Chiggers are present in Oregon. These tiny mites, specifically their larval stage, are responsible for the intensely itchy bites many people experience after spending time outdoors.
Identifying Chiggers and Their Bites
Chiggers are the larval stage of mites belonging to the Trombiculidae family. These nearly microscopic creatures are typically reddish or orange and have six legs during their larval phase, which is the only stage that bites humans and animals. Adult chiggers, which have eight legs, do not bite humans; instead, they feed on small insects and their eggs. After hatching, chigger larvae position themselves on low-lying vegetation, waiting for a host to pass by.
In Oregon, chiggers can be found in various outdoor environments, particularly in areas with tall grasses, weeds, wooded regions, and damp locations such as those near lakes and streams. They are often concentrated in overgrown areas or places with significant brush. Chiggers thrive in warm temperatures, typically becoming active when ground temperatures are between 77 and 86 degrees Fahrenheit, and they cannot survive below 42 degrees Fahrenheit.
Chigger bites are initially painless, with intense itching developing several hours after attachment. The bites appear as itchy red bumps, resembling pimples, blisters, or small hives. These welts often have a bright red dot at the center and commonly appear in clusters. Bites are frequently found where clothing fits tightly, such as around the ankles, waistline, armpits, and behind the knees.
A common misconception is that chiggers burrow into the skin; however, they do not. Instead, they inject digestive enzymes that break down skin cells, which they then consume. The body’s reaction to these enzymes creates the itchy red welt. The itching can persist for several days, and the bumps may take one to two weeks to heal.
Preventing and Treating Chigger Bites
Preventing chigger bites involves taking precautions when in suspected chigger habitats. Wearing protective clothing is a primary defense; this includes long-sleeved shirts and long pants tucked into socks or boots to create a barrier. Treating clothing and gear with permethrin, an insecticide that kills chiggers on contact, offers an additional layer of protection. Permethrin should be applied to clothing in advance and allowed to dry, rather than directly to the skin. For exposed skin, insect repellents containing DEET, picaridin, or oil of lemon eucalyptus are effective at deterring chiggers.
Avoiding dense vegetation like tall grass, overgrown fields, and thick brush can significantly reduce exposure. When hiking, staying on established trails minimizes contact with chigger-prone areas. After spending time outdoors in potential chigger habitats, it is advisable to shower or bathe promptly with soap and water. This helps wash off any chiggers that may still be on the skin but have not yet attached or begun feeding. Additionally, washing all outdoor clothing in hot water and drying it on high heat can eliminate any remaining mites.
If chigger bites do occur, treatment focuses on alleviating the intense itching and preventing secondary infections. Begin by thoroughly washing the affected skin with soap and water to remove any lingering chiggers. Over-the-counter anti-itch creams such as hydrocortisone or calamine lotion can provide relief. Oral antihistamines may also help reduce itching, especially if it interferes with sleep. Applying cool compresses or ice packs to the bites can further soothe the skin.
It is important to resist scratching the bites, as this can break the skin and lead to bacterial infections, which may require medical attention. If symptoms worsen, signs of infection appear (such as increased warmth, redness, swelling, or pus), or the bites do not improve within two weeks, consulting a healthcare provider is recommended.