Just so that I wouldn't hijack anyones posts thought I would update
Son is now on prescriptive treatement for his acne, endocrinologist did not appear to think that it was steroid induced(although it did appear when he started taking them) Have decided not to give up on his height yet (would love to prove endo wrong 
so have decided to up his nutritional status )
Obviously with this disease the body appears to be deprived of so many essential nutrients/vitamins (like the B's, D etc) so have decided to be pro-active.
As well as the pentasa, azathioprine and celtirizine(anti-histamine) he is now also taking.........wait for it....... calcium, magnesium,D3,selenium, zinc, chromium, vits C, B and E and the good old pro-biotics(at the moment on 5 billion a day) which results in much hilarity at meal time regarding if they are re-producing and at what rate(and some comments that cannot be repeated on here 
)
I hasten to add they are not all individual tables (some are combined)
Waste of money/time. I don't know but my thinking is that with this disease as the body does appear to be deficient(otherwise why vit d and B12 shots given by medical people) anything extra has to be a bonus(bloods not currently showing deficiency though) have got a phase 2 plan at the ready lol, don't know how much (if any) good it will do but prepared to give it a go(son also obliging-and no not under duress, honest)