Skip to Content

Insect Bites


Robert A. Barish

, MD, MBA, University of Illinois at Chicago;

Thomas Arnold

, MD, Department of Emergency Medicine, LSU Health Sciences Center Shreveport

Last full review/revision May 2020| Content last modified May 2020

Among the more common biting insects in the United States are the following:

  • Sand flies
  • Horseflies
  • Deerflies
  • Blackflies
  • Stable flies
  • Mosquitoes
  • Fleas
  • Lice
  • Bedbugs
  • Kissing bugs
  • Wheel bugs
  • Certain water bugs

Ticks, spiders, and mites are not insects.

(See also Introduction to Bites and Stings.)

All of these, except wheel bugs and water bugs, also suck blood, but none is venomous. The bites of these insects may be irritating because of the components of their saliva. Most bites result in nothing more than a small, red, itchy bump. Sometimes, people develop a large sore (ulcer), with swelling and pain. The most severe reactions occur in people who are allergic to the bites or who develop an infection after being bitten. Fleas can cause allergic reactions sometimes without biting.

The bite should be cleaned, and an ointment or cream containing an antihistamine, an anesthetic, a corticosteroid, or a combination may be applied to relieve itching, pain, and inflammation. People with multiple bites can take an antihistamine by mouth. People who are allergic to the bite should seek medical attention immediately or use an emergency allergy kit containing a preloaded syringe of epinephrine.

Infectious Disease Spread by Insects

More significant than the bites themselves, certain insect bites in certain parts of the world can spread infectious disease. The following are some examples:

Mosquito bites can transmit several diseases, including

Flea bites can transmit

Lice may transmit

Some other insect bites and the diseases they can cause include

Drugs Mentioned In This Article

Generic Name Select Brand Names
epinephrine ADRENALIN

Copyright © 2022 Merck & Co., Inc., known as MSD outside of the US, Kenilworth, New Jersey, USA. All rights reserved. Merck Manual Disclaimer