Are you sure it's a parasite? Could be chronic actinic dermatitis, which is a photo-allergy. People allergic to light (UV-A, UV-B, and visible light) often only have rashes on certain parts of their bodies, even parts not typically exposed to light. The head and neck are the most common places for it to begin.

I have this problem but no rash on my head or neck. I have spots on my back and arms and legs Began more than three years ago and multiple dermatologists and three biopsies confirm the diagnosis.

Just a shot in the dark. Nothing oozes from my rashes though.