Permethrin is a tick-killing insecticide that works on clothes for about two weeks under normal conditions. Be sure to read label directions for use with children. Treat exposed skin with a good insect repellent. Lotion formulations work longer than spray-ons because they evaporate more slowly. Repellents containing DEET work best on ticks and are available in various concentrations up to 95 percent although 25-30 percent formulations are most common.
Most repellents work for two to three hours under normal conditions.
If you'll be out all day, refresh the repellent as needed, remembering that sweating can reduce its efficiency. If used with sunscreen, apply insect repellent 30 minutes to one hour after the sunscreen. After returning from an outdoor hike, check carefully for ticks on your skin. Generally, it takes several hours for a tick to select a site and bite deeply enough to transmit disease. If a tick is stuck, remove it by grasping its head with tweezers and pulling straight up.