Bruising Easily When the Blood Tests Are Normal

"I don't remember hitting anything, but bruises keep showing up on my arms."

People who say this usually arrive carrying a worry. Is something wrong with the blood, is this a sign of something serious. So they have the blood tested, and they are told it is normal. Then the frustration grows. The bruises keep coming, and nothing is wrong.

Let me follow this common thing through today.

The bruises appear in particular places

Start with where they appear.

There is a study of 193 older adults in Korea. Fifty-seven of them had bruising, and in 96.5% of those it was on the lower arms and the backs of the hands. Calves and feet came next, then thighs. The average age when it began was around 71.

They do not appear just anywhere. They appear where the skin is thin and there is little underneath to hold things up.

What tore is a vessel, but what loosened is what surrounds it

This is the point of today.

The fine vessels in the skin are not standing alone. In the layer called the dermis, collagen and elastin are woven like a net, and the vessels sit held inside that net. Deeper veins are wrapped in firm fascia. But the capillaries near the surface of the skin lean on this loose net alone.

With age the net thins and opens up. Two things then happen together. Vessels tear under smaller forces, and the blood that leaks out has nothing to stop it from spreading, so it spreads wide. That is why the same bump that left no mark when you were younger now leaves a palm-sized patch.

I put it this way in the clinic: the tent poles did not break — the canvas stretched.

What happens on the inner surface of a vessel is a separate story. (The inner surface of a vessel feels the flow)

So the tests come back normal

Clotting function and platelet counts have no direct part in this. So they usually come back normal.

The textbooks say so too. In this kind of bruising, coagulation studies and blood counts are typically normal, and testing is widened only when other unusual bleeding is present.

A normal test does not mean "nothing is happening." It means "nothing is wrong on the blood side." The trouble was not in the blood but in the place that was holding it.

What the body is doing while the color changes

"It has been almost a month and it still hasn't gone." I hear this often as well.

You have seen a bruise go from dark red to bluish, then greenish, then fade to yellow. The order of those colors is there because the body is clearing the leaked blood in a set order.

When red cells outside the vessel break down, the red pigment inside them is left. The cells that handle the clearing break it down, first into a green substance, then into a yellow one. That yellow substance is bilirubin — the same one that colors the whites of the eyes in jaundice. (Why I look at the eyes in the clinic)

So when a bruise changes color it is not getting worse — it is being cleared away. That clearing has to be carried off by blood and lymph to finish. Where circulation is slower, the same bruise fades more slowly. That is also why a bruise on the shin lingers longer than one on the forearm.

The sun explanation, and then

Bruising like this is usually explained by long sun exposure. Many sources say ultraviolet light wears down the net in the dermis.

Yet in the Korean study above, no clear relation appeared between the amount of sun exposure and the bruising. Four other things did: dyslipidemia, anticoagulants (blood-thinning medication), a history of skin disease, and lack of exercise.

Three of the four are matters outside the skin. How strong the net in the skin is does not get decided by the skin alone.

I look past the bruise to the thinning mesh

I do not start by looking for a way to remove the bruises. I look at the conditions under which the net grew thin.

Collagen does not stay as it was once woven. It is taken down and rebuilt, a little at a time. Certain enzymes do the taking down, and proteins that inhibit those enzymes sit alongside them to keep a balance. How strong a net remains is set by the ratio between the two. Long-standing inflammation and ultraviolet light favor the side that takes down.

Steroids suppress the proliferation of the cells that make collagen. Applied over a long time they thin the dermis, which shows up as visible fine vessels or as this kind of bruising. If you have been using an ointment for years, it is worth raising once. It is medication taken because it is needed, so it is not something to stop on your own — please discuss it with whoever prescribed it.

So I ask together whether there is an anticoagulant among the medications, whether there is a long-used ointment, how the blood sugar and lipids look, and how much the body is being used. I read the lack of exercise in that study along the same grain. Tissue that is not used gets lazy about rebuilding as well.

Herbal medicine here is not used to harden vessels. The body is what reweaves the net of the dermis. I look at what could be slowing that work: whether inflammation that has not settled remains, whether blood reaches the area, whether protein is actually being absorbed.

That said, tissue that thinned over decades does not thicken in a few weeks. This work does not move at that speed.

When to have it checked first

If bruises suddenly increase sharply, if nosebleeds or bleeding gums come with them, or if pinpoint red dots appear on the legs, that is when the blood side should be checked. The same is true if bruising increases sharply while you are taking an anticoagulant.

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Bruises that appear without a bump often come not from blood getting thinner, but from what surrounded the blood growing thin.

If you were told the tests were normal and went home, that statement is half right. The blood is normal. It is the place that blood passes through that is not what it was.

Sources

• With age the dermal connective tissue thins and cannot support the microvasculature, so minor force causes leakage — coagulation studies and platelet counts are typically normal — StatPearls
• A survey of 193 older Korean adults — 96.5% on the lower arms and hands; dyslipidemia, anticoagulants, skin disease history and lack of exercise were associated, while sun exposure was not — Annals of Dermatology, 2021
• Glucocorticoids inhibit fibroblast proliferation and collagen synthesis, thinning the dermis and presenting as telangiectasia or purpura — Clinical, Cosmetic and Investigational Dermatology, 2020

Written by Dr. Heo Ji-young (Ph.D. in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)