Why aren't you supposed to scratch mosquito bites?

[terriko]

This summer has been unusually damp, and the mosquito population has bloomed as a result. I haven't worn mosquito repellent much since I was a teenager, preferring instead to rely on the "someone else will be tastier" defense, which has worked for years, but apparently is less effective when there are this many mosquitoes around.

For the first time in ages, I've got itchy mosquito bites. And as I was mastering the self-control necessary to keep from scratching, I started to wonder why I was doing this. So I turned to a friend and asked, "Why aren't you supposed to scratch mosquito bites?"

He replied, "Oh, because it makes them itch longer."

I looked at him. "But why does it make them itch longer?" And then, perhaps realising that I sounded like a 5 year old, i went on, "I mean, if they're injecting you with some itchy anti-coagulant, wouldn't it be absorbed by your body at the same rate regardless of how much you scratch?"

"I don't know. I know it does make them itch longer, because I've done it, but I never thought about why," he answered. "Darn, now it's going to bother me."

We guessed that one reason to avoid scratching is to avoid scars, but that didn't explain the fact that mosquito bites itch longer if you scratch them.

So I've done a bit of web research and verified it with friends and relatives with biology backgrounds (because I don't trust what I read on the internet), so here's the answer:

1. Scratching can produce scars
2. Scratching really does make mosquito bites itch longer!

Turns out that the anti-coagulant that mosquitoes inject (to keep your blood nice and thin and easy to suck) isn't itchy in and of itself -- it's actually that most of us are allergic to it. Your body produces histamines, which cause the itching. Unfortunately, scratching the mosquito bite also produces histamines, and more histamines means more itch.

While I was looking it up, I also found some suggested ways to make things less itchy. These ranged from baking soda paste to the (now obvious) anti-histamine drugs (same as you take for hayfever). But what's the number one way to deal with the itch? Distraction!

So... I recommend video games to treat mosquito bites. Now you know. ;)

Comments

[puzzlement]

I tend to find them most itchy between about 15 minutes and 60 minutes after the bite (with a second phase about a day later) and I tend to get bitten in environments where I can't access a video game that quickly. :)

I should carry antihistimines around anyway since I swell up massively in response to bee stings and we're not quite sure if or when the reaction will turn anaphylactic. However, since I don't get hayfever, I'm massively antihistimine naive and usually don't get mosquito bites in situations where it's acceptable to go off and sleep either!

Interesting discoveries. Did you stumble across the suggestions that people of type O blood attract more bites?

[terriko]

I've been getting an unusual number within the city, hence the slightly tongue-in-cheek recommendation (although, to be fair, it does work reasonably well because it keeps my hands busy and thus, not scratching). Seriously, though, any distraction will work.

While I was up at the lake, my mom pulled out an old bottle of something that claimed to be an anti-histamine cream. We expected it to have no effect, but it actually did help. Whether that was placebo or just 'cause it was nice cool distracting goop on my bitten toe, I have no idea. But that might be a more reasonable option than dosing your entire system with anti-histamines.

I hadn't heard that about type O potentially attracting more bites... but in looking it up, I found this article that claims that pregnancy also makes you a tastier target. Might be time to start investing in gauzy mosquito netting dresses for the summer. ;)

[puzzlement]

I don't know that there's any way in which I could be bitten more. My record is 40 in 10 minutes. (Unsurprisingly with that kind of exposure not being unusual, I also appear to be more allergic than most people: bigger lumps and so on.)

[beable]

Benadryl supposedly makes an anti-itch topical stick.

When I was a kid, my mom used to put calamine lotion on my bites. Supposedly it generally helps with itchiness.

[(Anonymous)]

"I found this article that claims that pregnancy also makes you a tastier target. Might be time to start investing in gauzy mosquito netting dresses for the summer. ;)"
... I'm sorry, am I missing something? Was there a causal relationship between those two sentences? :)

-Jay

PS: Stunningly, the captcha word for this post is "nonmacrobiotic". That's a 6-dollar dictionary word!

[terriko]

You don't know Mary, but I do, and she is both pregnant and type O, which is the relationship between the two.

Well, that and I found the information about both in one article. But that's why I thought Mary might be interested. :)

[terriko]

err, and she's in Australia, so it's not summer there yet, which is why the recommendation that she might need to be prepared.

[beable]

Given that I am not Type O, and I'm a tasy mosquito magnet, I'm skeptical.

[puzzlement]

I don't think it was suggested that Type O is either necessary or sufficient for it, just that there's a correlation. I'll see if I can dig up the cites later in the day.

Maybe it's infections

[(Anonymous)]

I thought the scrathing no-no was simply to prevent any infections. Scrathing might break the skin and cause small wounds.