Chiggers, also called harvest mites or red bugs, live as adults in decaying vegetation. Only their larval forms are parasitic. Dogs acquire the infestation while prowling in forest grasslands and fields in late summer and fall, when chiggers are reproducing.
Chigger larvae appear as red, yellow, or orange specks, barely visible to the naked eye but easily seen with a magnifying glass. They tend to clump in areas where the skin is thin, usually between the toes or about the ears and mouth. The larvae feed by sucking on the skin. The result is severe itching and the formation of sores and scabs. The diagnosis is made by identifying the mites by visual inspection or by microscopic examination of skin scrapings.
Treatment: Chiggers respond well to a single application of a lime-sulfur dip (LymDyp) or a pyrethrin shampoo. Corticosteroids may be required for two or three days to control the intense itching. If the ear canals are involved, treat with thiabendazole drops (brand name Tresaderm). Prevent reinfestation by keeping your dog out of fields and grasses during the chigger season.