-- Tiny, fiercely biting larval mites --
Summary: Chigger mites are tiny red mites that cause intensely itchy bites and dermatitis. These mites are most often encountered outdoors in brushy areas often while hiking or gardening. Insect repellents are somewhat effective against chigger mites but the best defense is to take steps to remove them from your skin if you believe you may have been in contact. Chigger mites do not burrow into skin or infest homes and are easily washed off the skin surface with soap and water.
Chigger mite identification
Chiggers are tiny, biting, six-legged (larval) mites in the family Trombiculidae. Later stages of this mite have eight legs and do not bite. Chigger larvae bite humans, other mammals, reptiles, amphibians, and birds. Unlike scabies mites, chiggers do not burrow into skin but rather inject saliva into the wound which causes an allergic reaction and an intensely itchy rash-like dermatitis (see chigger bite pictures).
Chigger mites are very small (0.2-0.4 mm ~ 1/100"), six-legged round mites with many setae ("hairs") covering the body and legs, see drawing (right). These mites can be red, yellow or orange in color. When seen on your body chiggers look like tiny red specks moving rapidly over the skin.
alternate names: harvest mite, red bug, redbug, jigger, scrub-itch mite
Chiggers are more common in tropical or semi-tropical climates but occur worldwide. Some species are responsible for the transmission of scrub typhus but not species in the US. Chigger mites can be encountered in any dense, brushy vegetation during any month in the southern US and late spring through early fall in the northern US. Chigger mites do not infest homes.
Symptoms of chigger mite bites
Bites initially blister then form red, intensely itchy areas that resemble bad mosquito bites or a rash, starting soon after some outdoor activity (see pictures here). The bites often cluster around areas of the body that were constricted by clothing. The intensity of the reaction varies by individual depending on their immune system, similar to other types of allergic reaction, and can change over time.
How to avoid chigger bites
It is not practical to try to control either adults or larval stages of chigger mites with insecticide. In areas where chigger bites have occurred the best defense is to use repellents containing DEET or to treat clothing with a permethrin-based spray (see Using Insect Repellents). Secondly, if an encounter with these mites is suspected take a shower to simply wash the mites off your skin.
Treating chigger bites
By the time the itching starts the actual mites may be long gone. However, since these mites may feed for hours, or even days, taking a warm shower when bites are first noticed will disrupt further feeding by washing away any remaining mites. Severe allergic reactions should be seen by a medical professional but less severe reactions can be treated with skin care ointments that are available over-the-counter. No other treatment is generally necessary.
Professional-level pest control supplies are generally not available in home and garden stores but can be found at DoMyOwn.com, our affiliate.
This DK Smithsonian Handbook is an excellent general guide to insect identification (available through Amazon, our Affiliate):
For additional resources see our Insect Identification article.
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