I think I'm finally getting to grips with OCD scratching in mice, helped by the fact that I've caught it myself. This story actually goes back a few months but the doctor has had as much fun trying to diagnose me as vets have had diagnosing mice.
Mowbli came to live with me in April and I've mentioned that he succumbed to the dreaded OCD scratching some time after that. I haven't made a note of the dates but a short while after he started scratching, I started getting itchy patches too which looked to me like ringworm and I mentioned that to the doctor but the first doctor I saw discounted that idea and gave me some steroid/antibiotic cream. I asked about a skin scrape and was told that skin scrapes weren't performed at the surgery. When several weeks of that treatment only resulted in it getting worse I went back and saw a different doctor who thankfully did agree to a skin scrape and changed my medication to a fungal cream instead (even though she thought I had discoid eczema). Anyway to cut a long story short, the fungal cream did start to work and today I have finally got the results of the skin scrape "Trichophyton Mentagrophyhtes" which is a fungal/ringworm infection.
I have no proof that I caught it from Mowbli of course. I could quite easily have caught it from the animals I work with and although I have told my vet about it, he hasn't done any tests on Mowbli. The good news is that both Mowbli and I have responded well to treatment with a fungal cream and I have also discovered an online article which mentions that the presence of mites, abrading the skin of the mouse might provide a more favourable environment for the ringworm infection. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2134665/?page=1
So although it may not be the single cause of OCD scratching in mice, I am inclined to suggest tackling OCD scratching with mite treatment and a fungal treatment too (PLEASE NOTE I AM NOT A VET AND THIS IS JUST A PERSONAL OBSERVATION).