Yes, I'm highly defensive, too. And like you, I can't hide it....once someone hurts me/insults me....anger seeps out of my pores. There will be no controlling it. And once you hurt me, all bets are off...I will have no problem giving in right back to you in a more concentrated form. I may have said this to you before...but it sounds like you may just be a highly sensitive person. If you google 'highly sensitive person' you will see we are not alone. And while, like you, I thought that me being hypersensitive to criticism was from a lifetime filled with neglect and criticism, it is believed that it is a inherited trait.
There are good and bad things to being highly sensitive. The good include: we have wonderful imaginations, we are curious, we are creative and intuitive. You already know what the bad includes.
Pulitzer Prize winner Pearl S Buck once wrote:
"The truly creative mind in any field is no more than this:
A human creature born abnormally, inhumanly sensitive.
To him... a touch is a blow,
a sound is a noise,
a misfortune is a tragedy,
a joy is an ecstasy,
a friend is a lover,
a lover is a god,
and failure is death.
Having the innate trait of high psychological sensitivity is often confused with social anxiety. In fact, I often wonder whether I truly have social anxiety or if my being highly sensitive does not allow me to function in a socially 'normal" way. I'm going with the latter.