First aid: Insect bites and stings

Signs and symptoms of an insect bite result from the injection of venom or other substances into your skin. The venom sometimes triggers an allergic reaction. The severity of your reaction depends on your sensitivity to the insect venom or substance and whether you've been stung or bitten more than once.

Most reactions to insect bites are mild, causing little more than an annoying itching or stinging sensation and mild swelling that disappear within a day or so. A delayed reaction may cause fever, hives, painful joints and swollen glands. You might experience both the immediate and the delayed reactions from the same insect bite or sting. Only a small percentage of people develop severe reactions (anaphylaxis) to insect venom. Signs and symptoms of a severe reaction include:

• Nausea
• Facial swelling
• Difficulty breathing
• Abdominal pain
• Deterioration of blood pressure and circulation (shock)

Bites from bees, wasps, hornets, yellow jackets and fire ants are typically the most troublesome. Bites from mosquitoes, ticks, biting flies and some spiders also can cause reactions, but these are generally milder. Although rare, some insects also carry disease such as West Nile virus or Lyme disease.

For mild reactions

• Move to a safe area to avoid more stings.
• Remove the stinger, especially if it's stuck in your skin. This will prevent the release of more venom. Wash area with soap and water.
• Apply a cold pack or cloth filled with ice to reduce pain and swelling.
• Apply hydrocortisone cream (0.5 percent or 1 percent), calamine lotion or a baking soda paste — with a ratio of 3 teaspoons (15 milliliters) baking soda to 1 teaspoon (5 milliliters) water — to the bite or sting several times a day until symptoms subside.
• Take an antihistamine containing diphenhydramine (Benadryl, Tylenol Severe Allergy) or chlorpheniramine maleate (Chlor-Trimeton, Actifed).

Allergic reactions may include mild nausea and intestinal cramps, diarrhea, or swelling larger than 2 inches (5 centimeters) in diameter at the site. See your doctor promptly if you experience any of these signs and symptoms.

For severe reactions
Severe reactions may progress rapidly. Call 911 or emergency medical assistance if the following signs or symptoms occur:

• Difficulty breathing
• Swelling of the lips or throat
• Faintness
• Dizziness
• Confusion
• Rapid heartbeat
• Hives
• Nausea, cramps and vomiting

Take these actions immediately while waiting with an affected person for medical help:

1. Check for medications that the person might be carrying to treat an allergic attack, such as an auto-injector of epinephrine (for example, EpiPen). Administer the drug as directed — usually by pressing the auto-injector against the person's thigh and holding it in place for several seconds. Massage the injection site for 10 seconds to enhance absorption.
2. Have the person take an antihistamine pill if he or she is able to do so without choking. Do this after administering epinephrine.
3. Have the person lie still on his or her back with feet higher than the head.
4. Loosen tight clothing and cover the person with a blanket. Don't give anything to drink.
5. Turn the person on his or her side to prevent choking if there's vomiting or bleeding from the mouth.
6. Begin CPR if there are no signs of circulation, such as breathing, coughing or movement.

If your doctor has prescribed an auto-injector of epinephrine, read the instructions before a problem develops and also have your household members read them.

Related

• Anaphylaxis
• Bee stings