Chiggers are tiny, almost invisible pests that can cause intensely itchy skin reactions. These sensations are not true “bites” in the traditional sense, but rather a reaction to the chigger’s feeding process. This article explores what chiggers are, how they interact with human skin, and how their presence can be identified.
Understanding Chiggers
Chiggers are the larval stage of certain mites belonging to the Trombiculidae family, making them relatives of spiders and ticks. These creatures are microscopic and nearly invisible to the unaided eye. They possess six legs in their larval form. Only this larval stage is parasitic to humans and animals.
Chiggers thrive in outdoor environments, particularly in areas with tall grasses, weeds, wooded regions, and damp conditions. They are most active during warm temperatures from late spring to early fall. Their activity decreases as temperatures drop.
The Mechanism of a Chigger “Bite”
Chiggers do not bite or burrow into the skin like ticks. Instead, when a chigger larva encounters a host, it attaches to the skin, often in areas where clothing fits tightly or in skin folds, such as around ankles, waistbands, or armpits. Once attached, the chigger injects digestive enzymes into the skin. These enzymes break down skin cells, creating a liquefied channel.
This process forms a hardened tube of dead skin cells, called a “stylostome.” The chigger then feeds on this dissolved tissue, not blood, by sucking up the liquefied cells through the stylostome. The intense itching and red welts are an allergic reaction to these injected enzymes, not to the chigger itself or its feeding on blood. If undisturbed, a chigger may feed for several days before detaching, but scratching often dislodges them earlier.
Identifying Chigger Bites
Chigger reactions manifest as small, red bumps or welts that can resemble pimples, blisters, or hives. These reactions are characterized by intense itchiness, which can increase over several days. The itch often begins hours after exposure, as the body reacts to the enzymes.
Bites appear in clusters and are found on areas of the body where clothing is tight or where skin folds exist. These locations include the ankles, lower legs, behind the knees, waist, groin, and armpits. The delayed onset of symptoms means individuals may not immediately associate the discomfort with their outdoor activity.