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Lone star tick

Amblyomma americanum

An aggressive biter that can spread ehrlichiosis and other infections, and its bites are linked to alpha-gal syndrome, a red-meat allergy that can be severe.

If you think you were bitten or stung, call Poison Help. Free, private, any hour.1-800-222-1222Call 911 for trouble breathing, swelling of the face or throat, or severe symptoms.
Lone star tick, photo 1
Photo: jdshide, CC0, via iNaturalist
SizeAdults about 3–4 mm (about 1/8 inch) unfed; nymphs about 1.5–2.5 mm (about 1/16 to 1/10 inch); larvae 0.5–1 mm. Fed females become much larger.
Where in the houseBedroom, bathroom, living room, outside near the house
WhenAdults are most active from about April through June and nymphs from May into August; larvae appear mid to late summer. In the far South they can be active in almost any month.

Check these features

  1. Rounded, reddish-brown to brown body with eight legs
  2. Adult female has a single bright white or silvery spot in the middle of her back
  3. Adult male has faint white streaks or spots around the rear edge of the body
  4. Long mouthparts, easy to see from above

Bites and stings

The bite itself is usually small. The main concerns are infections such as ehrlichiosis, which can cause fever, headache and body aches within days to weeks, and alpha-gal syndrome, in which a person later reacts to red meat or dairy, usually about 2 to 6 hours after eating, with hives, stomach pain, vomiting or swelling. See a doctor for fever, rash, or any allergic-type reaction after meals. Call 911 for trouble breathing, swelling of the lips, tongue or throat, fainting, or other severe reactions.

What to do

  1. If the tick is attached, remove it right away: grip it as close to the skin as you can with clean fine-tipped tweezers and pull up with steady, even pressure without twisting or squeezing the body. Do not use heat, petroleum jelly or nail polish.
  2. Clean the bite and your hands with soap and water or rubbing alcohol, and check yourself, children and pets for more ticks.
  3. Seal the tick in a bag or container (or put it in rubbing alcohol) and note the date of the bite.
  4. Watch for fever, rash, or hives or stomach upset a few hours after eating red meat, over the following weeks, and tell a doctor about the tick bite if any appear.
  5. For questions about a bite or symptoms, call Poison Help at 1-800-222-1222 (US, free, any hour). Call 911 for trouble breathing, swelling of the face or throat, or severe symptoms.

Look-alikes

American dog tickThe dog tick has mottled white or gray markings on the shield rather than one clear white dot, and shorter mouthparts.
Blacklegged (deer) tickThe deer tick is smaller and narrower, with a plain dark shield and no white markings.

Why it came inside

Lone star ticks live outdoors in woods with thick undergrowth and in leaf litter, especially where deer are common. They come indoors only by riding on people, pets or clothing.

Keep it out

  • Use an EPA-registered insect repellent and permethrin-treated clothing in woods and brushy areas, following the product label.
  • Do a full-body tick check after being outdoors, including your own yard, and shower within two hours of coming inside.
  • Tumble-dry outdoor clothes on high heat for at least 10 minutes.
  • Clear leaf litter, brush and tall grass near the house and keep play areas away from woods.
  • Ask your veterinarian about tick prevention for dogs.

What helps

Links go to Amazon search results so you can compare current options. As an Amazon Associate I earn from qualifying purchases. Always follow the product label.

Fine-tipped tweezers or tick remover

Grab the tick close to the skin and pull straight up with steady pressure.

See options on Amazon
EPA-registered insect repellent

Look for an EPA-registered repellent with DEET, picaridin, IR3535 or oil of lemon eucalyptus, and follow the label, especially for children.

See options on Amazon
Flea and tick prevention for pets

Ask your vet which product fits your pet. Never use a dog product on a cat.

See options on Amazon
Hand lens

A 10x magnifier makes small features easier to check, like eye patterns, markings or the shield on a tick.

See options on Amazon

Sources

  1. CDC
  2. CDC
  3. University of Florida IFAS Extension
  4. Pennsylvania Department of Environmental Protection
  5. CDC
  6. CDC

Checked October 18, 2026. Rating backed by 4 sources. How we rate danger.