Long days and short nights. Beaches, lakes and pools. Campfires and cookouts. Playgrounds and sprinklers. A visit to the museum any day of the week.
Is there a downside to summer? We can only think of one – bug bites. Even if you use every type of insect repellent, those annoying mosquitoes seem to find a way to our sweet skin, take a drink of blood and leave us with an itchy, itchy red bump. So why do bug bites itch so much? We answer this question with help from Hank Green at the SciShow.
Warning: While reading this blog, you might feel a little squeamish. You might want to scratch an existing bug bite. And in some cases you might call out, “Yuck!”
Let’s start at the beginning. You’re outside enjoying a summer activity when you realize there is a spot on your skin that is very itchy! You look down and there is a small red bump.
This is the result of a mosquito using its proboscis to stick your skin and drink some of your blood.
The proboscis, a long, straw-like tube, is made up of other long, bendable extremities. After the initial puncture into your skin, the mandibles and maxillae stretch the tiny hole wide enough to make room for the labrum and the hypopharynx. The labrum then sucks your blood while the hypopharynx injects saliva back into your skin. Because the mosquito’s saliva is an anticoagulant, it prevents your blood from clotting around the opening and allows that pesky bug to keep drinking until you swat it off or scare it away.
You can thank this saliva for what happens next, because chances are you’re allergic to it.
The allergy causes your body to produce histamine, a protein that causes inflammation and widens your capillaries so that white blood cells can attack the allergen.
For a reason that scientists don’t yet understand, histamine makes us itch. If you have seasonal allergies, you know exactly what we’re talking about. Your body’s production of histamine in response to a pollen allergy is what makes you want to rub your eyes and nose.
So it’s not the actual bug bite that makes you want to scratch, scratch, scratch! It’s the histamine.