French again

Hi my lovely helpful linguaphiles, I've some simple french questions again.

What's the meaning of "de" here? J'ai de la fievre.

Also, what are these?

J'ai mal au nez.
J'ai mal a la main/vente/gorge/tete
J'ai mal aux dents/yeux

It's all to do with illness. If it's possible, could you please translate to english word by word so that i can get the idea when i use them?

Gazillion of thanks in advance! :)