🚀 go-pugleaf

bara...@comcast.net wrote:
> The redness and whiteness during light burns is the result of different
> behaviour of the subcutaneous capillaries.

No. Redness and PALENESS is the result of the different behavior of
capillaries

There is a different between paleness and whiteness.

> Heat induces shock.
>
> The resident granulocytes (histiocytes residing in the subcutaneous tissue)
> degranulate, and among others release histamine that is a potent
> vasoconstrictor. It causes the smooth muscle in the capillary to constrict.
> Constricted blood vessels reduce the blood flow locally, and the skin looks
> pale (white).

>This reaction is less visible in the more pigmented skin.

Not in my case. I am very dark-skinned [literally as dark as an oreo
cookie]. My burn wound appeared white -- foamy white. It was NOT cold,
so vasocontriction didn't cause the color change. The wound was
unusually hot, extremely irritating and painful and FOAMY WHITE. It
looked very frightening.

What caused this whiteness? I know it is NOT vasoconstriction! It
seemed like a first-degree burn. The skin texture and moisture content
didn't change much. There was NO _swelling_ at all!

Is it the coagulation of the epidermal proteins?

I hope my response didn't seem harsh. I was just trying to clarify that
the WHITENESS I am describing has nothing to do with VASOCONSTRICTION.

Unlike what you describe, the WHITENESS did NOT turn red at all. The
wound began to darken to my normal skin color after it healed.

If a black person wants to be white, [s]he could easily become white by
inflicting a first-degree thermal burn on him[her]self! LOL

> Now if the burn is more severe, is causes tissue damage. Cells necrotize and
> the permeability of endothelial lining of the blood vessels increases
> (serum exudes)  in addition to the histamines other components are released
> too including the components of the complement system, all of this results
> in a localized, but rapidly escalating inflammatory reaction. This further
> increases the vascular permeability, vasodilation and enhanced blood  which
> is necessary for leucocytes to infiltrate the damaged tissue (to protect and
> help to repair it).
>
> At this stage erythema formation is common occurrence which is the swelling
> and redness of the affected areas of the skin. This takes some time to
> develop, so the proper order of changes is: whiteness immediately after the
> injury, followed by redness in minutes or hours.
>
> Now if you have a VERY strong burn, "cauterizing" burn, that coagulates
> proteins even deeper in the tissue, it plugs the blood vessels by causing
> the proteins to coagulate, there is no blood circulation, and the skin
> remains pale (white). Because of reduced circulation, it takes much longer
> for the inflammatory reaction to begin and usually the injury develops a
> decently sized "sack" filled with yellowish plasma that hides any color
> below it (plain optical phenomenon) it  protects the underlying tissue but
> dries up gradually and normal blood coagulation proteins help to form a
> brownish cover over the damaged area.
>
> The ultimate burn injury results in charring. Charred tissue is initially a
> dry mixture of skin proteins and blood, contains large amount of
> carbohydrates, lipids, hemoglobins etc, and all kind of degradation products
> thereof, carbonized,  caramelized sugars etc, that causes it to have a dark
> almost black color. It never regenerates (dead tissue), but easily breaks
> and allows bacteria to seep into the wounds. charred tissue is usually
> removed to hasten the healing.
> 
> lajos