I agree with your sentiments about Antibiotics causing sebderm. I had surgery years ago and was given Antibiotics and then later on I happened to show symptoms which led to my Seborrheic Dermatitis . If your healthy gut flora has been destroyed by Antibiotics I highly recommend you kill off the bad yeasts with antifungals i.e coconut oil, pau'darco, oil of oregano etc. and then start taking a probiotic supplement or making your own kefir, sauerkraut or kimchi.