This is a pretty far out question, but...Has he spent any time in central America/Northern So. America?
If so, there is a tiny (nearly microscopic spider that infests the epidermus that causes extreme itching and is unfamiliar to US docs unles they have spent some time studying tropical diseases. Had a friend who got it in So. Mexico about 30 years ago. They literally locked her up as insane until a doc who had been in the tropics diagnosed it.
I appreciate your input. The company he works for sells product to places like Nigeria, so I suppose it's not out of the question.