Chigger bites are a regular summertime annoyance in Central Virginia. Most commonly found in grassy fields, gardens, forest areas, and parks, chiggers thrive in moist, vegetated areas with high humidity, hitching a ride on the unsuspecting human passer-by.
Also called the harvest mite or red mite, chiggers are the six-legged, wingless larva form of the Trombiculidae mite. They are arachnids, like ticks and spiders. Barely visible to the naked eye, chiggers are red in color and may only be seen if they are clustered together on the skin or a plant.
The mites will attach to the skin or clothing of a passing human. They will then migrate to an optimal feeding area on the skin. Usually bites will be seen in areas where the skin is relatively thin: the ankles, groin, waist, behind the knees, and in the armpits. Because tight clothing such as waist bands and belts prevent mite migration, bites will often be seen in these areas.
It is a common misconception that chiggers burrow into and remain in the skin. What they do is to insert their feeding structures (stylostome) into the skin and inject an enzyme that will break down the host tissue. The chigger then feeds off the degraded tissue. If undisturbed, the mites can stay attached for a few days.
The introduction of the stylostome and injection of the enzyme into the skin both cause local irritation in the area of the bite. Symptoms of intense itching and redness can occur within one to three hours of a chigger bite. Scratching of the skin usually dislodges the chiggers and prevents them from staying attached for long periods of time. Home remedies of applying nail polish, alcohol, or bleach in an attempt to suffocate the chiggers are not effective.
Treatment of chigger bites is normally aimed at relieving the itch. Topical over-the-counter medications such as calamine lotion and mild cortisone creams are generally useful choices. Antihistamine pills can be used for itching as well. This includes medications such as diphenhydramine (Benadryl). Itching can be expected to persist for several days.
Complications from chigger bites rarely occur. However, skin areas that are severely scratched by the sufferer may be prone to secondary bacterial infections. Check with your physician if the bitten area becomes increasingly red, hot, firm, or develops drainage.
When planning outdoor activities during the summertime you can minimize your risk of getting chigger or other insect bites by applying insect repellant. Those repellants that contain DEET have been found to be the most effective. Keeping skin covered as much as possible by wearing long sleeves and pants can also prevent bites. Finally, if you think you have been exposed to chiggers, wash the skin with soap and water to remove any mites and wash the clothing you were wearing as well.
The content in this column is for informational purposes only. Consult your physician for appropriate individual treatment. Dr. Reynolds practices Family Medicine in Chesterfield.