Nobody likes chiggers, those awful things that bite in places you can’t scratch in public. But what are they really, how do you treat the bites, and how do you keep from getting bites?
What are chiggers?
Chiggers are a kind of mite, an insect-like arachnid with eight legs. They have an incomplete metamorphosis which means they go from egg to larva to nymph to adult without a pupal stage. The six-legged larva is microscopic and adults are bright red and are often called red bugs. It is the six-legged larval stage that causes all the trouble and are what we call chiggers.
These mites are common in many parts of the world, and have different names in different places. All of them are the larval stage of a related family of mites. In the United States, these critters aren’t found in the north, at high altitudes or in very dry environments, but they are common in the Austin area. Chiggers particularly like wet areas along streams, but can be found in lots of other places. They attach themselves to tall grass, and when a human brushes against the grass, they latch on and move upwards along the body. Their favorite places to settle in for a meal are in places where clothing is tight, such as the tops of socks, clothing or underwear waistbands and bras. They will also settle into moist areas like the backs of knees, crotches and armpits.
What do they do?
These guys don’t actually burrow into your skin to feed, although this is a common misconception, Instead, they attach to your skin, bite, and inject enzymes to dissolve your skin and suck up the resulting skin soup. This forms a straw-tube, and if undisturbed, they can feed for several days. The bite may not be noticed for several hours, but then it causes intense itching, and usually by the time the itching starts, the larva has been knocked off.
What should you do if you have chigger bites?
There are many over-the-counter remedies that can help, mostly because they cut off air to the bite. A common remedy is nail polish, which can also help. You can also treat bites with an antihistamine cream or something like calamine lotion. Even so, the itching can last 2-3 weeks.
What about prevention?
The best way to prevent chigger bites is to avoid walking in tall grass, and therefore to keep your grass cut around your home. If you can't avoid long grass, use a deet based insect repellent and tuck your pants into your socks. Also, showering after coming indoors can dislodge the chiggers before they attach, and make any bites you do get feel better.
Don't be fooled into thinking these are mosquito bites! Mosquitoes are far too fragile to get into tight fitting clothing, so if you have bites in those areas, they are almost certainly chigger bites!
For more information, see this article by the Texas A&M Extension Service.