Chiggers are a type of mite that bite skin and feed on flesh as they grow in their larval stage. Once they reach full adulthood, they feed only off the ground. When a chigger bites your skin, it causes an allergic reaction and irritated itching for several days.
Chigger Bites
When a chigger bites a human, it attacks only thin areas of skin, such as you would find in your skin's wrinkles and creases. The chigger injects saliva into your skin as it bites.
Saliva Enzymes
The chigger's saliva contains an enzyme that breaks down your skin and liquefies it, according to the Missouri Department of Conservation. The chigger then feeds on your liquified skin, not your blood as with other biting insects.
Skin Reactions
Your skin reacts to the chigger bite by creating a tubelike structure around the path of the saliva. This tube is called a stylostome, and it works like a straw for the feeding chigger and also irritates the surrounding skin.
Itching
The appearance of a red welt happens when the stylostome irritates the skin around the chigger bite. The itching occurs because of your body's reaction to the saliva and stylostome.
