Some people have a natural immunity to aura parasites and other attacks. Some have taught themselves to work on their aura (i.e. Astral Al). For the rest of us, the various harmonics and interactions with other auras, etheric beings, thought forms and casual curses directed towards you creates ripples and distortions in our auras. Even the geomancy of the room you just walked through has its effect. Because we are "all" in the same boat, we do not notice what's happening to us. Only occasionally are we awakened when we meet someone with a "complete aura".
Beware, if you curse, your aura is weak in that area and you are more susceptible to those problems. If you gossip, you are weakening your resistance to the harm you are producing.
As an example, move your cursor over the image to see the effects of a consciously directed attack.
The aura is effected by what is outside the body, what is happening in the body (flu infection), what the mind is thinking and what words (remember - they are LAW and try to manifest) you speak and are spoken to you.
To see an illustration of what can happen to the aura, click here.