Insect bites

Insect bites and stings Insect bites and stings

Insect bites and stings occur when an insect feeds off a person’s skin or tries to defend itself.

Different insects bite and sting in different ways. Common biting or stinging insects include mosquitoes, blackflies, bed bugs, fleas, ticks, fire ants, bees and wasps. Bees often leave stingers in the wound.

Insect bites usually cause mild swelling, redness and itchiness limited to the small area around the bite or sting. Some children, however, can experience potentially life-threatening reactions. This is called an anaphylactic reaction and requires immediate medical attention. In children who are at risk, anaphylaxis is most commonly caused by bees, wasps and hornets. Other insects can transmit disease. For example, some mosquitoes can transmit malaria or West Nile virus and some ticks can transmit Lyme disease​.​

Signs and symptoms of an insect bite or sting

Signs and symptoms of insect bites and stings vary according to the type of insect and your child’s reaction.

Normally, an insect bite or sting causes:

  • a small, red, raised bump, pimple or blisters
  • itchiness and irritation around the bump.

The symptoms can last from a few hours up to two days.

Some children develop a big firm swollen area around the bite. This is not an allergic reaction. It is known as a large local reaction and rarely leads to a skin infection.

If your child has an anaphylactic reaction, they may develop hives, facial or mouth swelling or breathing problems or they may collapse. Use an epinephrine auto-injector, if your child has one, and call for emergency assistance.

How to treat insect bites and stings

  • Cold, damp compresses or ice can relieve some of the swelling.
  • Over-the counter topical medications (medications you put on the skin) may also help to relieve the itch.

Some children may respond well to antihistamine medication for itching, but this medication can cause drowsiness.

When to see a doctor after an insect bite or sting

If your child has been bitten or stung, see a doctor right away if:

  • you are in an area where the insects are known to transmit diseases
  • your child develops an unusual rash, a fever or other symptoms.

Preventing insect bites and stings

Your child is more likely to be bitten or stung in warm and damp weather and in the evening and at night. Here are some ways you can reduce your child’s exposure to insects.

  • Apply insecticide or insect repellent to clothing and exposed skin.
  • Wear long pants and socks.
  • Wear light-coloured clothing.
  • Avoid areas where insects breed and live.
  • Stay inside when insects are most active.
  • Use insecticide-impregnated mosquito nets, especially for infants aged less than six months.
  • Take specific precautions, such as taking anti-malarial medications, as needed.

Be careful with DEET insect repellent

DEET is one of the most effective repellents for mosquitoes and biting flies, but it should be used with caution for children.

  • Babies less than six months old: Do not use any insect repellents with DEET.
  • Children aged six months to two years: Use a product with 10 per cent DEET or less and apply it once a day.
  • Children aged two to 12 years: Use a product with 10 per cent DEET or less and apply it no more than three times a day.
  • Children aged over 12: Use a product with up to 30 per cent DEET.

The higher the amount of DEET, the longer the protection will last.

How to apply DEET to your child's skin

  • Apply it to exposed skin, following the manufacturer's instructions.
  • Do not apply it to your child's face or hands or any areas where the skin is cut, grazed or irritated.
  • Once the DEET is applied, wash hands and avoid touching the lips and eyes.

How to use insect repellent and sunscreen effectively

  • Apply sunscreen about 30 minutes before you apply any insect repellent.
  • Do not use a single product that combines insect repellent with sunscreen. The insect repellent can make the sunscreen less effective and the sunscreen can increase how much insect repellent is absorbed by the body.​ In addition, you will normally need to apply sunscreen every two to three hours; it is not safe to apply insect repellent as frequently.

Key points

  • Insect bites often cause swelling and redness. Some children experience severe and potentially life-threatening reactions.
  • Common biting or stinging insects include mosquitoes, blackflies, bees and wasps.
  • Some children respond well to antihistamine medication; others may just need some ice.
  • Prevent insect bites and stings by covering the body with light-coloured clothing and applying insect repellent to exposed skin.
  • DEET is a very effective insect repellent, but use it carefully according to your child's age. If using sunscreen and insect repellent, apply sunscreen first.

​Shawna Silver, MD, FRCPC, FAAP, PEng



Health Canada. Insect bite preve​ntion​