If you’ve ever been bitten by a mosquito, you know how uncomfortable it is. The tiny red bumps swell up almost immediately, creating an itching that, once you start scratching, only seems to get worse. The more you scratch, the more itching increases — starting a vicious cycle that can leave you irritated, sore and covered in swollen, red bumps.
Some people appear to be mosquito “magnets” — the insects gather around them wherever they are, leaving bites on any exposed skin — while other people are relatively unharmed from the bites and without itching.
But how do mosquitoes choose their prey and how can we repel them? We spoke to some experts and asked for their advice.
Why is a mosquito bite itchy?
When a mosquito bites, it pierces the skin using a special mouthpiece (proboscis) to suck blood. As the mosquito is feeding on your blood, it injects saliva into your skin, according to the US Centers for Disease Control and Prevention (CDC).
Leslie Vosshall, vice president and chief scientific officer at the Howard Hughes Medical Institute, explained that mosquito saliva has an anesthetic-like quality, so you don’t feel the sting until the insect flies away. In addition, it also has anticoagulants to keep your blood flowing without clotting.
“The saliva of mosquitoes has a lot of proteins; some are allergens,” Vosshall said, adding, “our body recognizes the mosquito protein as foreign, and our immune cells spring into action to try to fight it.”
It’s not the sting that causes the itch. In fact, it’s our body’s response to the mosquito’s foreign protein that it’s trying to fight off. This is why some people may only have a mild reaction to the stings, while others, who are more sensitive to the foreign protein, react with large areas of swelling that are more painful.
And there’s no need to get mad at the male mosquitoes, as only the females bite. And they do this to get a blood meal, as most females cannot produce eggs without that blood.
How do mosquitoes choose their prey?
Like most other blood-eating insects, mosquitoes can smell us from afar through the carbon dioxide we exhale, and that’s what brings them closer in the first place, according to Daniel Markowski, a consultant technician from the American Mosquito Control Association.
“Once they actually get close to a host, they use a variety of other clues to finally get to it,” he said. “This includes visual components like shapes, sizes and colors. This is why dark colors are not recommended in prime habitats because they stand out more, especially in relation to backgrounds and contrasts.”
Other chemical signals “including breath odors, microbiota byproducts on our skin or other general human odors like octenol, ammonia, caproic acid or lactic acid” combine with our carbon dioxide to make us more or less attractive to different mosquito species. , he added.
It’s likely a combination of a person’s carbon dioxide and other odors that attract mosquitoes, said Vosshall, who recently wrote a paper on “the unbreakable attraction of mosquitoes to humans.” But she said the jury still doesn’t know what exactly makes one person more attractive to a mosquito than another.
“This is something we’re working on — the amount and type of body odor a person exhales is likely the reason,” Vosshall said via email. “There are articles that claim it’s blood type, or blood sweetness, or gender (women are supposedly more attractive to mosquitoes), but nothing is conclusively proven.”
What to do to not make the itching worse?
“Don’t scratch” is the advice most experts and health professionals give. As difficult and sometimes unrealistic as it may seem, scratching inflames the skin, and inflammation makes the skin itch more.
“Scratching can also cause secondary infections and prolong irritation,” warned Markowski, adding that in extreme cases, people can be left with scars.
Instead, there are dozens of creams and sprays that promise itchiness relief, as well as home remedies and mosquito repellents, so choosing the one that’s right for you can often come down to trial and error.
“In general, all the various itching creams are very similar,” Markowski said. “I generally suggest that if you are highly allergic to mosquitoes, you may need a cream with diphenhydramine or a similar antihistamine.”
Vosshall recommended applying hot water to the bite as soon as possible. “Very hot water — as hot as you can stand it, but not so hot that it burns — ‘short-circuits’ the itch reflex,” she said.
“If you’re hiking and that’s not practical, a topical anesthetic gel of local lidocaine can be helpful to prevent the itchy feeling, as can an over-the-counter cortisone cream.”
While both experts said that many people prefer natural remedies or herbal products, they urged caution. There is no scientific evidence that these remedies work and they may come with their own precautions or side effects.
In fact, the best remedy to combat itching is to avoid a sting in the first place.
“Chemical repellants, including DEET (N,N-diethyl-meta-toluamide) or picaridin, are safe and highly effective,” Vosshall said. Markowski agreed, describing DEET as the “gold standard”, registered with the US Environmental Protection Agency and endorsed by the CDC.
However, he acknowledged some people’s concerns regarding the ingredient’s toxicity, adding: “As with all products, I suggest treating a small area first and making sure you don’t experience allergic reactions. Also, read the label and follow all usage guidelines.”
When to seek medical attention
Some people can have severe allergic reactions to mosquitoes, although in practice this is rare, Vosshall said. If you have severe symptoms, such as hives, breathing problems, or anaphylaxis, seek medical attention immediately.
You should also consult a doctor if you are planning to travel to a country where blood-borne pathogens such as the Zika virus and malaria are common. Mosquitoes can transmit some diseases from person to person, but a doctor will be able to advise you if vaccines or preventative treatments are available.
Source: CNN Brasil
