I suffered from this for well over twenty years and didn't even realise.
I only gradually came to the realisation that I do not have parasites living on my skin in the last 18 months, or so.
It started in '86 or '87 when two work colleagues told me that they thought that I may have head-lice. I didn't have head-lice, I have never had head-lice, they were mistaken.
Unfortunately the psychological damage was done. Resulting in me being utterly convinced, that, no matter what various doctor's & specialists told me to the contrary, I had head-lice.
This caused me many problems over the years, chief amongst them, relatioships, or my refusal to take-up any of the offers of either; sex, dates or similar ( except on rare occasions where I was drunk with an unfamiliar woman ), for fear of passing-on my "infestation".
Needless to say that I found this to be super-depressing & the fact that I kept it all to myself from the age of 16/17 to 40, has really damaged me further, I feel.
It has been a horrible ordeal. Just venting, sorry.
Am I alone in suffering from this kind of delusion?