The reason for the bulging nipples of men is various, the specific analysis is as follows: 1, external stimulation, such as cold or shock caused by nipple bulge, belongs to the normal physiological reaction do not worry, remove the external stimulus can. 2, breast hyperplasia, men who take estrogen or endocrine disorders lead to breast hyperplasia, breast lumps, nipple swelling bulge. You need to go to a regular hospital for medication to regulate endocrine, or use estrogen under the guidance of a doctor. 3, nipple allergy, if the contact with poor quality clothing leads to nipple pain, swelling and itching. It is necessary to replace good quality clothes and use drugs for anti-allergy treatment. 4. Breast fibroids, benign tumors caused by endocrine disorders but with the possibility of malignant transformation, need to be detected early and diagnosed early and removed early to stop the possibility of cancer.