Chiggers, also known as red bugs or harvest mites, are the larval stage of mites belonging to the family Trombiculidae. These microscopic arachnids are nearly invisible, measuring about 0.3 millimeters and having six legs. Chiggers cannot be passed from one person to another, nor can the resulting bites or rash be transmitted. They are acquired solely from outdoor environments, such as grassy or wooded areas, as interaction with a human host is an incidental part of their life cycle.
The Truth About Chigger Contagion
Chiggers cannot be transmitted between people due to their parasitic life stage and feeding method. Only the larval stage of the mite feeds on vertebrates, including humans, and they must transfer directly from vegetation or soil to a host. Once they drop off the host to continue their development, they are no longer a threat to humans, as the nymph and adult stages feed on small soil-dwelling arthropods.
Chiggers do not burrow into the skin or suck blood. Instead, the larva attaches to the skin, typically in areas where clothing is tight, and injects a digestive enzyme. This enzyme dissolves skin cells, creating a feeding tube called a stylostome, and the mite consumes the liquefied tissue. The intense itching and visible bumps are not the chigger itself, but a localized allergic reaction to the injected digestive enzymes.
The larval chigger typically feeds for a period of one to four days before dropping off naturally to molt. The severe itching often prompts scratching, which usually dislodges the mite well before it is fully fed. Because they do not survive long on a human host and cannot actively transfer to a second host, the mites and the resulting skin reaction are not contagious.
Identifying and Treating Chigger Bites
Chigger bites manifest as intensely itchy, red bumps that may resemble pimples, hives, or small blisters. The itchiness typically does not begin immediately, often starting three to six hours after the chigger first attaches to the skin. Symptoms are often most severe during the first 24 to 48 hours but can persist for up to two weeks.
The bites frequently appear in clusters or lines, especially in areas where clothing is tight against the skin, such as around the waistline, ankles, behind the knees, or in the armpits. The first step in treatment is to remove any remaining chiggers by washing the affected area with soap and water, ideally taking a hot shower and scrubbing the skin. Prompt action can help lessen the duration and intensity of the subsequent itching.
Treatment focuses on managing the allergic reaction and relieving the intense itching. Over-the-counter topical creams, such as hydrocortisone or calamine lotion, can be applied to soothe the skin. Oral antihistamines, like diphenhydramine, can also be taken to help reduce the body’s systemic reaction and alleviate itching, particularly if it disrupts sleep. Scratching should be avoided, as this can break the skin, leading to open wounds and potential secondary bacterial infections.
Preventing Future Chigger Exposure
Preventing contact with chiggers involves creating physical and chemical barriers when entering known habitats. Chiggers thrive in moist, overgrown areas like tall grass, brush thickets, and along woodland edges. Wearing protective clothing is an effective measure in these environments.
Long-sleeved shirts and long pants should be worn, with pant legs tucked into socks or boots to prevent chiggers from reaching the skin. Applying an EPA-registered insect repellent to both exposed skin and clothing provides protection. Repellents containing DEET are effective for skin application, while products containing permethrin can be applied to clothing and gear, but never directly to the skin.
Once outdoor activity is finished, taking a shower soon after returning home helps dislodge any mites that have not yet attached. Clothes and items that contacted the ground, such as blankets, should be washed in hot, soapy water. Keeping lawns mowed and shrubbery trimmed around the home reduces the favorable habitat for chiggers, minimizing yard encounters.