Chiggers, often known as red bugs or harvest mites, are not insects but rather the tiny, parasitic larval stage of mites belonging to the Trombiculidae family. These microscopic arachnids are notorious for causing intense itching after attaching to a host. While they are most prevalent in the southeastern and central United States, chiggers have a wide global distribution and can thrive in any temperate climate that offers suitable habitat. The question of their presence in California often arises because the state’s climate is less uniformly humid than the Deep South, but chiggers are confirmed to be established in specific Californian environments.
Confirming Chigger Presence in California
Chiggers are present in California, though their distribution is often more localized than in other parts of the country. The species most commonly associated with human infestation in the state is Eutrombicula batatas, which has been documented in the lower San Joaquin Valley. Reports of typical chigger attacks have been confirmed, particularly in areas like Bakersfield, where local mosquito abatement districts have long been aware of complaints.
Chiggers thrive in areas that provide warmth, moisture, and dense vegetation. In California, this includes the grassy, weedy upland areas and along the edges of wooded habitats found in the Central Valley and foothills. They are most active when ground temperatures range between 77°F and 86°F, becoming inactive when temperatures drop below 60°F.
Recognizing Chiggers and Bite Symptoms
The chigger that causes irritation is the six-legged larva, a creature so small it is nearly invisible to the naked eye. These larvae are typically yellowish to light-red and will crawl onto a host from vegetation. They do not burrow into the skin or feed on blood.
When a chigger attaches to the skin, it injects digestive enzymes that break down skin cells. The body’s inflammatory reaction forms a hardened tube, called a stylostome, through which the mite feeds on the liquefied tissue. This feeding process usually lasts for a few days, but the intense itching often begins hours after the initial exposure. The resulting bite appears as red bumps or welts, sometimes resembling pimples or small hives, known medically as trombiculiasis. These lesions are commonly found in clusters where clothing is tight, such as around the ankles, waistline, and in skin folds.
Prevention and Immediate Relief Strategies
Preventing chigger bites centers on limiting exposure in infested habitats and creating barriers against the mites. When entering tall grass, brush, or wooded areas, wearing protective clothing is effective. This includes long sleeves and long pants, with pant legs tucked into socks or boots to prevent mites from gaining access to the skin.
Insect repellents containing DEET should be applied to exposed skin. For clothing, using products containing permethrin is effective, as this insecticide kills the mites on contact. Permethrin should be applied to clothing, not skin, and allowed to dry completely before wearing. After suspected exposure, shower immediately with soap and water, lathering and rinsing several times to wash off any unattached mites.
Immediate Relief
If a bite occurs, managing the itching and inflammation is key. Applying over-the-counter anti-itch creams, such as topical corticosteroids or hydrocortisone, can reduce discomfort. Oral antihistamines can also be taken to control the allergic reaction and itching, especially if sleep is affected. Avoid scratching the bites, as this can break the skin and introduce bacteria, potentially leading to a secondary infection.