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American dog tick

Dermacentor variabilis
Also called dog tick, wood tick

This common tick can spread Rocky Mountain spotted fever and tularemia, so remove it promptly and watch for fever or rash after a bite.

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.
American dog tick, photo 1
Photo: Owen Strickland, CC BY 4.0, via iNaturalist
SizeUnfed adult female about 5–6 mm (about 1/5 to 1/4 inch); male about 3.5 mm (about 1/8 inch). A fed female can swell to about 13–15 mm (about 1/2 inch or more). Larvae and nymphs are under 1 mm.
Where in the houseLiving room, bedroom, outside near the house
WhenAdults are most active from about April through August, with a peak in late spring and early summer.

Check these features

  1. Flat, oval, reddish-brown body with eight legs
  2. Whitish, cream or gray mottled markings on the shield behind the head (female) or across the whole back (male)
  3. Short mouthparts, much shorter than a blacklegged tick's
  4. Fed females swell into a gray, bean-shaped body up to about 1/2 inch long

Bites and stings

The bite is usually painless and the tick may stay attached for days if not found. The concern is disease, mainly Rocky Mountain spotted fever, which can become severe quickly without treatment. A tick left attached near the base of the skull can rarely cause tick paralysis (weakness or unsteadiness), which usually improves soon after the tick is removed. See a doctor promptly for fever, headache, rash or weakness in the days to weeks after a bite. Call 911 for trouble breathing, swelling of the face or throat, or severe symptoms.

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, including the scalp and back of the neck.
  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, headache, rash or unusual weakness over the next several weeks and see a doctor if any appear; mention the tick bite.
  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

Blacklegged (deer) tickThe deer tick is smaller and has a plain dark shield with no white or gray markings.
Lone star tickThe lone star female has one distinct white dot in the middle of her back instead of mottled markings.
Brown dog tickThe brown dog tick is plain reddish brown with no light markings and is often found indoors around dogs.
Rocky Mountain wood tickVery similar in look but lives in the Rocky Mountain states at higher elevations.

Why it came inside

American dog ticks live outdoors in grassy fields, brushy edges and wooded areas. They come inside on dogs, people and clothing; they are not known to set up indoor infestations.

Keep it out

  • Use an EPA-registered insect repellent and permethrin-treated clothing in grassy or brushy areas, following the product label.
  • Check dogs daily during tick season and ask your veterinarian about tick prevention products.
  • Do a full-body tick check after time outdoors and tumble-dry outdoor clothes on high heat for at least 10 minutes.
  • Keep grass mowed and clear brush, weeds and clutter near the house that attract the rodents young ticks feed on.

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.

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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. CDC
  5. CDC
  6. University of Maine Cooperative Extension

Checked October 18, 2026. Rating backed by 3 sources. How we rate danger.