The reason why some insect bites swell up

young female scratching her itching arm from a mosquito bite at the park during summertime
Here's why some insect bites swell up stefanamer - Getty Images

Summer (and going on holiday) is great and everything, but when that brings with it an army of approximately three million mosquitoes and midges - whose sole aim in life is to bite you to shreds - it can get pretty irritating.

And when these bites swell up, they become even more unsightly. Because let's face it, a serious case of bulbous-looking arms and legs due to unforgiving levels of swelling does not go well with any vacay wardrobe. Period.

But while appearance-wise, tender red lumps dotted all over your limbs are less than ideal, why do some insect bites swell up, but not all of them, and what actually causes it to happen?

Obviously, it would make sense to ask the UK’s leading insect expert, Dr James Logan for his take on the matter, which is exactly what we did. So, for those of you guys who are more susceptible to a nasty swell from a pesky bite, listen up...

woman applying medicine cream on mosquito bite on her leg allergic reaction, itch, irritation due to insect bite concepts
Ladanifer - Getty Images

Why do some insect bites swell up – but not all?

"Most people will get some small swelling from a bite. This is a normal reaction," Dr Logan says. However, "if the swelling gets bigger (more than 10cm) see a GP as this may be a sign of infection."

"Swelling can happen anywhere on the body," Dr Logan explains. And the actual cause for such swelling? Not to do with an allergic reaction to the bite, as you might have imagined, but because the swollen bites have become more externally irritated than the others." This - he labels - can be down to clothing or bedding rubbing against the bites.

As you'll well know, if the bites become irritated they often become more itchy "which can cause the reaction to get worse", Dr Logan explains. "Often areas around the arms and legs can be worse because the bites get rubbed by clothing and irritated."

Dr Logan's advice for irritated bites is, sadly, probably the same as your mum's: "Don’t scratch them."

If your bites do become swollen, you're advised to keep them "as clean as possible, use a cold compress and speak to a pharmacist about using antihistamines, painkillers and any inflammatories like ibuprofen."

How to treat a swollen insect bite

The NHS website also offers up some extra advice, suggesting that swollen bites can be treated by putting an ice pack wrapped in a cloth or a clean cloth soaked in cold water on the affected area for at least 20 minutes. However, firstly, if there's anything left in the actual bite area, the first thing you need to do is remove it carefully.

Other home-based treatments include keeping the area raised and using a hydrocortisone cream to reduce itching and swelling. Following these simple - yet effective - directions will not only decrease the risk of infection but also allow the swollen bite to get better within a matter of days.

Of course, should the bite not get any better, or get worse, like Dr Logan says, it's vital you seek the expert opinion of your GP who will be able to recommend the best next steps.

This article is not intended to be a substitute for professional medical advice or diagnosis. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

You Might Also Like