Chiggers: details

Chigger details in a nut shell.
1-chiggers don't burrow into human skin, they bite and attach to delicate skin with their mouth.
2-chiggers respond to temperature and are most active between 77-86 degrees.
3-wear correct clothes. tightly woven socks and clothes; tucked long pants, long sleeved shirts, and high shoes or boots.
4-scrub in hot soapy bath immediately after exposure.
5-change clothes when you get home and wash clothes before wearing again. put your shoes through a dryer cycle.

Avoid chigger-infested areas on warm afternoons
Chiggers are affected by temperature. They are most active in afternoons, and when the ground temperature is between 77 and 86 degrees. Chiggers become completely inactive when substrate temperatures fall below 60 degrees; temperature below 42 degrees will kill the chigger species that bite us.

If you can, plan your outdoor activities around your thermometer reading to keep chigger bites to a minimum. Researchers have also found that chiggers actively avoid objects hotter than 99 degrees. Rocks that have been baking in the sun are almost always free of chiggers, and make a safe place to sit when you are in a chigger-infested area.

Wear the right kind of clothes
The first line of defense against chiggers is the right kind of clothing. Shorts, sleeveless shirts and sandals are nearly suicidal in chigger infested areas. Wear tightly woven socks and clothes, long pants, long sleeved shirts, and high shoes or boots. Tucking pant legs inside boots and buttoning cuffs and collars as tightly as possible also helps keep the wandering chiggers on the outside of your clothes.

When you get home, change clothes as soon as possible, and wash them before you wear them again. If you don't, the chiggers will get you the next time you put them on.

Regular mosquitoes repellents will repel chiggers. All brands are equally effective. Applying these products to exposed skin and around the edge of openings in your clothes, such as cuffs, waistbands, shirt fronts and boot tops, will force chiggers to cross the treated line get inside your clothes.

Unfortunately repellents are only potent for two to three hours and must be reapplied frequently.

Take a hot, soapy bath immediately after exposure
The best precaution against chigger bites is simply taking a warm soapy bath with plenty of scrubbing as soon as possible after exposure. If you bathe at once, while the chiggers are still running over your body, you can wash them off before they bite. A bath will also remove any attached and feeding chiggers before you start to feel the itch.

http://mdc.mo.gov/discover-nature/avoid-outdoor-pests/chiggers -- source

Another MDC article about chiggers -- Got Chiggers? It Figures!