Blood phobia also known as homophobia. Blood phobia or the fear of blood comes from the look of blood. Essentially seeping blood, moving blood or the quantities of blood tend to be a trigger for those people who have blood phobia.
This is normally created by sensitizing events in childhood. Where a child may fall over or cut themselves. And then sight of blood caused an extreme anxiety reaction and that is the initial cause of blood phobia.
Blood phobia is a particularly dangerous and tricky fear. In the sense that fear itself can lead to avoidance which is true for most phobias.
The problem though is if someone has a fear of blood and it is their own blood. They might avoid going to places like hospitals. Because there is a perception that in a place like a hospital, they could witness more blood. Which is the key thing they are looking to avoid.