Summertime was made for chiggers. Laying in the grass, playing outdoors, and gardening puts us right in the path of chigger bites. But what ARE chiggers anyway? And are you correct in calling that itchy leg their fault?
Chiggers in Ohio are mites (Eutrombicula spp.) whose saliva causes intense, irritating itching in humans and animals. It is the mite's LARVAL life stage that is parasitic and feeds on humans. During the rest of its life, it is a beneficial predator of insect eggs and small arthropods like springtails. Chigger mites tend to be yellow-to-red in color though are usually too small to see. Chiggers are often mistaken as the red velvet mites, concrete mites, and clover mites that frequent our patios and lawn furniture. These are large mites, easily visible and thus quickly targeted as the source of our woes. Unfortunately it's never that easy! These larger red mites are NOT responsible for bites or itching in humans though they can stain clothing if sat on, and some may even be accidental invaders into homes. Click the links to learn more about those mites.
QUICK TIPS
- Chiggers do NOT burrow into skin. This is a myth!
- Chiggers do not suck blood. They actually feed on dissolved skin cells.
- Only the larval stage affects humans.
- Chiggers are very small (0.6 - 0.25mm) and are often unseen by the casual viewer.
- Showering will remove the mite;
- but itching reaction can last up to 2 weeks.
- Itch is the result of your skin's reaction to the mite saliva and can vary person to person; small red welts are common.
- CONTACT YOUR PHYSICIAN to discuss symptoms, reactions, and treatment options.
BIOLOGY
Mites have a unique lifecycle: Egg, Larva, Nymph, Adult.
The larva has only 6 legs. Only after a mite molts into its nymph stage does it possess all 8 legs characteristic of mites and the other arachnids. Mites can molt through several nymphal stages before reaching adulthood and sexual maturity. It can take weeks to months for the cycle to complete, depending on weather, temperature, and conditions. Females can produce several generations a year resulting in high numbers of mites in a given area and repeat trouble with chiggers throughout the season.
Chigger mites overwinter in the adult stage in soil. When temperatures increase, they emerge, mate and lay eggs in the soil in overgrown areas including uncut grass, fields, scrubby or weedy areas. Larval mites will climb to the end of grass blades or plants and wait to be picked up by the legs of animals and humans. When we walk by or play in the grass, the mites hitch a ride. They prefer to snuggle into spaces where tight clothing or elastic gives them shelter; therefore, the resulting itch may be focused around elastic around socks, ankles, waists, bra straps and armpits.
Chiggers will also feed on birds, mice and other rodents, cats and dogs, even reptiles, in addition to humans.
FEEDING
The baby mites excrete salivary enzymes into skin, often at the base of a hair follicle, in order to digest skin cells into a slurp-able shake. The dying skin cells form a stylostome, a tube-like channel from which the larva sucks the digested skin slurry. AKA your own skin forms a little straw that the mite uses to drink up.
Chiggers can feed for 2-4 days on their host, but on humans we usually knock them off long before they can complete a meal through movement and scratching. After feeding, larval mites drop off and molt into nymphs, moving onto different food items. The itching reaction and welts can take several hours to develop and will last well beyond the mite's presence.
You can shorten feeding time by quickly washing up after being in chigger territory. Because they have not burrowed in, thoroughly wiping down exposed skin with a wash cloth or a taking a good shower or bath will easily dislodge and remove the mites. Bathing also kills the chiggers. Make sure to wash clothing soon after as well to kill any remaining mites left on exposed clothing.
And lastly, stay away from folk remedies you may have heard. There is no need to apply anything other than soap and water to remove the mite. Then you only need to deal with the aftermath by addressing itch. Speak with your medical provider or a pharmacist for recommendations on dealing with the itch.
PREVENTION
They do not feed long and the itching is just the prolonged reaction to their spit... so PREVENTION is the best solution.
Using insect repellents and wearing protective clothing can reduce incidents of all manner of bug bites, including chiggers.
Chiggers prefer overgrown, grassy habitats. These transition zones along paths, fields, thickets and scrub could harbor chigger mites, in addition to our own yards. Long-term solutions could include brush control, frequent mowing, and landscape changes that increase light exposure and air flow (less humidity). These changes can make your yard less appealing to mites and ticks. You can survey your yard for chiggers as well by placing a black square of cardboard down in the lawn. After about 10 minutes, mites will start to crawl up onto the black surface and there you have a better chance of seeing those tiny specks. A magnifying lens will help you check for their presence. Look for yellowish-red dots darting about.
Insecticides are not generally recommended as rebound populations may occur and only the larval stage is a problem. However, hot-spot treatments are an option for quick knock-down in the short-term. Products containing bifenthrin or permethrin are common over the counter options, though these are also a risk to beneficial predators and pollinators in the landscape. To reduce non-target impacts, follow the label instructions carefully, do not apply where flowers are actively blooming, and avoid spraying at time when pollinators are actively flying. The label is the law for use and will also include important information about personal protective equipment needed, cautions for pets and children, and re-entry periods. Other products may be recommended through your lawncare professional.
Remember there are OTHER things in the wild that can give us the itchies, including poison ivy, mosquitos, and other skin allergies. Extension Staff are NOT MEDICAL PROFESSIONALS and cannot identify bites or diagnose clients with chiggers or other skin ailments. We cannot recommend treatments for skin conditions. Speak with your medical provider if you are having problems with itching or severe reaction to chigger saliva or other irritations.