There can be various causes of gynecomastia. Some of which are:
1. Hormonal changes: If the level of testosterone is less than oestrogen in men, it can cause gynecomastia.
2. Prescription medicines: Many types of medicines can cause a hormonal imbalance and, thus, result in gynecomastia. These medicines include anti-anxiety medicines, anabolic steroids, anti-androgen medicines, antibiotics, heart medicine, etc.
3. Health conditions: Gynecomastia can manifest due to underlying health conditions like hyperthyroidism, hypogonadism, liver cirrhosis, kidney failure, malnutrition, etc.

In most cases, gynecomastia gets resolved on its own, i.e., without medical intervention. Depending on the condition, gynecomastia treatment can be approached in two ways:

1. Non-surgical: This approach is generally used when gynecomastia is caused by prescription medicines or underlying health conditions. In which case, the doctor may modify the prescription or treat the causative health condition.

Another non-surgical approach for gynecomastia involves the use of breast cancer medicines.

2. Surgical: Depending on the condition, gynecomastia can be resolved through surgical procedures like liposuction or mastectomy. In liposuction, breast fat is removed through surgery. In mastectomy, the glandular tissue is removed. The doctor may also advise a combination of the two procedures.

To begin with, you can consult an endocrinologist. They can help you find the root cause of your condition. If you want to opt for gynecomastia surgery, you should consult a plastic surgeon.

Gynecomastia can be diagnosed based on symptoms, medical history and examination of the breast tissue and genitals. To find the root cause of the condition, the doctor may recommend diagnostic tests like blood tests, mammograms, CT scans, MRI scans, testicular ultrasounds, and tissue biopsies.

No. Since gynecomastia is caused by hormonal imbalance, in most cases, it is not possible to prevent gynecomastia. Nonetheless, early diagnosis of gynecomastia may help prevent the worsening of condition through various non-surgical approaches.