Last reviewed

General information only — not medical advice. In an emergency, call 911. Read the full disclaimer.

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