Why Mosquito Bites Itch and How to Get Relief

Few pests can ruin a lovely summer outing like the mosquito. No place in America is safe from at least one variety of these flying bloodsuckers, and their bite can transmit a range of diseases — from West Nile virus and dengue fever to Zika — as well as leave the victim with an itchy, inflamed, red welt.

A recent report from the Centers for Disease Control and Prevention (CDC) found that diseases transmitted by mosquitoes and other biting bugs more than tripled between 2004 and 2016. But while mosquitoes are ubiquitous in America and pretty much everywhere else, understanding where they live, how they hunt, and when they come out to feed can help you avoid being bitten. (1)

RELATED: Everything You Need to Know About Bug Bites and Related Diseases

Why Do Mosquito Bites Itch So Much?

Only female mosquitoes bite. And their mouths are intricate, multipart instruments. (2)

Known formally as a proboscis, the female mosquito’s mouth is made up of a bundle of long, tapered feeding stylets that act like microscopic syringes — sucking out the blood that females require to produce their eggs.

As the mosquito extracts this blood, it also pumps its saliva into the bite site, says Jonathan Day, PhD, a professor emeritus of medical entomology at the University of Florida. This saliva contains proteins that prevent the bite from clotting, which would slow the outflow of blood and therefore disrupt feeding, Dr. Day explains.

Apart from stopping blood from clotting, these saliva proteins also elicit a reaction from the bite victim’s immune system. Specifically, the human immune system releases a compound called histamine, which promotes inflammation and allows wound-repairing white blood cells to flood the area of the injury. It’s this histamine-releasing immune reaction that causes all your bug bite symptoms.

The swelling, redness, and itch are the body’s responses to those foreign proteins, Day explains.

RELATED: How to ID These 13 Common Bug Bites and Stings

Rubbing Alcohol, Calamine Lotion, and Other OTC Creams Can Help Relieve the Itch

First of all, try your best not to scratch your itchy bug bite. That will only further inflame the lesion, and make the itching, swelling, and irritation worse, Day says.

Instead, he recommends dabbing the bite with rubbing alcohol. By denaturing the proteins in the bite, rubbing alcohol “works really well in reducing swelling and the histamine response,” he says. “In the field, I always carry those little individually packaged alcohol swabs, and they really help me.”

Along with quelling the immune reaction to a bite, rubbing alcohol also has a cooling, soothing effect, Day says. Rubbing an ice cube on the bite site could likewise offer some temporary relief — although that won’t remove any of the mosquito’s proteins, he says.

Calamine lotion can also relieve the itch, says Lee Townsend, PhD, a professor emeritus of entomology at the University of Kentucky. The same is true of over-the-counter hydrocortisone creams, which help mellow the body’s natural immune response to the mosquito proteins.

If you have a lot of bites and are really suffering, an oral antihistamine — something like diphenhydramine (Benadryl) or cetirizine (Zyrtec) — can also quell your body’s response to a bite. (3)

Complications That Can Arise From Mosquito Bites

A handful of serious complications can occur following a mosquito bite. As mentioned above, infections or viruses like dengue and Zika are often contracted via a mosquito bite. Unfortunately, symptoms of these diseases are often nonspecific — meaning they’re indicators that can result from a wide variety of health issues, making it hard to know if a mosquito bite is to blame. For example, both dengue and Zika can produce headaches, fever, joint pain, and skin rashes. But the same is true of the common flu and many other viruses or infections. (4,5)

In general, the CDC recommends visiting a doctor if any flu or skin symptoms emerge in the week following a mosquito bite — especially if this occurs during the summer when the incidence of common flu is low. (6)

For most bite victims, the most likely complication of a mosquito bite is a secondary bacterial infection caused by scratching with dirty fingernails. Day says this is especially true for children, who tend to have heightened skin reactions to mosquito bites, and who are also likelier than adults to have filthy nails.

If a bite’s swelling and redness don’t subside within a day or two — and especially if it seems to be getting worse, not better — that’s a sign of a bacterial infection. The person should see a doctor, who will likely prescribe oral or topical antibiotics, Day says.

Tips for How to Avoid Getting Mosquito Bites in the First Place

To minimize your bite risk, try to stay indoors at dawn and dusk — times when humidity often peaks. “The higher the humidity, the better for mosquitoes, so dawn and dusk are times when they tend to be active,” Day says.

He explains that mosquitoes are fragile insects, and their bodies dry out quickly if they’re exposed to arid conditions or extended stretches of bright sunlight (which is another reason they prefer hunting at dawn and dusk, as opposed to midday). They’re also weak fliers, he says, so any kind of breeze or fan-generated wind tends to keep them at bay. If you can find a place that’s exposed to wind, or you have a strong fan handy, both can prevent mosquitoes from biting you.

Long pants and shirtsleeves — especially tightly woven synthetic fabrics such as the types used in so-called athleisure garments — tend to keep mosquitoes off your skin. Repellents also work well, Day says. The CDC suggests looking for products that contain DEET, picaridin, IR3535, and oil of lemon eucalyptus, or p-menthane-3,8-diol (PMD). (6)  Apply these products to your ankles, wrists, forehead, elbows, and all the other knobby, bony places where the blood is up near the surface of the skin. Mosquitoes love to feast at these sites.

Also good to keep in mind: Mosquitoes are attracted to both the carbon dioxide humans exhale and the natural odors our bodies produce — stuff like sweat and foot odor. If you’ve been exercising, you’re likely to be both sweaty and producing higher amounts of carbon dioxide. Better to cool off and shower up indoors before heading outside. (7)

Follow all these precautions, and you can largely dodge mosquito bites all summer long.

Leave a comment

Your email address will not be published. Required fields are marked *