Hi doctor, is it safe to use a medicated barrier cream like sudocrem or desitin for prolonged lengths of time?

Yes: We've been using Desitin on baby's butts for decades without any untoward effects, and their skin is much thinner and more sensitive than adult skin. However, I wouldn't say the same for creams or ointments that have antimicrobials in them, as long term use of these may predispose to skin infections with resistant bacteria.

Try this: Agree with Dr. Maes's answer. However there is a very reliable, old fashioned diaper rash treatment, even used on my own children. Whisk raw egg white with small amount of alcohol (Cheap brandy, whisky, vodka etc.) Apply to area with soft pastry brush. Allow alcohol to evaporate leaving thin protective layer of dried egg white. Works well and very effective. Try it. You will like it.