Trucal acne may be due to dandruff. There is also a condition called acne conglobata. Where u get large scarring acne on back. Sensitivity to male hormones is the main cause. Oily food and high protein diet are the main causes that increase acne. You will need to be put on oral isotretinoin for a long time. It will subside in about 3 to 4 months of treatment. Please consult a dermatologist near you for more details. Scar creams are also available once your acne start subsiding. If you have dandruff u can use a ketoconazole containing shampoos to clear it off and see if helps your acne. Warm regards. Dr. Rajdeep Mysore. Chirag Hospital Bangalore