What is mosquito bite allergy?
Mosquitoes live on every continent except Antarctica and cause most of the world’s insect bites. It’s normal to get a bump and itching after a mozzy bite. Stronger reactions could mean you have a mosquito bite allergy. It’s rare and happens more with children and people who have weakened immune systems.
So let’s look at ways to avoid bug bites and what to do if you get mosquito bite allergy symptoms.
How do mosquito bites cause allergic reactions?
The hungry mosquito pushes the tip of its proboscis or mouth through your skin and into a blood vessel. Then it injects saliva to stop your blood clotting while it feeds.
Your immune system overreacts to substances known as allergens in the mosquito’s saliva. It creates Immunoglobulin E (IgE) antibodies to defend you against them. Next time you get bitten you could develop mosquito bite allergy.
If that happens, the IgE antibodies tell other cells to release chemicals including histamine. And you may get mosquito bite allergy symptoms like pain, redness and swelling, around the bite site or allergic reactions elsewhere in your body.
Mosquito bite allergy symptoms
Mosquito bites are those itchy bumps that pop up minutes after someone gets bitten. In a day or so, the bump may go hard and change colour. It could also turn into a small blister or cause a darker mark that looks like a bruise. These are all common symptoms of a mosquito bite.
A stronger reaction suggesting a mosquito bite allergy usually develops within hours. It may look like this:
- large local reaction with swelling and redness (less visible on darker skin types)
- slight fever
- swollen lymph nodes (glands)
- rash or little red raised bumps on your skin (hives)
Mosquito bite allergy symptoms are sometimes mistaken for bacterial cellulitis. This happens more often in very young children who may have stronger reactions to bites than adults. But cellulitis usually takes days to develop. Scratching mosquito bites can cause it.
Why do I suddenly have mosquito bite allergy?
It may seem sudden but you must have already had those IgE antibodies we spoke about. You usually need to be bitten by a mosquito at least twice to develop an allergy. The first bite puts the body on alert. This is called sensitisation. Not all people who become sensitised will go on to have allergic reactions. It’s not yet understood why some people become allergic and others don’t.
Children are likelier than adults to have the more severe allergic reactions to mosquito bites. That may partly be due to something called natural desensitisation. Everyone experiences allergy differently. And some people may very gradually stop reacting to bites in the same way after long exposure to the same species. Bites from a different kind of mosquitoes, on holiday for instance, could still cause more severe reactions.
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Diagnosing a mosquito bite allergy
Testing for mosquito bite allergy is not well developed as it is for common allergies such as pollen or dust mites. Your GP will probably make their diagnosis by looking at the bites and taking your medical history. They may ask about your worst bite reaction to help predict the likelihood of a severe allergic reaction in the future.
Seven simple mosquito bite allergy tips
Be the anti-mosquito hero and help your friends and family avoid being bitten too. Here are some basic dos and don’ts:
- Don’t venture into enemy territory: Pools of standing water and shady humid places are often mosquito hotspots. Empty the paddling pool at least once a week if your child has mosquito bite allergy.
- Do cover up: Wear long-sleeved shirts and long trousers so there’s less exposed skin for mosquitoes to land on.
- Don’t draw attention to yourself: Bright clothes and strong perfume can attract mosquitoes.
- Do plan any exercise carefully: A person’s sweat, the release of lactic acid and exhaled carbon dioxide are irresistible to mosquitoes. So think about when to go out for a run and what to wear to avoid being bitten and having mosquito bite allergy symptoms.
- Don’t be too much of a night owl: Mosquitoes are most active from dusk to dawn so stay indoors if you can.
- Do use a mosquito net: It must have at least 24 holes per square centimetre to be effective.
- Don’t hold back with the bug spray: Look for insect repellents containing DEET. It might be in the ingredients as N, N-diethyl-meta-toluamide. Find the lowest concentration that works for you. Treat clothing and camping gear too. Icaridin or lemon eucalyptus oil may also work on skin. But only use DEET on babies over two months old and lemon eucalyptus on children over three.
Be a little careful how you apply insect repellent. It can irritate cuts, scrapes and grazes, sunburn and rashes. Eyes too. Keep it away from childrens’ hands and faces. DEET can also cause irritation if left on the skin for a long time. So wash off the repellent with soap and water as soon as you’re back indoors.
Treatment for mosquito bite allergy symptoms
Sometimes, no matter what you try, it’s impossible to prevent mosquito bites. Most local reactions can be treated with home remedies. Raise the affected area and apply an ice pack for 10 minutes to reduce pain and swelling. You can do this as often as needed. Clean blisters with soap and water, making sure not to break them. For itching, try calamine lotion. Or dab on a paste of baking soda and water. Leave on the bite area for 10 minutes, then rinse off.
There are symptom-relieving allergy medicines if you need them. An over-the-counter antihistamine cream can relieve itching. Hydrocortisone cream, which is a type of corticosteroid, may reduce swelling, and itching.
Speak to your GP if the swelling spreads or you think the bite area could be infected. Telltale signs include your skin feeling warm and a red streak moving outward from the bite. They can also advise on which antihistamine may be best as a preventative measure when you know you’ll be exposed to mosquitoes. This may help if you do tend to have bigger reactions.
Mosquito bite allergy: Severe reactions
Mosquitoes are more likely than many other biting insects to cause anaphylaxis. But severe allergic reactions affecting the whole body are still very rare (unlike with insect sting allergy). Symptoms that could be part of a more serious reaction and a medical emergency include:
- skin feels clammy
- lightheadedness, fainting or losing consciousness
- fast heartbeat
- wheezing and difficulty breathing like fast or shallow
- anxiety or confusion
Adrenaline is the main medicine used to treat anaphylaxis. Your GP may prescribe an auto-injector if you’re considered at risk of a severe allergic reaction.
It’s a good idea to carry two auto-injectors with you in case a single dose is not enough. Your friends and family may need to help you use it so show them how it works. You should also go to hospital even if the epinephrine makes you feel better.
