Chiggers are nearly invisible pests, close relatives of spiders and ticks, known for their intensely itchy bites. These tiny arachnids, also called harvest mites, red bugs, or scrub-itch mites, are the larval stage of certain mites in the Trombiculidae family. Despite their microscopic size, their presence is often felt through uncomfortable skin reactions.
The Chigger Life Cycle
Chiggers undergo a four-stage life cycle: egg, larva, nymph, and adult. Adult female mites spend winter in the soil, laying eggs in leaf litter and damp soil during early spring. These eggs hatch into six-legged larvae within five to seven days.
Only the larval stage is parasitic, feeding on humans and animals. Larvae climb onto vegetation, waiting for a host. Once a larva finds a host, it feeds for one to four days before dropping off to digest its meal and molt.
After feeding, the larva transforms into an eight-legged nymph, which is not parasitic and preys on small insects and their eggs. Nymphs then mature into eight-legged adults. The entire life cycle can range from 40 days to a year, depending on environmental conditions, with adult females producing multiple generations.
Where Chiggers Live
Chiggers thrive in environments with heat and humidity. They are commonly found outdoors in tall grasses, weeds, wooded areas, and berry patches. Moist soil near water, overgrown fields, and shaded locations are preferred habitats.
These mites are often encountered in low-lying vegetation, less than a foot off the ground. They are active from late spring through early fall, especially when ground temperatures are between 77°F and 86°F. Chigger activity decreases significantly as temperatures drop and they cannot survive below 42°F.
Understanding Chigger Bites
When chigger larvae encounter a host, they crawl until they find a feeding site, often where clothing fits tightly or skin is thin. They use sharp mouthparts to pierce the skin and inject a digestive enzyme. This enzyme breaks down skin cells, creating a hardened tube called a stylostome, through which the chigger extracts liquefied tissue.
Chiggers do not burrow into the skin or suck blood. The intense itching begins one to three hours after the mite injects its saliva and can last for days or weeks. Bites appear as small red spots, raised red bumps, or pustules, often clustered around the waist, ankles, or behind the knees. While chigger bites in the United States do not transmit diseases, certain species in other parts of the world can transmit scrub typhus.
Protection and Relief
Protecting yourself from chigger bites involves preventive measures when in infested areas. Wearing long-sleeved shirts and long pants, especially if tucked into boots or socks, creates a physical barrier. Applying insect repellents containing DEET or picaridin to exposed skin, and treating clothing with permethrin, deters chiggers. Avoiding tall grass, dense vegetation, and staying on marked trails reduces the likelihood of encountering these mites.
After outdoor activities, showering with soap and water as soon as possible helps dislodge any chiggers that have not yet attached or fed. Washing clothes in hot water eliminates lingering chiggers. For relief from existing bites, over-the-counter anti-itch creams like calamine lotion or hydrocortisone cream alleviate itching. Oral antihistamines and cool compresses also provide symptomatic relief.