Chigger Mites (Trombiculidae)

Chigger mite identification

Chigger mites are the larval, six legged, stage of a mite 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. Chiggers do not burrow into skin like scabies mites but rather inject saliva into the wound which causes an allergic reaction and an intensely itchy area, followed by dermatitis.

Chigger mites are very small (0.2-0.4 mm ~ 1/100"), six-legged round mites with many setae ("hairs"). They can be red, yellow or orange in color. When seen, chiggers look like tiny red specks moving rapidly over the skin.

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 those 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.

Treating chigger bites

By the time the itching starts the chigger mites may be long gone. However, since chiggers may feed for hours, or even days, taking a warm shower once bites are noticed may disrupt further feeding by washing away any remaining mites. Severe allergic reactions should be seen by a medical professional. Less severe reactions can be treated with skin care ointments that are available over-the-counter.

Avoiding chigger bites

It is not practical to try to control either adults or larval stages of this mite with insecticide. In areas where chigger bites have occurred the best defense is to use repellents containing DEET or treat clothing with a permethrin-based spray.