Granny got this one wrong...

I have often noticed when I have cut a finger – like last week - a few days later I will get a cold/flu like illness (and boy does my wife suffer). Now I realise I have been making a mistake following my Granny’s advice:
“Let the air get to it”.
With an open wound, bacteria can enter through the broken skin and cause local or systemic infection.
1. Local infection
Bacteria (like Staphylococcus or Streptococcus) can infect the tissue directly around the wound.
Typical local signs include:
Redness
Swelling
Warmth
Throbbing
Pain or tenderness

2. Systemic effects
If the bacteria or their toxins spread beyond the wound, the body’s immune system mounts a broader response. This can lead to general malaise — a feeling of being unwell, tired, or achy — even if the infection seems small on the surface.
Common systemic signs include:
Fever or chills
Fatigue and weakness
Body aches
Loss of appetite
Elevated heart rate

3. Serious complications
If the infection spreads further into the bloodstream (sepsis), symptoms can worsen dramatically — including confusion, rapid breathing, or low blood pressure — and this requires emergency medical attention.
So bacteria can enter through an open wound and cause general malaise by triggering a localized infection or a systemic immune response. Keeping wounds clean, covered, and monitored for signs of infection is important.

What we used to be believe
People once thought that keeping a wound open to air would:
Help it “dry out” and form a scab
Prevent infection
Speed up healing

That made sense before we understood how cells actually repair skin.

What we know now:
Research shows that a moist (not wet), covered environment:
Speeds up healing: Skin cells migrate across moist tissue faster than dry scabs.
Reduces scarring: Less tissue death and more controlled healing – better cosmetic outcome.
Lowers infection risk: A clean dressing protects against bacteria and debris.
Decreases pain: Covered wounds tend to hurt less because nerves aren’t exposed to air.
When a wound “dries out,” a hard scab forms — but healing has to happen underneath that scab, which actually slows the process.
So, Granny was right most of the time - but the modern version of that old saying might be:
“Keep it clean, moist, and covered — not open to the air.”