A chigger is the parasitic six-legged larval stage of a mite in the family Trombiculidae, which are arachnids related to spiders and ticks. These nearly microscopic pests are responsible for intensely itchy bites that occur after outdoor exposure. Whether chiggers live in your hair or on your scalp is no; they are environmental pests that only temporarily attach to a host for a single meal. They do not burrow into the skin, nor do they establish a long-term colony or live on a host like lice or fleas.
Chigger Habitat and Host-Finding
Chigger mites thrive in outdoor environments that are warm, humid, and offer dense vegetation. Their preferred habitats include tall grasses, brush thickets, leaf litter, and areas along the edges of wooded or swampy land. The larvae, which are the only stage that feeds on mammals, are active from early spring through late fall when ground temperatures are generally between 77 and 86 degrees Fahrenheit.
The larvae wait for a host by climbing onto the tips of low-lying vegetation in a behavior called “questing.” When a person or animal brushes past, the chiggers quickly grab onto the shoes or clothing. These mites are extremely small, measuring only about 1/100th of an inch, making them nearly invisible. Once on a host, the chiggers crawl around, often for several hours, until they find a suitable feeding location.
Why Chiggers Avoid the Scalp
Chiggers do not suck blood or burrow beneath the skin, contrary to common belief. Instead, they pierce the skin with their small mouthparts and inject a digestive enzyme. This enzyme dissolves the surrounding skin cells, which the chigger then ingests as a liquefied tissue meal. The body’s immune reaction to the injected enzyme causes the surrounding tissue to harden, forming a tube called a stylostome, which the chigger uses like a straw.
Chiggers prefer areas where the skin is soft, thin, or wrinkled, and where clothing traps the mite in place. Bites typically cluster around areas of constriction, such as ankles, the waistline, or behind the knees. The scalp is generally unsuitable because it is often too exposed and dry, and dense hair makes it difficult for the mite to attach and feed undisturbed.
Although a chigger needs up to three days to complete its meal, they are often dislodged much sooner on humans. Scratching or the friction of movement is usually enough to remove the mite. If a chigger reached the scalp, washing the hair would quickly dislodge it, preventing successful feeding.
Immediate Actions for Exposure
If you suspect you have been in an area infested with chiggers, immediate action can prevent bites or reduce their severity. The first step upon returning indoors is to take a hot shower and vigorously scrub the skin with soap and a washcloth. This physical scrubbing action is effective in dislodging any larvae that may still be crawling on the body, though the intense itching usually begins only after the chigger has dropped off.
Clothing worn during the exposure should be removed and washed immediately in hot water to kill any remaining mites. For existing bites, which appear as itchy, red welts, treatment focuses on relieving the symptoms rather than removing the chigger, which is typically already gone. Over-the-counter anti-itch creams containing hydrocortisone or calamine lotion can soothe the skin and reduce inflammation.
Prevention is the most effective strategy when entering chigger habitats.
- Wear long pants and long-sleeved shirts, tucking pant legs into socks or boots.
- Apply insect repellents containing DEET to exposed skin.
- Use products with permethrin on clothing to create a chemical barrier.
- Keep lawns mowed and trim shrubbery to reduce the humid, dense cover chiggers require.