A chigger is the larval stage of a mite in the family Trombiculidae, sometimes called harvest mites. These nearly invisible creatures are responsible for some of the most intensely itchy bites you can get outdoors in the United States. Only the larvae bite humans. The most common species in the eastern U.S. is Eutrombicula alfreddugesi, and nearly 250 chigger species have been documented across almost every state.
How Chiggers Actually Feed
One of the most persistent myths about chiggers is that they burrow into your skin. They don’t. They also don’t suck blood. What actually happens is stranger and, honestly, more impressive.
A chigger larva pierces the skin with its mouthparts and injects digestive enzymes, often at the base of a hair follicle. Those enzymes dissolve your skin cells into a liquid. Within a few hours, the tissue around the feeding site hardens into a tube called a stylostome. The chigger then drinks the liquefied skin cells through this tube, essentially using it like a straw. The chigger stays attached to the stylostome for hours or even days if left undisturbed, continuing to feed on dissolved tissue the entire time.
It’s the stylostome, not the chigger itself, that causes most of the itching and irritation. Your immune system reacts to the foreign tube of hardened tissue and the enzymes injected around it. This is why the itching continues long after the chigger has fallen off or been washed away.
Where They Live and When They’re Active
Chiggers thrive in brushy, grassy, or weedy areas that hold some moisture during the day. Think tall grass at the edge of a hiking trail, overgrown fields, berry patches, or the transition zone between a mowed lawn and woods. They tend to cluster in shady, humid spots rather than spreading evenly across a landscape. Sun-baked rocks and pavement are typically chigger-free because the mites avoid surfaces hotter than 99°F.
They’re most active on warm afternoons when the ground temperature sits between 77°F and 86°F. Activity drops off below 60°F, and the biting larvae are killed at temperatures below 42°F. This makes late spring through early fall the prime chigger season in most of the U.S., with peak activity in summer. They’re found across nearly every state, though they’re most commonly encountered in the Southeast, Midwest, and South Central regions where humidity and vegetation create ideal conditions.
What Chigger Bites Look and Feel Like
Chigger bites typically appear as a speckled line or cluster of small red spots or pimples on the skin. They don’t look like a single mosquito bite. Instead, you’ll often see a scattered grouping, sometimes dozens of bites in one area, because multiple larvae tend to climb onto you at once from the same patch of vegetation.
The bites concentrate where clothing fits snugly against your body. Waistbands, bra lines, sock lines, and the elastic edges of underwear are prime spots. Skin folds are also common targets. The most frequent bite locations include ankles, lower legs, behind the knees, the waist, and the groin. You likely won’t feel anything at the time of the bite. The itching builds over several hours, and it’s most intense during the first 24 to 48 hours. It can persist for a week or more as the stylostome slowly breaks down and your body clears the irritated tissue.
Treating the Itch
Since the chigger is usually long gone by the time you notice the bites, treatment focuses entirely on managing the itch and preventing infection. A hot shower with soap shortly after being outdoors can wash off any chiggers that haven’t yet attached. Scrubbing with a washcloth helps.
For bites that have already developed, over-the-counter anti-itch creams containing hydrocortisone or calamine lotion can reduce the urge to scratch. Oral antihistamines help some people sleep through the worst of the itching at night. Cool compresses applied to the bite clusters also provide temporary relief. The key is to avoid scratching as much as possible, because broken skin from scratching is the main way chigger bites lead to complications.
When Bites Get Infected
Chigger bites themselves aren’t dangerous in the U.S., but aggressive scratching can break the skin and introduce bacteria. Signs of a secondary infection include increasing redness that spreads beyond the original bite, warmth around the area, swelling, pain, and pus. In more serious cases, this can develop into cellulitis, a deeper skin infection that may cause fever, chills, and skin dimpling. If bite sites become increasingly painful or show signs of spreading redness days after the initial itch, that’s worth medical attention.
Preventing Bites Outdoors
The most effective chemical prevention is treating your clothing with permethrin at a 0.5% concentration. According to the CDC, permethrin-treated clothing repels and kills chiggers, ticks, mosquitoes, and other biting arthropods. You can buy pre-treated clothing or spray your own. The treatment lasts through multiple washes. For exposed skin, insect repellents containing DEET work well, with effectiveness peaking around a 50% concentration. Higher concentrations don’t add meaningful protection.
Beyond repellents, practical clothing choices make a real difference. Tucking pants into socks and wearing long sleeves in known chigger habitat blocks the larvae from reaching skin. Staying on cleared trails and avoiding sitting directly on grass or logs reduces exposure. After any time spent in brushy or grassy areas during warm months, showering within an hour or two and laundering your clothes in hot water removes chiggers before they can attach and feed.
Life Cycle Beyond the Bite
Only the larval stage of the chigger’s life cycle involves biting humans or animals. The larvae are tiny, roughly the size of a pinhead, and reddish-orange in color. After feeding for a few days, they drop off, molt into nymphs, and eventually become adults. Both nymphs and adults are free-living predators that feed on insect eggs and small invertebrates in the soil. They never bite humans again. A single chigger feeds on a host just once in its entire life, during that brief larval window. The rest of its existence is spent in the soil, entirely uninterested in you.