Chigger bites are intensely itchy. A chigger is the tiny, six-legged larval stage of a mite in the Trombiculidae family, and it is the only stage that feeds on humans and animals. The discomfort begins hours after the mite has attached and is a direct result of the unique way the chigger feeds.
What Causes the Intense Itching
The extreme itch from a chigger bite is not caused by the mite burrowing under the skin. Instead, the larval chigger uses its small mouthparts to puncture the skin and inject a potent digestive enzyme into the tissue.
This enzyme breaks down skin cells, liquefying the tissue so the chigger can consume it. The body reacts to this foreign enzyme by forming a hardened, tube-like structure called a stylostome around the feeding site. The chigger then feeds through this stylostome, which acts like a drinking straw.
The intense itching is an allergic and inflammatory reaction to the injected enzyme and the stylostome itself. This stimulation of nerve endings creates a severe sensation that can last long after the chigger has dropped off. If the mite is not disturbed, it may feed for several days through the stylostome before detaching.
How to Identify a Chigger Bite
Chigger bites typically manifest as small, red welts, bumps, or pimple-like lesions. These irritated spots often appear in clusters or patches, sometimes with a bright red dot visible in the center, which represents the stylostome where the mite fed. The reaction is delayed, usually beginning three to six hours after the chigger has started feeding, making it difficult to pinpoint the exact moment of exposure.
Chigger bites are defined by their location in areas where clothing fits tightly. These areas restrict the mite’s movement and provide an easy feeding environment. Common hot spots include:
- The ankles
- Behind the knees
- The waistline
- The groin
- Under the arms
The severe, delayed itch and the clustering in tight-clothing areas help confirm identification, distinguishing them from other insect stings.
Treating the Bites and Relieving the Itch
Immediate relief starts with washing the affected area thoroughly with soap and water. This action removes any chigger larvae that may still be attached to the skin, preventing further enzyme injection, though it does not stop the existing itch. The itching is often most severe during the first 24 to 48 hours after the bite appears.
Over-the-counter anti-itch treatments are recommended to manage the irritation. Calamine lotion can help soothe the skin and dry out any weeping bites, while topical corticosteroid creams reduce inflammation. Oral antihistamines can be taken to lessen the body’s allergic reaction, especially if the itching interferes with sleep. Avoiding scratching is important, as breaking the skin can introduce bacteria and lead to a secondary infection; symptoms generally resolve within several days to two weeks.
Steps for Preventing Chigger Exposure
Preventing chigger bites involves creating a barrier against the mites when spending time outdoors in grassy or wooded environments. Wearing protective clothing, such as long-sleeved shirts and long pants, is an effective physical defense. Tucking the pant legs into socks or boots seals off a common entry point for mites climbing up from the ground.
Applying insect repellent to exposed skin is important, with products containing DEET being effective against chiggers. Clothing can be treated with permethrin, an insecticide that kills mites on contact. Permethrin should not be applied directly to the skin, but once it dries on fabric, its repellent properties can last through several washings. After being in a high-risk area, showering promptly and washing all worn clothes in hot water removes any clinging mites.