The American chigger is a mite and is a member of the spider family along with other

parasitic insects like ticks. Chiggers are red because that is their body color,

not because they suck blood. Their mouth parts are too small to penetrate deeply into our skin.

Chiggers have a four stage life cycle. The stages are egg, larvae, nymph

and adult. It is mainly one species of chigger that is parasitic to mammalian vertebrates

including humans. The larval stage is what bites us. It attaches itself to a pore

or at the base of a hair and bites into the skin cell surface, breaking it. This allows

the larval chigger to gorge itself on the internal juices of the cell(s). Afterward it drops off

and molts from its 6 legged form into an 8 legged nymph.

Nymphs and adults eat decaying organic matter,

insect eggs and other small insects. It is the fluid the larval chigger injects into our skin

and the histamine release that occurs from its bite that causes the local allergic reaction.

Chigger bites itch intensely and cause redness and welts that range from small

red bumps to large fluid filled blisters.

The treatment is symptomatic to relieve inflammation and itching.

The pruritus or itching causes scratching that further damages the skin and sets up

the skin for a secondary bacterial infection. Chiggers in N. America do not transmit any diseases but those in

Asia can carry a bacteria of the rickettsia family that cause scrub typhus.

To avoid chiggers, avoid long shaded grass. Chiggers like shade and high humidity.

Keeping the grass cut short to allow penetration of the sun reduces the chigger population.

Do not sit or lie down in long grass or in the shade on grass or pine straw unless you want

to experience the unpleasant sensation of itching for several days.

Antihistamines, preferably longer acting varieties and topical corticosteroids are the

preferred and easily available medications to help the symptoms.

Using DEET on the skin of adults and permethrin on outdoor clothing will help

to reduce the bites by repelling chiggers some. There is no good way except light and dryness to

keep them out of your yard.

Chigger (CREDIT: Jerry F. Butler, University of Florida)

Reaction to chigger bites (CREDIT: Jerry F. Butler, University of Florida)