The more common biting non-tick arthropods in the US include sand flies, horseflies, deerflies, blackflies, stable flies, mosquitoes, fleas, kissing bugs, lice (see Parasitic Skin Infections: Lice), bedbugs, wheel bugs, and certain water bugs. All of these arthropods, except wheel bugs and water bugs, also suck blood, but none is venomous.

Arthropod saliva composition varies considerably, and the lesions caused by bites vary from small papules to large ulcers with swelling and acute pain. Dermatitis may also occur. Most serious consequences result from hypersensitivity reactions or infection; in sensitized people, they can be fatal. Flea allergens may trigger respiratory allergy even without a bite in some people.

The location and pattern of wheals and lesions are sometimes diagnostic of the bite source. For example, blackfly bites are usually on the neck, ears, and face; flea bites may be numerous, mostly on the feet and legs; and bedbug bites often occur in linear patterns, most commonly on the torso.

The bite should be cleaned, and an antihistamine or corticosteroid cream or ointment should be applied for itching. Severe hypersensitivity reactions should be treated (see Allergic, Autoimmune, and Other Hypersensitivity Disorders: Treatment).

Last full review/revision February 2013 by Robert A. Barish, MD, MBA; Thomas Arnold, MD