Photo by Karin Pedersen Photography

Mosquito bites are an annoying part of summer.  The best way to deal with mosquitoes is to prevent them from biting in the first place.  But there are some things you can do to alleviate the itch that follows if you do get bit. 

Why Are Mosquito Bites Itchy

The female mosquito is responsible for itchy mosquito bites.  She will inject saliva into the skin that contains enzymes that thin our blood so it is easier for her to suck blood out.  It is the chemicals in the mosquito saliva that cause the itchy welts on our skin.  It takes at least 6 seconds for a reaction to occur.  

A typical mosquito bite causes local histamine reactions – a welt or a hive.  A firm itchy bump on the skin with surrounding redness will develop within a few hours and may last a few days.  This is an example of a type I allergic reaction.  Some people develop larger blistering lesions or nodules, type IV allergic reactions, which can be extremely uncomfortable.  Mosquitoes very rarely cause anaphylaxis. 

Getting Rid of the Itch

Treatment of mosquito bites is aimed at easing the itch, pain and swelling.  No one product is proven better than another for bug bites.

One of the easiest things you can do for itchy mosquito bites is to apply cold compresses to the bump to help with swelling and pain.  It important to avoid scratching as much as possible to prevent infection of the bug bite.   

There are also different topical products available that may help with providing some itch relief.  No one is proven better than the other. A pharmacist can help you choose the right product for you and your family.  

Protectants (e.g. Calamine lotion)

  • Apply liberally as needed to the mosquito bite
  • Protect the skin and can help reduce swelling and inflammation
  • Soothe irritated skin
  • Well tolerated and not absorbed
  • Safe for use in babies 6 months and older

Ammonia/Baking Soda (e.g. Afterbite®)

  • Apply as needed to the mosquito bite
  • Provides a cooling sensation and some relief of itching
  • Can cause skin irritation.  Do not use near mucus membranes, eyes or mouth
  • Not recommended for children under the age of 2

Counterirritants like camphor or menthol (e.g. Gold Bond®)

  • Apply sparingly as needed to the mosquito bite
  • Provides a cooling sensation, some pain relief, and some anti-itch effects
  • May cause skin irritation
  • Not recommended for children under the age of 2

Topical anesthetics like pramoxine (e.g. Aveeno Anti-Itch®, Gold Bond®)

  • Apply sparingly up to four times a day as needed
  • Numbs the area applied to provide minor pain relief and anti-itch effects
  • May cause skin irritation
  • Not recommended for children under the age of 2

Topical hydrocortisone (e.g. Cortate®)

  • Available as 0.5% and 1% cream
  • Apply sparingly up to twice a day for 5-7 days for mild to moderate reactions
  • Reduces swelling and provides anti-itch effects
  • Do not use on children unless on the advice of a health care provider

Oral antihistamines

  • Cetirizine (Reactine®) or similar medications are preferred over diphenhydramine (Benadryl®) because they cause less sedation
  • Relieves itch and inflammation for 24 hours for moderate reactions
  • Approved for use in children 2 years and older
  • A physician may recommend it for children younger than 2

Severe Reactions Are Not Common

Mosquito bites rarely cause anything more than an itchy bump that lasts a few days.  Very rarely they can cause a large local reactions or systemic reaction.  If you develop any of the following symptoms within 30 minutes of a bug bite, you should seek medical attention:

  • Itching all over your body
  • Difficulty breathing
  • Hives
  • Nausea, vomiting, abdominal cramps
  • Dizziness, fainting
  • Hoarse voice or swelling in the throat
  • Changes in heart rate (fast or slow)

This post was co-authored by Stephanie Liu, MD, MSc, CCFP, BHSc and Erin Manchuk, BScPharm, BCGP .