Chiggers are tiny pests associated with intense, irritating bites. A common misunderstanding surrounds their physical form and movement: they do not possess wings. These microscopic creatures belong to a different biological class than flying insects, which changes how they find and affect a host. Understanding what chiggers are is the first step toward effective prevention and treatment of their bothersome bites.
Why Chiggers Lack Wings: Classification and Locomotion
Chiggers (mites from the family Trombiculidae) are not insects but arachnids, making them close relatives of spiders and ticks. Because wings are exclusive to the class Insecta, chiggers structurally lack them. Like other arachnids, chiggers rely entirely on crawling for locomotion. This is a slow process for the larva, which measures only about 0.4 millimeters in length.
Chiggers find hosts by climbing onto low-lying vegetation, such as tall grass or brush, and waiting for a passing animal or human. This host-seeking method, called “questing,” involves positioning themselves on the tips of leaves or blades of grass. They grab onto clothing or skin upon contact, hitching a ride onto the host. Since movement depends on physical contact, bites are often concentrated in areas where a person walked through infested vegetation.
The Larval Stage: The Only Parasite
The chigger life cycle involves four stages: egg, larva, nymph, and adult. Only the larval stage, commonly referred to as a “chigger,” is parasitic and feeds on vertebrates. The larva has six legs, a characteristic that changes as it matures.
After feeding, the larva drops off the host to molt into the nymph stage, which matures into the adult mite. The nymph and adult stages are eight-legged and are not a threat to humans or animals. These later stages are free-living predators, feeding on small invertebrates and their eggs found in the soil and leaf litter. The intense irritation experienced by humans is caused only by the six-legged, nearly microscopic larva.
The Mechanism of the Chigger Itch
Chiggers do not burrow into the skin or feed on blood, correcting a common misconception. Instead, the larva uses specialized mouthparts to pierce the skin and inject a salivary secretion containing digestive enzymes. These enzymes break down and liquefy skin cells, which the chigger then ingests as food.
The host body reacts to this foreign substance by hardening the surrounding tissue, forming a straw-like feeding tube called a stylostome. The chigger feeds through this stylostome. The intense and prolonged itching is caused by the presence of this hardened tube, which is an allergic reaction to the digestive enzymes, not the mite itself. The chigger often detaches after a few days, but the stylostome and the resulting welt can persist and itch for up to two weeks.
Avoiding and Treating Chigger Infestations
Prevention relies on creating physical and chemical barriers against these crawling pests. Since chiggers climb onto low-lying vegetation, avoiding walking through tall grasses and thick brush is effective. Applying insect repellents containing DEET to exposed skin provides protection. A more effective strategy is treating clothing with permethrin-based products, which must be allowed to dry completely before wearing, as it creates an insecticide barrier toxic to the mites.
If exposure is suspected, taking a warm, soapy shower immediately after returning indoors is recommended to wash off unattached larvae. For existing bites, treatment focuses on relieving severe itching and inflammation. Over-the-counter topical anti-itch creams containing hydrocortisone or calamine lotion can soothe the irritated skin. Oral antihistamines help reduce the body’s allergic reaction, and applying a cold compress may provide temporary relief.