Is your wound infected, or is it just healing?

Your wound is supposed to be inflamed

Everyone is taught the same three warning signs: redness, warmth, tenderness. The problem is that two of them are meant to be present.

Warmth and tenderness are phase one of healing. They are not a complication - they are the mechanism. As surgeons we depend on that inflammatory response; a wound that mounts none of it does not knit together.

Which means neither sign, on its own, tells you anything.

A trained eye is not looking for inflammation. It is looking for more inflammation than the wound explains - and then for which direction it is moving.

The test you can actually do

This is the single most useful thing in this article, and it requires a pen.

Trace the edge of the redness tonight. Draw a line on the skin at the border. Look again tomorrow.

A thin border of pink around a fresh incision is normal. Redness that is spreading, out of proportion to the wound, and not retreating over a day is a different matter. The pen turns a subjective judgement into an objective one, and it works whether or not you have any medical knowledge.

Call the same day if

None of these is a "see how it goes overnight" symptom.

The one whisper worth knowing about

Everything above concerns infection above the deep fascia, where it can be seen. Below that layer, an infection has no easy route to the skin - so it produces little pain, little redness, and surfaces late.

Its early tell is fluid out of proportion. Not pus, necessarily. Plain serous fluid, in a volume the wound has no obvious reason to produce.

That disproportion is inflammation walled around a collection that has not found an exit. It is subtle, it is easy to dismiss, and it is worth mentioning at a follow-up appointment even when nothing else seems wrong.

Whitish fluid is a different question

Cloudy white fluid almost always means pus.

It can also be fat necrosis that has liquefied, and at the bedside the two are genuinely hard to tell apart. Neither is reassuring - dead fat is food for bacteria too. And if the fat beneath the skin has died, the skin above it can follow.

This is one to show someone rather than photograph and worry about.

The honest limit of an article like this

You will probably not catch the deep one from reading this. That is not a failure of the article; it is the nature of the problem. Infections that declare themselves are the ones you can act on, and the pen test handles those well. The quiet ones are what follow-up appointments exist for.

Which is the real answer to "should I bother going to my follow-up when I feel fine": yes, because feeling fine is compatible with the specific problem that is hardest to see.

If you are in the first weeks after an operation, this sits alongside the other two things that alarm people and usually should not - swelling that peaks on day three and bruising that travels downward.

Warmth and tenderness are the mechanism. Direction is the signal.