How long do insect bites last?
Most uncomplicated insect bites settle within three to seven days. Mosquito bites are usually gone in one to three; bed bug and chigger bites commonly itch for one to two weeks. A bite that is still getting worse after 72 hours is the one worth attention.
The normal curve
Almost every bite follows the same shape: the reaction builds for 24 to 48 hours, plateaus, then fades. The itch usually outlasts the visible mark by several days, which is why people think a bite is "not healing" when it is actually just still itchy.
| Bite | Usually gone in |
|---|---|
| Mosquito | 1–3 days |
| Flea | 3–5 days |
| Bed bug | 7–14 days |
| Chigger | 7–14 days of itch |
| Wasp or bee sting | pain hours, swelling 2–5 days |
| Horsefly | 3–7 days, slower if the cut is deep |
| Tick bite mark | 2–7 days after removal |
What makes a bite last longer
Scratching is the main reason. Broken skin heals slower than intact skin and invites bacteria, and a scratched bite can leave a dark or pale mark for months, particularly on deeper skin tones. Cold packs and an antihistamine in the first 48 hours do more for total healing time than anything applied later.
Sensitisation is the second reason. People react more strongly to insects they meet rarely, which is why holiday bites swell dramatically and local ones do not.
When the timeline itself is the warning
- Getting worse after 72 hours rather than better — think infection.
- Spreading redness with warmth and pain, especially with a red line tracking away from the site.
- A rash appearing 3 to 30 days after a tick bite, expanding outward. That timing is the classic Lyme pattern and does not look like an ordinary bite reaction.
- Fever at any point after a bite.
- A wound that darkens or breaks down over several days.
Any of these is a reason to be assessed rather than to keep waiting.
Marks that outlast the bite
Post-inflammatory pigmentation — a brown, grey or pale patch where the bite was — is not a scar and usually fades over weeks to months. Sun protection speeds that up. A genuinely raised, firm nodule that persists past a month should be looked at, particularly after a tick bite.
Common questions
Why do my bites itch more at night?
Body temperature rises slightly in the evening and there are fewer distractions, both of which amplify itch. Bed bug and scabies itch is also genuinely worse at night because that is when those species are active.
Is a bite that lasts two weeks normal?
For bed bugs, chiggers and no-see-ums, yes — prolonged itch is typical. For a mosquito bite it is unusual, and worth checking for signs of infection or scratching damage.
Does the bite mark mean the insect is still there?
No. In almost every case the insect has long gone. Chiggers, for example, drop off hours before the itch begins.
Get a photo assessment in the app
Everything above is free to read. The app adds what a page cannot: point your camera at the bite and get an assessment of the most likely cause, a severity read, and a day-by-day care plan — including the specific signs that mean you should be seen.
iPhone and iPad. Free to download.