Chiggers are the larval stage of mites belonging to the Trombiculidae family, known for causing intensely itchy welts on the skin. These microscopic pests, sometimes called red bugs or harvest mites, are barely visible to the naked eye. Only the six-legged larvae are parasitic; the eight-legged nymphs and adults are harmless predators feeding on small insects. Chiggers are typically encountered in outdoor areas like tall grass, wooded environments, and along lake and stream banks.
The Truth About Chigger Bites and Contagion
Chigger bites are not contagious and cannot be spread from one person to another. The intense irritation and rash that follow a bite are an allergic reaction to the digestive enzymes the mite leaves behind, not an active infection. The chigger itself is usually long gone by the time the symptoms of itching and red bumps become noticeable.
The larvae typically fall off or are accidentally rubbed or scratched off within a few hours to a couple of days after they begin feeding. The resulting inflamed area, which may look like a pimple or hive, is a localized reaction that does not contain the mite. Since the chigger cannot move from person to person, the bites pose no risk of contagion. Multiple people experiencing bites simultaneously simply means they were exposed to chiggers in the same infested outdoor area.
How Chiggers Attach and Cause Symptoms
The larval chigger does not burrow into the skin or suck blood. Instead, the tiny mite uses blade-like mouthparts to pierce the skin, often near hair follicles or pores. The chigger then injects saliva containing powerful digestive enzymes that liquefy skin cells.
The body’s immune response to this foreign enzyme causes the tissue around the feeding site to harden, forming a tube called a stylostome. The chigger uses this hardened structure like a straw to suck up the dissolved tissue for its meal. Chiggers prefer areas where clothing fits tightly, such as around the waistbands, sock lines, armpits, and behind the knees, because the constricted fabric helps keep them secured on the skin.
Immediate Relief and Managing the Itch
Immediate action after exposure can help reduce the severity of the reaction by removing any mites that may still be attached. Take a shower or bath quickly and wash the affected area thoroughly with soap and water. Scrubbing the skin gently with a washcloth can help dislodge any lingering chiggers, which will die once removed from the host.
To manage the itching, over-the-counter anti-itch treatments are recommended. Applying calamine lotion or hydrocortisone creams to the welts can help soothe the skin and reduce inflammation. Oral antihistamines, such as diphenhydramine, can also be taken to help control the allergic reaction. Avoiding scratching is important, as breaking the skin can lead to a secondary bacterial infection that may require medical attention.
Preventing Future Exposure
Proactive measures are the most effective way to avoid chigger bites when spending time in high-risk environments. Wearing protective clothing is highly effective, which includes long-sleeved shirts and long pants tucked into socks. Tightly woven fabrics offer a better physical barrier against the mites.
Applying insect repellents to both skin and clothing adds an extra layer of defense. Repellents containing DEET can be applied to exposed skin, while permethrin is recommended for treating clothing, but should not be applied directly to the skin. After returning indoors, wash clothes worn during outdoor activity in hot water to ensure any clinging chiggers are killed. Modifying the habitat by keeping lawns mowed and brush trimmed can also reduce the presence of chiggers near the home.