Causes

Gynaecomastia is due to enlargement of the small bud of breast tissue  under the nipple.

It is due to an imbalance between oestrogen and testosterone levels in the blood.

This occurs quite frequently at puberty.

Drugs - a number of common medicines have gynaecomastia as a possible side effect. These are listed below.

• Digoxin (Lanoxin)
• Spironolactone (Aldactone)
• Cimetidine (Tagamet)
• Ketoconazole (Nizoral)
• Finasteride (Proscar)
• Dutasteride (Avodart)
• Phenothiazines
• Methyldopa
• Isoniazid
• Phenytoin
• Imiprimine
• Steroids
• Marijuana
• Herbal remedies containing phyto-oestrogens
• Gynaecomastia can also occur with a number of diseases that are listed here.
• Liver disease
• Prostate cancer treatment orchidectomy, anti-androgen drugs, Goserelin, or administration of oestrogen.
• Testicular cancer
• Hyperthyroidism
• During recovery from malnutrition
• Klinefelters syndrome genetic abnormality with extra X chromosome
• Testicular failure