Chiggers are active from spring to late fall. Nymphs and adults feed on insect eggs, small insects and other organisms found on or near decaying wood. Larval chiggers congregate in shaded niches near the tips of grass leaves, weeds, sticks and other objects close to the ground. They are activated upon the approach of people, probably by odor, carbon dioxide output and other stimulating factors, and crawl onto people for feeding. Their preferred feeding locations on people are parts of the body where clothing fits tightly over the skin such as around the belt line, waistline, undergarments and under socks, or where the flesh is thin, tender or wrinkled such as the ankles, in the armpits, back of the knees, in front of the elbow, or in the groin region

Chigger larvae do not burrow into the skin, nor do they suck blood. The reason the bite itches so intensely and for such a long time is because the chigger injects saliva into its victim after attacking the skin. This saliva contains a powerful digestive enzyme that literally dissolves the skin cells it contacts. Also, this digestive fluid causes surrounding tissues to harden, forming a straw-like feeding tube of hardened skin cells from which further, partially-digested skin cells may be sucked out.

When someone itches the bite they almost always dislodge the chigger from the first scratch, however, the chigger is probably already gone from showering considering we don't feel the effects of the bite till many hours later. That is why they say the chigger is gone by the time it begins to itch.

It is the larval stage that is parasitic. Their primary hosts are reptiles and birds, with mammals (including people) secondary, almost accidental hosts. They seek tender skin, attach to the surface, inject a saliva containing a digestive enzyme and drink the dissolved skin tissue. Your body responds to this with an itchy allergic reaction. Adult chiggers are not parasitic and feed on various plant materials and other small arthropods.

Chigger larvae do not burrow into the skin, nor do they suck blood. The reason the bite itches so intensely and for such a long time is because the chigger injects saliva into its victim after attacking the skin. This saliva contains a powerful digestive enzyme that literally dissolves the skin cells it contacts. Also, this digestive fluid causes surrounding tissues to harden, forming a straw-like feeding tube of hardened skin cells from which further, partially-digested skin cells may be sucked out.

The itching probably results from the digestive action of the enzymes injected by the larva into the skin. Affected skin tissue becomes red and swollen. It may completely envelop the feeding chigger, making the chigger appear to be burrowing into the skin. Chigger bites have a more severe effect on some persons than others. The bite itches intensely and may continue itching for several days after the chigger is killed or drops off. Any welts, swelling, itching, or fever will usually develop three to six hours after exposure and may continue a week or longer. If nothing is done to relieve itching, symptoms may continue a week or more. Scratching a bite may break the skin, resulting in secondary infections. Chiggers are not known to transmit any disease in the United States.