Missouri is home to several tick species, and telling them apart matters because each one carries different diseases. The most common ticks you’ll encounter are the lone star tick, the American dog tick, and the blacklegged (deer) tick, with a few less common species also present in the state. Here’s how to identify each one based on size, color, and markings.
Lone Star Tick
The lone star tick is the most frequently encountered tick in Missouri, and the easiest to identify. Adult females are reddish-brown with a single, conspicuous spot in the center of their back. This spot is often iridescent and can range from bright white to cream, gold, or bronze. Unfed females measure 4 to 6 mm (roughly the size of a sesame seed to a small watermelon seed) and can swell to 16 mm or larger after a full blood meal.
Males are smaller, averaging 2 to 5 mm regardless of whether they’ve fed. Their coloring is dark brown, sometimes with reddish patches, and they have cream or whitish streaks along the back edges of their body. Males lack the single central spot that makes the female so recognizable.
Lone star ticks transmit ehrlichiosis, tularemia, and southern tick-associated rash illness (STARI). They’re also the primary cause of alpha-gal syndrome in the United States, a condition that triggers allergic reactions to red meat like beef, pork, and lamb. Symptoms of alpha-gal syndrome typically appear 2 to 6 hours after eating red meat and can range from hives and swelling to shortness of breath and dizziness.
American Dog Tick
The American dog tick is the species most responsible for transmitting Rocky Mountain spotted fever to humans. It’s brown to reddish-brown with distinctive gray or silver mottled markings on its back, sometimes called marbling. These markings are the quickest way to tell it apart from the lone star tick, which has either a single spot (female) or faint edge streaks (male) rather than broad, irregular patterning.
Unfed females are about 5 mm long, slightly larger than males at roughly 3.6 mm. A key structural difference: the female’s hard shield (the plate behind the mouthparts) covers only a small portion of her back, while the male’s shield covers nearly his entire upper body. After feeding, females can balloon to 15 mm long and 10 mm wide.
Nymphs are tiny, about 0.9 mm, and pale yellowish-brown before feeding, turning slate gray once engorged. Immature American dog ticks have red markings near their eyes but lack the white or silver patterning seen on adults. Besides Rocky Mountain spotted fever, this species also transmits tularemia and can cause tick paralysis.
Blacklegged (Deer) Tick
The blacklegged tick, commonly called the deer tick, is the primary carrier of Lyme disease in Missouri. It also transmits anaplasmosis. This tick is noticeably smaller than the lone star and American dog ticks, making it easier to miss on your skin or clothing.
The fastest way to identify an unfed female is by her two-tone appearance: an orange-red body surrounding a dark black shield behind the head. The legs are dark, almost black, which gives the species its common name. Males are uniformly dark brown to black. Neither sex has the white spots, silver marbling, or ornate markings found on the other two common Missouri species, making the blacklegged tick look comparatively plain.
Lyme disease symptoms typically appear within 3 to 30 days after a bite. The hallmark sign is a slowly expanding circular rash, sometimes clearing in the center to form a bull’s-eye pattern. The rash usually feels warm but isn’t painful or itchy. Fever, headache, extreme tiredness, and muscle aches can accompany it.
Less Common Missouri Ticks
The brown dog tick is found mainly in and around homes, kennels, and indoor spaces. It rarely bites humans but has been identified as a minor vector for Rocky Mountain spotted fever. It’s uniformly reddish-brown without any distinctive spots or silver markings, making it one of the plainer-looking ticks.
The Asian longhorned tick has expanded into Missouri in recent years. Unfed adults are light reddish-tan to dark reddish with brown markings, and lack the bold ornamentation of the lone star or American dog tick. After feeding, females turn grey-green with yellowish markings and swell to roughly the size of a pea. Males are rare in U.S. populations because females can reproduce without mating, essentially cloning themselves. Unfed nymphs and larvae are extremely small, about the size of a sesame seed or smaller.
Two soft-bodied tick species also live in Missouri. The relapsing fever tick transmits the bacteria that cause relapsing fever, and the bat tick has been found carrying certain pathogens but hasn’t been shown to pass them to humans. Soft ticks look very different from hard ticks: they lack the visible shield on the back and have a leathery, rounded appearance. Most people in Missouri will never encounter either species.
Quick Comparison at a Glance
- Single white/cream dot on center of back: Lone star tick (female)
- Silver or gray mottled marbling across the back: American dog tick
- Orange-red body with a solid black shield, dark legs: Blacklegged (deer) tick
- Plain reddish-brown, no markings: Brown dog tick
- Light reddish-tan with faint brown markings, very small: Asian longhorned tick
When Missouri Ticks Are Active
Ticks become active when temperatures reach about 45°F, which in Missouri can happen as early as February during mild winters. Peak activity runs from April through September, but warming trends have stretched the season in both directions. When winter temperatures rise above freezing, ticks can become active even in midwinter, and activity now extends well into late fall during mild years. Practically speaking, any time you’re outdoors in Missouri and the temperature is above freezing, a tick check afterward is worthwhile.
How to Remove a Tick Safely
Use fine-tipped, pointy tweezers. Clean the skin around the tick with rubbing alcohol (or soap and water). Grip the tick as close to your skin’s surface as possible, right at the head, then pull upward with slow, steady pressure. Don’t jerk or twist. Clean the bite area and your hands again afterward.
If part of the tick’s head breaks off, you can try to remove it with tweezers, but if you can’t get it, your skin will push it out naturally as it heals. Without tweezers, you can use a loop of thread or dental floss secured around the tick’s mouthparts and pull straight up. Avoid folk remedies like burning the tick with a match, smothering it in petroleum jelly, or painting it with nail polish. These methods don’t work reliably and can cause the tick to stay embedded longer.
What to Watch for After a Bite
After removing a tick, monitor the bite site and your overall health for at least 30 days. A circular rash expanding from the bite, especially one with a bull’s-eye pattern, is the classic early warning sign of Lyme disease and typically appears within 3 to 30 days. It usually feels warm but not painful. Fever, headache, muscle aches, joint stiffness, and extreme fatigue are other early symptoms across several tick-borne illnesses.
More serious symptoms can develop 3 to 10 weeks after a bite if an infection goes untreated. These include facial muscle weakness, neck stiffness, irregular heartbeats, and pain or numbness radiating to the hands or feet. Saving the tick in a sealed bag or photographing it can help with identification later if symptoms do appear.