A word or two about applying heat to treat inflammation or infections of body parts. Based on absolutely no current research other than what I've learned and observed, this is my take on it. The reason I mention it: I'm applying a little heat to the area of me which is most in contact with my bicycle saddle. Let's keep that between you and me.
Why is heat useful? Because it increases circulation to the area in question: capillaries dilate, blood flows in, which is good in two ways. It carries with it the body's own defenses (ie, white blood cells of various types), and, assuming you might be on antibiotics, it brings more of that, too.
Why "moist" heat? Nothing magic about moisture, per se. It doesn't get below a couple of cell layers, after all. It's about conforming to the part you're trying to heat: a moist cloth will lay entirely against the skin, whereas a heating pad has gaps in its contact.
What's a Koch-Mason dressing? Wow, where did you hear of that? I can't even find it on Google. It's an old-style multi-layer dressing intended to apply continuous heat: on the skin, a warm moist cloth of some sort; then plastic wrap; then some variety of heating pad; then a dry towel above that. In the olden days, we used them, in the hospital, for some people with cellulitis. You need to be careful about the heating pad. The hospital kinds use warm water circulating in the pad. Electric ones pose hazards, both from the electricity and from over-heating.
What's your secret, Sid? Well, you asked, so here it is. If you want to apply constant heat to an extremity, and don't want to be tied down by an electric cord (most assuredly, this is not a fetish blog) do this: cover the area with a nice warm moist cloth, then wrap with plastic wrap, then follow with a dry towel, and tape it all in place. The insulation will keep the heat in, and you can be up and around. The area will be significantly warmer than the rest of you. Because of the moisture, it's good to remove the whole thing every few hours to prevent dishpan hands of the leg, or whatever.
There's always a catch: applying heat to an extremity that has circulatory compromise can be dangerous. Even if you have a minor booboo, don't be using heat when there are vascular problems without having your doctor in the loop.
