- Helge Riemann, MD
Helge Riemann, MD
- Mid Coast Dermatology, Brunswick, Maine
- Whitney A High, MD
Whitney A High, MD
- Associate Professor of Dermatology and Dermatopathology
- University of Colorado School of Medicine
- Section Editors
- Robert P Dellavalle, MD, PhD, MSPH
Robert P Dellavalle, MD, PhD, MSPH
- Section Editor — Dermatology
- Professor of Dermatology and Public Health
- Denver VA Medical Center, University of Colorado School of Medicine and Colorado School of Public Health
- Ted Rosen, MD
Ted Rosen, MD
- Section Editor — Infections and Infestations
- Professor, Department of Dermatology
- Baylor College of Medicine
Mites are small arachnids that include thousands of species, many of which parasitize animals and plants . In animals and humans, these mites may produce cutaneous lesions, yield allergic reactions, or act as vectors for infectious disease.
The recognition and management of bites from larvae of the Trombiculidae family (also known as "chiggers") will be reviewed here. Synonyms for these organisms include harvest mites, harvest bugs, harvest lice, Mower's mites, and redbugs [2,3]. The term "chigger" should not be confused with "jigger," a term which is typically used to refer to the chigoe flea (tunga penetrans). Other arthropod bites are reviewed separately. (See "Insect bites".)
The adult trombiculid mite is typically 1 to 2 mm in length, with a bright red or red-brown color (picture 1). The life cycle of the mite proceeds through egg, larval, nymphal, and adult stages . Only the larval stage is responsible for chigger bites.
Mite larvae are only 0.15 to 0.3 mm in length (picture 2). After hatching, the larvae reside on leaves or grass stems waiting for an animal or human to pass by. The larvae attach to the skin of the host organism and remain for up to a few days. Subsequently, the larvae drop to the ground to mature into the harmless nymphal and adult stages [1,4].
The nymphal stage is similar to, but smaller than, the adult form. Adults and nymphs live in the soil and feed on plants, other mites and small insects, and insect eggs.
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