Gynecomastia (guy-nuh-koh-MAS-tee-uh) is an increase in the amount of breast gland tissue in boys or men, caused by an imbalance of the hormones estrogen and testosterone. Gynecomastia can affect one or both breasts, sometimes unevenly.
Newborns, boys going through puberty and older men may develop gynecomastia as a result of normal changes in hormone levels, though other causes also exist.
Generally, gynecomastia isn't a serious problem, but it can be tough to cope with the condition. Men and boys with gynecomastia sometimes have pain in their breasts and may feel embarrassed.
Gynecomastia may go away on its own. If it persists, medication or surgery may help.
Signs and symptoms of gynecomastia include:
- Swollen breast tissue
- Breast tenderness
When to see a doctor
See your doctor if you have:
- Pain or tenderness
- Nipple discharge in one or both breasts
Gynecomastia is triggered by a decrease in the amount of the hormone testosterone compared with estrogen. The decrease can be caused by conditions that block the effects of testosterone, reduce testosterone or increase your estrogen level.
Several things can upset the hormone balance, including the following.
Natural hormone changes
The hormones testosterone and estrogen control sex characteristics in both men and women. Testosterone controls male traits, such as muscle mass and body hair. Estrogen controls female traits, including the growth of breasts.
Most people think of estrogen as an exclusively female hormone, but men also produce it — though normally in small quantities. Male estrogen levels that are too high or are out of balance with testosterone levels can cause gynecomastia.
- Gynecomastia in infants. More than half of male infants are born with enlarged breasts due to the effects of their mother's estrogen. Generally, the swollen breast tissue goes away within two to three weeks after birth.
- Gynecomastia during puberty. Gynecomastia caused by hormone changes during puberty is relatively common. In most cases, the swollen breast tissue will go away without treatment within six months to two years.
- Gynecomastia in adults. The prevalence of gynecomastia peaks again between the ages of 50 and 69. At least 1 in 4 men in this age group is affected.
A number of medications can cause gynecomastia. These include:
- Anti-androgens used to treat an enlarged prostate, prostate cancer and other conditions. Examples include flutamide, finasteride (Proscar, Propecia) and spironolactone (Aldactone, Carospir).
- Anabolic steroids and androgens, which are prescribed by doctors for certain conditions or are sometimes used illegally by athletes to build muscle and enhance performance.
- AIDS medications. Gynecomastia can develop in men who are HIV-positive and receiving a treatment regimen called highly active antiretroviral therapy. Efavirenz (Sustiva) is more commonly associated with gynecomastia than are other HIV medications.
- Anti-anxiety medications, such as diazepam (Valium).
- Tricyclic antidepressants.
- Ulcer medications, such as the over-the-counter drug cimetidine (Tagamet HB).
- Cancer treatment.
- Heart medications, such as digoxin (Lanoxin) and calcium channel blockers.
- Stomach-emptying medications, such as metoclopramide (Reglan).
Street drugs and alcohol
Substances that can cause gynecomastia include:
- Amphetamines, used to treat attention-deficit/hyperactivity disorder
- Methadone (Methadose, Dolophine)
Several health conditions can cause gynecomastia by affecting the normal balance of hormones. These include:
- Hypogonadism. Conditions that interfere with normal testosterone production, such as Klinefelter syndrome or pituitary insufficiency, can be associated with gynecomastia.
- Aging. Hormone changes that occur with normal aging can cause gynecomastia, especially in men who are overweight.
- Tumors. Some tumors, such as those involving the testes, adrenal glands or pituitary gland, can produce hormones that alter the male-female hormone balance.
- Hyperthyroidism. In this condition, the thyroid gland produces too much of the hormone thyroxine.
- Kidney failure. About half the people being treated with dialysis experience gynecomastia due to hormonal changes.
- Liver failure and cirrhosis. Changes in hormone levels related to liver problems and cirrhosis medications are associated with gynecomastia.
- Malnutrition and starvation. When your body is deprived of adequate nutrition, testosterone levels drop while estrogen levels remain the same, causing a hormonal imbalance. Gynecomastia can also happen when normal nutrition resumes.
Plant oils, such as tea tree or lavender, used in shampoos, soaps or lotions have been associated with gynecomastia. This is probably due to their weak estrogenic activity.
Risk factors for gynecomastia include:
- Older age
- Use of anabolic steroids or androgens to enhance athletic performance
- Certain health conditions, including liver and kidney disease, thyroid disease, hormonally active tumors, and Klinefelter syndrome
Gynecomastia has few physical complications, but it can cause psychological or emotional problems caused by appearance.
There are a few factors you can control that may reduce the risk of gynecomastia:
- Don't use drugs. Examples include steroids and androgens, amphetamines, heroin, and marijuana.
- Avoid alcohol. Don't drink alcohol. If you do drink, do so in moderation.
- Review your medications. If you're taking medication known to cause gynecomastia, ask your doctor if there are other choices.