Chiggers are the nearly microscopic larvae of certain mite species found in Michigan, posing a risk for intensely itchy bites during outdoor activities from spring through fall. Although often associated with the Southeastern U.S., the humid Midwest provides suitable environments for these pests to thrive. Understanding where these mites live and how they cause irritation is the first step toward effective prevention, especially for those who enjoy Michigan’s wooded and grassy recreational areas.
Chiggers Are Present in Michigan
The irritating bites are caused by the six-legged larval stage of the Trombiculidae family, not the adult mite. The species Eutrombicula alfreddugesi is common in North America and documented in Michigan. Chiggers do not burrow into the skin or suck blood. Instead, the larva attaches to a host and injects a digestive enzyme into the skin using specialized mouthparts. This enzyme breaks down skin cells, forming a hardened, straw-like feeding tube called a stylostome, which allows the chigger to ingest the liquefied tissue. The resulting severe itching and red welt are caused by the body’s inflammatory reaction to the injected enzymes and the stylostome’s formation. This reaction can begin within hours and the intense itching may persist for days after the mite has detached.
Typical Habitats and Peak Season
Chiggers thrive in environments with dense vegetation and moisture, making many areas in Michigan ideal habitats. They are often found in tall grasses, overgrown fields, and transition zones between woodlands and open areas. Specific locations include areas along lakes and streams, berry patches, and the edges of forest trails. Mites position themselves on low-lying vegetation, typically within 12 to 18 inches of the ground, waiting for a host. Chigger activity is primarily determined by temperature. Peak season runs from late spring through early autumn, typically May through September. They are most active when ground temperatures range between 77°F and 86°F. Activity significantly slows below 60°F and ceases entirely after a hard frost.
Avoiding and Treating Encounters
Prevention
Protecting yourself from chiggers requires a multi-step approach focused on creating barriers and repelling the mites. When entering high-risk areas, wearing long pants and long-sleeved shirts is advisable.
For maximum protection, several steps should be taken:
- Tucking pant legs into socks and the shirt into the waistband helps prevent the larvae from crawling directly onto the skin.
- Applying an insect repellent containing DEET to exposed skin offers effective protection against the mites.
- Treating boots, socks, and outer garments with an insecticide product containing permethrin kills the mites upon contact.
- After returning indoors from a potentially infested area, immediately take a warm shower and vigorously wash with soap and water to dislodge any unattached chigger larvae.
Treatment
If bites occur, the primary goal is managing intense itching and localized inflammation. Over-the-counter anti-itch products, such as calamine lotion or hydrocortisone cream, provide relief when applied directly. Oral antihistamines help reduce the body’s allergic response and diminish itchiness. Avoid excessive scratching, which can break the skin and lead to a secondary bacterial infection. Cool compresses can also soothe the irritated skin. The red welts typically resolve within one to two weeks as the body absorbs the stylostome and repairs the tissue damage.