Insect Bite  
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This Care Guide Covers:

  • Itching, pain, or swelling from an insect bite

If not, see these topics
View First Aid Advice
  • for Anaphylaxis - Epinephrine
  • for Anaphylaxis - Benadryl
  • for Anaphylactic Shock

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Female Mosquito
Female Mosquito

When to Call Your Doctor

Call 911 Now (you may need an ambulance) If
  • Passed out (fainted)
  • Trouble waking up or acting confused
  • Trouble breathing or wheezing
  • Hoarseness, cough, or tightness in the throat or chest
  • Swollen tongue or trouble swallowing
  • Past severe allergic reaction to the same insect bite (not just hives or swelling)
  • Note: The above are signs of anaphylaxis. Anaphylaxis most often starts within 20 minutes, and always by 2 hours after a sting. See First Aid.
  • You think you have a life-threatening emergency
Call Your Doctor Now (night or day) If
  • You feel weak or very sick
  • Hives or swelling on the body
  • Severe bite pain that is not better 2 hours after pain medicine
  • Redness and sting site is tender to touch and have a fever
Call Your Doctor Within 24 Hours (between 9 am and 4 pm) If
  • You think you need to be seen
  • Sting site is red or very tender to touch and this started over 24 hours after the bite
  • Sting site is red or very tender to touch and it is getting larger over 48 hours after the bite
Call Your Doctor During Weekday Office Hours If
  • You have other questions or concerns
  • Scab drains pus or gets bigger and is not better after using antibiotic ointment for 2 days
Self Care at Home If
  • Normal insect bite
  • Scab drains pus or gets bigger in size
Causes & Health Information

Some Basics...

Types of Insect Bites

What are No-See-Ums?

What are Chiggers?

What are Bed Bugs?

CARE ADVICE

Treatment for Insect Bites
  1. What You Should Know:
    • In most cases, insect bites only cause a minor reaction at the bite site.
    • Scratching at a bite only irritates the area even more. It is the saliva the insect leaves behind that makes the itchy bump. Scratching at it can make it worse. So, try not to scratch!
    • You can treat minor reactions at the bite site at home.
    • Here is some care advice that should help.
  2. Treating Itchy Insect Bites:
    • Put calamine lotion or a baking soda paste on the bite.
    • If the itch is severe, put on 1% hydrocortisone cream. Do this 4 times a day until it is less itchy. Then switch to calamine lotion.
    • Try putting firm, sharp, steady pressure on the bite for 10 seconds. A fingernail, pen cap, or other object can be used.
  3. Antihistamine Drugs for Severe Itching: Take an antihistamine to help with the itching. Diphenhydramine (Benadryl) is a good choice. It is sold over-the-counter (OTC). The adult dose is 25-50 mg. You can take it up to 4 times a day.
    • Caution: Do not take these drugs if you have an enlarged prostate. They may make you feel tired. Do not drink, drive, or use dangerous machinery while taking antihistamines.
    • Two OTC antihistamines that cause less sleepiness are cetririzine (Zyrtec) and loratadine (Alavert or Claritin).
    • Read all package instructions.
  4. Treating Painful Insect Bites:
    • Rub the bite with a cotton ball soaked in a baking soda solution. Do this for 15-20 minutes. This will most often help with the pain. Do not use near the eye.
    • Another choice is to put an ice cube on the bite for 20 minutes.
  5. Pain Medicines:
    • You can take one of the drugs listed below if you have pain.
    • They are over-the-counter (OTC) pain drugs. You can buy them at the drugstore.
    Acetaminophen (Tylenol):
    • Regular Strength Tylenol: Take 2 pills (650 mg) every 4-6 hours. Each pill has 325 mg of acetaminophen.
    • Extra Strength Tylenol: Take 2 pills (1,000 mg) every 8 hours. Each pill has 500 mg of acetaminophen.
    • Do not take more than (3,000 mg) of this drug per day.
    Ibuprofen (Motrin, Advil):
    • Motrin and Advil: Take 2 pills (400 mg) every 6 hours. Each pill has 200 mg of ibuprofen.
    • A second choice is to take 3 pills (600 mg) every 8 hours.
    Naproxen (Aleve):
    • Aleve: Take 1 pill (220 mg) every 8 hours. Each pill has 220 mg of naproxen.
    • A second choice is to take 2 pills (440 mg) every 12 hours.
    Extra Notes:
    • Use the lowest amount of a drug that makes your pain feel better.
    • Your doctor might tell you to take more than what is shown above. That is because your doctor knows you and your health problems.
    • Acetaminophen is safer than ibuprofen or naproxen in people over 65 years old. Acetaminophen is in many OTC and prescription drugs. It might be in more than one drug you are taking. Be careful how much you take. Too much of this drug can hurt the liver.
    • Caution- Acetaminophen: Do not take it if you have liver disease.
    • Caution- Ibuprofen and Naproxen:
      • Do not take ibuprofen or naproxen if you are pregnant.
      • Do not take these drugs if you have stomach problems or kidney disease.
      • Do not take these drugs for more than 7 days without checking with your doctor.
    • Read all package instructions.
  6. What to Expect:
    • Most insect bites itch or hurt for 1-2 days.
    • The swelling may last a week.
  7. Call Your Doctor If:
    • Severe pain lasts more than 2 hours after pain medicine
    • Infected scab is not better after 48 hours of antibiotic ointment
    • Bite looks infected (redness, red streaks, or is tender to touch)
    • You get worse
Infected Sore or Scab
  1. What You Should Know:
    • Sometimes an insect bite can get infected a couple days after the bite. An infection does not start in the first 1-2 days.
    • Signs of an infection are redness, tenderness to touch, and a scab that does not go away. An infected sore is often covered by a soft, 'honey-yellow,' or yellow-brown crust or scab. Sometimes the scab may drain a tiny amount pus or yellow fluid. If there is pain, it is mild.
    • These sores should get better with daily cleaning and antibiotic ointment.
    • You can treat a minor infection of an insect bite at home.
    • Here is some care advice that should help.
  2. Cleaning:
    • Wash the bite 2-3 times daily with antibacterial soap and warm water.
    • Gently remove any scab. The bacteria live under the scab. You may need to soak the scab off. Do this by placing a warm wet washcloth on the sore for 10 minutes. You can also use gauze.
  3. Antibiotic Ointment:
    • Put an antibiotic ointment on the sore 3 times per day.
    • Cover the sore with an adhesive bandage (Band-Aid) to avoid scratching and spreading.
    • Use Bacitracin ointment (OTC in the United States) or Polysporin ointment (OTC in Canada). You can also use one that you have.
  4. Avoid Picking: Avoid scratching and picking. This can worsen and spread a skin infection.
  5. How It Is Spread:
    • Infected sores can be spread by skin to skin contact.
    • Wash your hands often and avoid touching the sore.
    • Work and School: You can go if the sore is covered.
    • Sports: You need to get antibiotic treatment for 3 days before you can play. There can be no pus or drainage. You should check with your trainer, if there is one for your sports team.
  6. What to Expect:
    • The sore should stop growing in 1-2 days. It should start to get better within 2-3 days.
    • The sore should be healed in 7-10 days.
  7. Call Your Doctor If:
    • Have a fever
    • Spreading redness or a red streak
    • Sore gets bigger
    • Sore is not better after using antibiotic ointment for 2 days
    • Sore is not healed in 7 days (1 week)
    • New sore appears
    • You get worse
Preventing Insect Bites
  1. Prevention:
    • Wear long pants and long-sleeved shirts.
    • Avoid being outside when the insect is most active. Many insects that cause itchy bites are most active at sunrise or sunset. These include Chiggers, No-See-Ums, and Mosquitoes.
    • Insect repellents with DEET in them work well to prevent many itchy insect bites.
  2. DEET:
    • DEET is a very strong insect repellent. It also repels ticks.
    • Higher strength DEET works better. All DEET over 50% works the same. For children and teens, the American Academy of Pediatrics recommends a maximum strength of 30%. Health Canada recommends using a strength of 5-30% for adults.
    • Spray on exposed areas of skin. Do not put near your eyes, mouth or any irritated skin. Do not put it on skin that is covered by clothing.
    • Always wash it off with soap and water when you return indoors.
    • DEET can damage clothing made of synthetic fibers, plastics, and leather.
    • Women that are breastfeeding may use DEET. No problems have been found.
    • Read all label instructions.
  3. Picaridin (KBR 3023):
    • Research shows that it works just as well as DEET.
    • It has been used in other countries for years.
    • Read all label instructions.
West Nile Virus (WNV) Information
  1. Symptoms of WNV:
    • No clinical symptoms: 80% of WNV cases.
    • Mild febrile illness: 20% of WNV cases. Symptoms include fever, headache, body aches, and sometimes a skin rash. These last 3-6 days and go away without any treatment. This is also called WNV fever.
    • Encephalitis or viral meningitis: 0.7% of WNV cases. Symptoms are high fever, stiff neck, confusion, coma, convulsions, muscle weakness, or paralysis. The muscle weakness is often on one side of your body. These symptoms are easy to see.
    • Fatal: 10% of those who are hospitalized will die.
    • Pediatric cases are most often mild. Most encephalitis and deaths happen to people over age 60.
  2. Diagnosis of WNV:
    • Mild cases do not need to be diagnosed.
    • Severe cases (with encephalitis and viral meningitis) will be hospitalized based on their symptoms. The disease is diagnosed by tests on the blood and spinal fluid. These tests are not used for the normal mild infections seen with this virus.
  3. Treatment of WNV:
    • No special treatment is needed after a mosquito bite.
    • There is no anti-viral agent for WNV.
    • WNV patients in the hospital are given IV fluids, airway control, and care.
    • There is no vaccine that can prevent WNV in humans.
  4. How WNV Is Spread:
    • The West Nile virus is spread by the bite of a mosquito. The virus comes from infected birds.
    • Even in an area with WNV, less than 1% of mosquitoes carry it.
    • The virus is spread from mosquito-to-human.
    • You cannot spread WNV to other people. It is not spread by kissing, touching, sex, or sharing glassware.
    • Mothers with mosquito bites can keep breastfeeding.
    • Symptoms will show 3-14 days after the mosquito bite.

Remember! Call your doctor if any of the "When to Call" symptoms occur.

Disclaimer: This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.


Author and Senior Reviewer: David A. Thompson, M.D.

Last Reviewed: 9/1/2012

Last Revised: 11/15/2012

Content Set: Adult Symptom Checker

Copyright 2000-2012. Self Care Decisions LLC; LMS, Inc.