I am correcting you. Wash the entirety of your hands often!

Hi doctor here. I read this post a few times and I am not sure what you’re referring to by top and bottom part of your hand. I am guessing you mean your palm and the back of your hand.

Short answer: idk how fast bacteria move, but you are supposed to wash both the palm and the back of your hand. Most people are lazy and don’t take the time to do a proper thorough washing.

Am RN. Put a pea sized amount of dimethicone barrier cream on the back of your hands then rub the backs together. Completely fixes the dryness / protects from damage. It even builds up a barrier each time that will withstand a few washings without reapplication (important to only put in freshly cleaned skin so it doesn’t trap anything). Liquid gloves is one brand; when I’m at work I use whatever’s in stock (usually Medline). It’s more expensive than regular lotion but at the amount I use one bottle lasts several months. Dryness might cause skin cancer 50 years from now. It’s more likely that MRSA will get your arm rotted off in the next few months or you’ll catch a GI bug and shit yourself to death. Wash your hands.

It’s not that the bacteria “migrate” quickly over your skin. They probably will move about, but they are tiny and will move only slowly. However, humans’ hands are constantly touching and feeling about, our face, surfaces, clothing, and one another. So washing the entire hand is crucial.

Quite a lot of bacteria doesn’t move at all and even less can move on dry surfaces. You move them around by touching your face.

Washing your hands usually only damages your skin when you do it excessively. People working in the health sector often get problems there. If you are worried about skin damage, use hand cream when your skin gets too dry.

Bacteria or viruses enter either via wound, or mouth, eyes, lungs ect.

You wash your hands so they’re clean and you won’t eat bacteria from your hands when eating food

Well, the little buggers take a while to spread across a surface. They only move in terms of nanometers per second. Double to triple digits of nanometers per second, but still. They also tend to reproduce at a similar pace wherein even if they didn’t actively move themselves, the pressure from that would eventually cover a surface.

In other words, a few bacteria dropped on the back of hand can possibly end up having a colony on the palm of your hand in a few minutes.

However, since transferring from one surface to another is faster than that, well under a second, everything you touch is also going to have a colony soon after you touch it. Which isn’t necessarily bad since not all bacteria are pathogens to humans. But it very clearly shows why washing one’s hands thoroughly is a damn good idea.

So, even though the process can cause problems for hands, it’s still better than the problems of not washing thoroughly. Washing thoroughly includes both the palms and backs. If you’re washing often enough to cause skin problems, invest in good lotions and accept it as the price of not having pinkeye and diarrhea constantly.

People washing only the palms are going to eventually enjoy the pleasures of gastrointestinal upset and/or infected eyes, or respiratory infections. It might not be all the time, every time, but the chance of going through a year with poor hand washing in a medium to high risk environment without illness approaches zero. You might get lucky and it be nothing more than a cold, or something similarly easy to deal with.

But it might be MRSA.

Me? I’m playing the odds and following best practices.