Chiggers are tiny arachnids, related to spiders and ticks, that cause irritating bites. While typically not dangerous, their bites are a common nuisance and can lead to intense itching and discomfort.
Chigger Presence in Minnesota
Chiggers are found in Minnesota. These tiny mites, specifically the larval stage, thrive in outdoor environments like tall grasses, wooded regions, and moist soil, including areas around lakes and rivers.
Chiggers are most active from late spring through fall, with peak activity during summer when temperatures are warm and humid. They are active when ground temperatures range between 77°F and 86°F, becoming inactive below 60°F and dying below 42°F. In Minnesota, the North American chigger typically completes one generation per year, with its life cycle taking 50 to 70 days.
Recognizing Chigger Bites
Chigger bites manifest as small, red, intensely itchy welts on the skin. These bites often appear in clusters, particularly in areas where clothing fits tightly, such as around the ankles, waistline, armpits, or behind the knees. The itching typically begins several hours after exposure and can last for several days.
Chiggers do not burrow into the skin. Instead, the larval chigger pierces the skin and injects digestive enzymes that break down skin cells. This process creates a feeding tube, known as a stylostome, from which the chigger consumes the liquefied tissue. The itching and inflammation are a reaction to these enzymes and the stylostome.
Preventing and Treating Bites
To prevent chigger bites, wear protective clothing outdoors. This includes long-sleeved shirts and long pants, with pant legs tucked into socks or boots, to minimize exposed skin. Applying insect repellents containing DEET or picaridin to exposed skin can deter chiggers. Treating clothing with permethrin, an insecticide, provides additional protection, as chiggers are killed upon contact.
After spending time in chigger-prone areas, take a warm, soapy shower as soon as possible to remove unattached chiggers. Scrubbing the skin with a washcloth can dislodge these mites.
For treating bites, over-the-counter anti-itch creams like hydrocortisone or calamine lotion can alleviate symptoms. Oral antihistamines, like diphenhydramine, may also help reduce itching and inflammation. Avoid scratching to prevent secondary skin infections. If bites show signs of infection, such as increased redness, swelling, or pus, or if symptoms worsen, seek medical attention.