When do ticks bite? Blacklegged ticks (Ixodes scapularis or Ixodes pacificus), who carry the Borrelia burgdorferi bacteria that causes Lyme disease, can bite throughout the seasons. Immature ticks, also called nymphs, commonly bite during the spring and summer. Because of their small size, they are difficult to see on the body, and most people are infected with Lyme disease through the bite of an undetected immature tick. However, adult ticks, which commonly bite during the fall, also carry the Lyme disease bacteria. Though they are larger and easier to spot, they still pose a threat, so it’s important not to let your guard down.
Lyme disease is the most common tick-borne disease in the United States and Europe. Most cases in the United States arise from the mid-Atlantic, northeastern, and north-central parts of the country. Not every individual bitten by a tick will develop Lyme disease. Cases usually arise from parts of the country where the disease is more widespread. New England states, Wisconsin, and northern California are a few areas in which black-legged ticks are prevalent.
The early stages of Lyme disease can include a rash known as erythema migrans, which can occur on the thighs, trunk, armpits, or groin. The rash can begin as a small oval or round area and gradually expand within days. The classic Lyme disease erythema migrans rash looks like a bull’s eye target (see below). However, there are also various other rashes that can be seen with Lyme disease. Those with Lyme disease may also notice a headache, fever, fatigue, muscle and body aches. Some symptoms may not appear until several weeks or months later. These symptoms can include arthritis, especially in the knees, numbness, nerve pain, heart arrhythmias, facial nerve paralysis, and meningitis.
The initial bite of the Ixodes tick may go unrecognized due to the small size of the tick. The bite is typically painless. After a feeding period, the tick becomes engorged (with the human blood meal) and then the engorged tick typically falls off the skin in 2-4 days.
If you notice the tick on your skin, it is important to remove it as soon as possible. There are specific steps necessary to remove the tick safely:
- Use tweezers to grip the tick as close as possible to the skin
- Pull the tick upwards in a steady and even motion without twisting the tick. This could cause the mouthparts to break off from the tick and remain in the skin. If the mouthparts remain in the skin, attempt to remove them with tweezers. If you cannot, leave the mouthparts in the skin.
- After removing the tick, wash your hands and the bite area with soap and water or rubbing alcohol.
- Do not squeeze a tick with your fingers. A live tick can be disposed of by placing it in alcohol or flushing it down the toilet.
There are several ways you can prevent tick bites. Before spending time outdoors, put on Environmental Protection Agency (EPA)-registered insect repellants containing DEET, picaridin, IR3535, Oil of Lemon Eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. If wearing DEET, products with 20-50% DEET are most effective. Repellants that are not registered with the EPA have not been tested for safety or efficacy and are not recommended. Wear permethrin-treated clothes to prevent tick bites. Place clothes in the dryer for 10 minutes using high heat after returning from outdoors. Shower as soon as possible after engaging in outdoor activities; always remember to check for ticks in your hair, under your arms, behind your knees, and along the groin.
Lyme disease can be diagnosed through identification of the typical Lyme rash and with a blood test. It can be treated with antibiotics for 10-21 days. Most individuals respond well to treatment within 4 weeks. When Lyme disease is left untreated it can lead to several health issues such as joint, heart, or nervous system problems so early identification and treatment are critical. If symptoms persist, a medical provider may request a consultation with an infectious disease specialist to assist in management and treatment.
1 Centers for Disease Control and Prevention, “Lyme Disease: What You Need to Know.”
2 Susan S. Philip, “Spirochetal Infections” in Current Medical Diagnosis and Treatment 2018, (McGraw-Hill Education, 2018): 1514-1518.
4 “Lyme Disease: What You Need to Know.”
7 “Lyme Disease: What You Need to Know.”
10 Centers for Disease Control and Prevention, “Tick removal and testing.”
11 Centers for Disease Control and Prevention, “Preventing Tick Bites on People.”
12 John-Paul Mutebi and John E. Gimnig, “Mosquitoes, Ticks & Other Arthropods,” Centers for Disease Control and Prevention.
13 “Lyme Disease: What You Need to Know.”
14 Linden Hu, “Treatment of Lyme disease,” UptoDate, updated September 27, 2018.
16 Centers for Disease Control and Infection, “Understanding Tick Bites and Lyme Disease.”