herpes virus will remain dormant in nerve ganglia when a person gets chikenpox for the first time and skin manifestation of zooster with pains and malaise occurs when the immunity of the person reduces .sarcoidosis is an autoimmune disease where the exact cause of it is not known but bodys immune response is abnormal.For your chronic sarcoidosis are you taking any steroids is the main point here because if you are taking steroids that will reduce your immunity and zooster will reoccur.to prevent this you need to control your sarcoidosis with general measures like Eating a well-balanced diet with a variety of fresh fruits and vegetables,Drinking enough fluids every day,Getting six to eight hours of sleep each night,Exercising regularly and managing your weight,Quitting smoking.you consult your dr incase you are on steroids and explain your herpes then the dr can prescribe alternate medication.the same general measures will improve your immunity and herpes will not reoccur.