To the dismay of farmers, gardeners, campers, hikers and music festival attendees, chigger season is underway across the American Heartland. Chiggers are the larval forms of a mite that favors pastures, fields, grasslands and lawns, especially in warm, humid areas; the female mite lays her eggs on vegetation which hatch to release the larvae. The latter feed on skin cells of mammals (humans included) before maturing into nymphs and then adults.
Chiggers feast on the skin cells by injecting an enzyme that breaks down the cellular structure, allowing the larvae to ingest nutrients; these "bites" trigger an inflammatory reaction, producing red bumps or welts that appear 24-48 hours after the infestation. As many of us know, this rash is extremely pruritic if not painful; the intense inflammatory response generally fades within a few days.
Those who venture into chigger habitat are advised to shower and wash their clothes in hot water as soon as their activity is completed; of course, this is not always possible for campers and festival attendees. For those "bitten" by chiggers, cool compresses, anti-inflammatory meds (e.g. ibuprofen) and anti-pruritic agents (e.g. diphenhydramine, topical hydrocortisone) are recommended; avoid excessive scratching which can lead to secondary bacterial infection. Fever, expanding redness or pustular drainage are signs of infection and warrant medical attention.