Chigger Bites: What They Look Like, How Long They Last and How to Get Rid of Chiggers

Chigger bites are small red bumps, often dozens at once, packed into the places where clothing was tight against the skin: the sock line, the waistband, the backs of the knees, the groin and the armpits. They show up a few hours to a day after you walked through tall grass, weeds or brush, itch harder than almost any other bite, peak on the second day and take one to two weeks to fade. The culprit is the larva of a mite so small you will never see it, and by the time the itch starts it has usually already fallen off. Nothing is living in your skin, nothing followed you into the house, and nothing needs to be dug out. What you are left with is a reaction to its saliva, and the job is to calm the itch, avoid infection and not get bitten again.

What chigger bites look like

• Size: 1 to 2 mm red dots at first, swelling to pea-sized welts of 5 to 10 mm in people who react strongly.
• Colour: bright red to pink, often with a tiny harder centre. Some bites develop a small clear blister or a pus-filled head after a day or two, and scratched bites crust over. On darker skin the bumps look purple, brown or simply raised, and the intense itch is the main clue.
• Grouping: clusters and bands of many bites, not neat lines and not single bites. Ten to fifty bites after one afternoon outdoors is ordinary.
• Location: anywhere clothing pressed against skin, or skin folds on skin. Ankles and the sock line, the backs of the knees, the waistband, the groin, under the bra line and in the armpits are classic. Bites on the face and neck are unusual for chiggers and point elsewhere (see the lookalikes below).
• Timing: nothing at the time. Itching starts roughly three to six hours after exposure, is at its worst 24 to 48 hours later and can go on for a week or more.
• The "chigger rash": when bites are dense enough they merge into a blotchy red rash around the ankles or waist that many people take for contact dermatitis or heat rash until it starts to itch.

In young boys, chigger bites around the groin can cause penile swelling, itching and painful urination a day or two after playing in grass. Paediatricians know it as summer penile syndrome. It is uncomfortable rather than dangerous, but it is worth a call to the doctor.

What chiggers are

Chiggers are not insects, and they are not the adult animal. They are the larval stage of trombiculid mites, relatives of ticks and spiders. In North America they are also called red bugs and harvest mites; in the UK and Europe the harvest mite or berry bug; in Australia scrub itch mites.

• Size: 0.2 to 0.3 mm, about the size of the full stop at the end of this sentence. A cluster of them on a blade of grass looks like a smudge of red dust. You can occasionally spot one on your skin as a moving red speck, but most people never see one.
• Colour and legs: red to orange, and six-legged as larvae. The nymphs and adults that follow have eight legs, are around 1 mm long, live in the soil, eat other small arthropods and their eggs, and never bite people.
• How they feed: a chigger does not burrow into the skin and does not drink blood. It attaches at a pore or hair follicle, injects saliva that dissolves skin cells, and sucks up the liquefied tissue. The skin around the feeding site hardens into a tiny straw-like tube called a stylostome. That tube, left behind after the chigger is gone, is what itches for so long.
• How long they stay: left alone, a larva feeds for three to four days. On people it rarely lasts that long; scratching, showering and clothing rubbing dislodge it within hours. That is why the folk remedy of painting bites with nail polish "to suffocate the chigger" does nothing. There is no chigger left to suffocate.

The common North American species is Eutrombicula alfreddugesi, found across the eastern, southern and central US and on into Mexico and South America. Europe's harvest mite is Neotrombicula autumnalis, which bites in late summer and autumn, hence the name. In Australia, Asia and the Pacific islands, some chiggers of the genus Leptotrombidium carry scrub typhus, a bacterial illness treated with antibiotics. North American and European chiggers are not known to transmit any disease; the itch, and the risk of a scratched bite getting infected, are the whole problem.

Chiggers are also not jiggers. The jigger or chigoe flea (Tunga penetrans) really does burrow into the skin of the feet, but it lives in tropical Africa, the Caribbean and South America and has nothing to do with the mites in a Missouri lawn.

Where and when you pick them up

Chigger larvae wait in clusters on the tips of grass blades, weeds and low leaves, and climb onto anything warm that brushes past: mice, birds, lizards, dogs, and you. Their favourite spots are damp, shaded and overgrown:

• tall grass and weedy field edges, especially where lawn meets woods
• berry patches, brambles and the brush along trails and creeks
• leaf litter and the base of shrubs
• orchards, overgrown gardens, roadside ditches and unmown parks
• golf course roughs, campsites and the grass around lakes and ponds

Once on you they walk, sometimes for an hour or more, until they hit a barrier (a sock cuff, a waistband) or a thin-skinned fold, and attach there. That walk is why the bites sit in bands where clothing was tight, and why a hot shower soon after you come indoors prevents most bites.

Chiggers need warmth. In the US they are active from spring through autumn whenever the ground is above about 16 °C (60 °F), peak in the heat of summer, and die off below about 6 °C (42 °F), so the first hard frosts end the season. In the warm south and in Mexico they can bite in any mild month. In the UK and northern Europe the harvest mite season runs from July to October. In Australia scrub itch is a problem in the warm, wet months.

One thing chiggers do not do is live indoors. They do not infest beds, sofas or carpets, and they are not passed from person to person. If new bites keep appearing every night in a house you have not left, you are not dealing with chiggers.

Chigger bites vs bed bug, flea, mosquito and scabies

The decisive questions are where on the body and where were you. Bites concentrated under elastic and in skin folds after an outdoor day are chiggers. Bites on the arms and face that appear overnight are more likely bed bugs; bed bug bites vs mosquito vs flea bites sorts those three, and bed bug pictures shows what to look for in the mattress seams. Itchy clusters on the ankles with a pet in the house are flea bites. A rash with burrows in the finger webs that is worse at night needs a doctor, because scabies is contagious and chigger bites are not. If none of these fit, the four-question method in What bit me? covers ticks, spiders and fire ants as well.

Three more lookalikes come up every summer:

• Poison ivy, oak and sumac cause streaks of blisters where the plant brushed the skin, often the forearms and shins, and no bumps under the sock line.
• Oak leaf itch mites, a Midwestern US problem in late summer and autumn, drop from oak trees and bite the face, neck, chest and arms, not the ankles and waist.
• No-see-ums and biting midges bite exposed skin outdoors, usually around dusk, and you feel the bite at the time.

If you can actually see and catch the thing that bit you, it is not a chigger. Photograph it and let Bug Identifier tell you whether it is a flea, a bed bug nymph, a tick or something harmless. If there is nothing to photograph and the bites fit the pattern above, you have your answer.

How long chigger bites last

Most chigger bites itch intensely for two to three days, then fade over one to two weeks as the body breaks down the stylostome. Bites that were scratched open last longer and can leave darker marks for weeks, especially on brown and black skin. Welts in people who react strongly can stay raised for ten days or more. New bites appearing a day or two after the first batch are not a sign that chiggers are still on you; they are bites you picked up at the same time that were slower to flare.

How to treat chigger bites

1. Shower as soon as you realise. Warm water and soap, with a flannel rubbed firmly over the ankles, waist and skin folds, removes any larvae that are still attached. The sooner the better: within an hour of coming indoors it prevents most bites.
2. Wash the clothes you wore in hot water and dry them on high heat, or at least bag them until you can. Chiggers can crawl off clothing onto the next person who handles it.
3. Calm the itch with an over-the-counter 1% hydrocortisone cream, calamine lotion, or an oral antihistamine, following the label. A cold compress for ten minutes helps at the worst of it. Check with a pharmacist first for young children, during pregnancy or if you take other medicines.
4. Do not scratch. Keep nails short and cover the bites on a child's legs if needed. Infection from scratching is the only common complication.
5. Skip the folklore. Nail polish, bleach, alcohol rubs and kerosene do not help and can damage the skin. The chigger is already gone.

When to see a doctor

• A bite becomes hotter, more painful or more swollen, oozes pus, or shows red streaks spreading from it. Those are signs of a skin infection, which may need antibiotics.
• A boy develops swelling of the penis, itching and painful urination after playing in grass (summer penile syndrome, usually treated with an antihistamine and a steroid cream).
• The itch is severe enough to stop you sleeping despite over-the-counter treatment. A doctor can prescribe a stronger steroid cream.
• You develop a fever, headache, body aches or a dark scab-like sore in the weeks after chigger bites in Australia, Asia or the Pacific islands. Scrub typhus is treated with antibiotics and gets worse the longer it is left.
• Call emergency services for swelling of the face, lips or throat, trouble breathing, or dizziness. That is an allergic reaction, not a bite problem.

How to get rid of chiggers

Off your body and clothes. A hot soapy shower and a hot wash of the clothes do the whole job. There is no infestation to treat indoors.

Out of the yard. Chiggers live in hot spots, not spread evenly over a lawn, so the aim is to make those spots unwelcoming:

• Mow regularly and keep the grass short, especially along fences, woods and ditches.
• Cut back brush, brambles and weeds, and rake up leaf litter.
• Open up shade so the ground dries out and warms. Chiggers avoid dry, sunny, bare areas.
• Discourage the wild hosts that keep chigger populations fed: keep rodents out of woodpiles and sheds, and do not leave pet food outside.
• For a persistent hot spot, a lawn insecticide labelled for chiggers or mites, applied only to that area in late spring and following the label, can help. Treating the whole yard is rarely necessary.

Before you go into chigger country.

• Wear long trousers tucked into socks, and a tucked-in shirt. The barriers chiggers stop at are the ones you choose.
• Use an insect repellent containing DEET or picaridin on skin and around the ankles, waist and cuffs, following the label.
• Treat boots, socks and trousers with permethrin, or buy permethrin-treated clothing. It keeps killing chiggers and ticks through several washes.
• Do not sit or lie directly on grass or logs in summer; use a blanket or a chair.
• Shower and change clothes within an hour of coming back. This single habit prevents most chigger bites.

Pets pick up chiggers too, usually on the ears, belly and between the toes, where the bites look like fine red grit. A bath removes them. Dogs and cats do not bring chiggers into the house in any numbers, and they do not pass them to you.

Frequently Asked Questions

What do chigger bites look like?

Clusters of small red bumps, 1 to 2 mm at first and sometimes swelling to pea-sized welts, concentrated where clothing was tight: the sock line, waistband, backs of the knees, groin and armpits. Some develop a tiny blister or pustule in the centre. They itch intensely, worst on the second day.

Do chiggers burrow into your skin?

No. A chigger attaches to the surface at a pore or hair follicle, dissolves skin cells with its saliva and feeds on the liquid. It is usually knocked off within hours. The red bump and the long itch come from the hardened feeding tube it leaves behind, not from a mite under the skin.

How long do chigger bites last?

The worst itching lasts two to three days and the bumps fade over one to two weeks. Scratched bites take longer and can leave dark marks for several weeks.

Can chiggers live in your bed?

No. Chiggers live in grass, weeds and leaf litter and need wild animal hosts and damp soil to complete their life cycle. They do not infest beds, furniture or carpets. Bites that keep appearing overnight at home are more likely bed bugs or fleas.

How do I tell chigger bites from bed bug bites?

By location and timing. Chigger bites sit in dense clusters under elastic and in skin folds and start a few hours after you were outdoors in grass or brush. Bed bug bites run in lines on skin left exposed above the covers, appear overnight, and come with black specks or shed skins in the mattress seams.

The short version

Dozens of fiercely itchy red bumps at the sock line and waistband, starting hours after tall grass and peaking the next day: chiggers. Shower, wash the clothes, treat the itch with hydrocortisone or an antihistamine, and leave the nail polish in the drawer. Mow, clear brush, tuck trousers into socks and use repellent to stop the next batch. If you find a bug you can actually see on your skin or clothes, it is not a chigger; photograph it and let Bug Identifier tell you what it is and whether it matters.