<unk>  is thought to be caused by an altered ratio of estrogens to androgens mediated by an increase in estrogen production, a decrease in androgen production, or a combination of these two factors. Estrogen acts as a growth hormone to increase the size of male breast tissue. The cause of<unk>  is unknown in around 25% of cases. Drugs are estimated to cause 10–25% of cases of<unk> . Lavender and tea tree oils have estrogenic and anti-androgenic effects and there have been reports of their use causing prepubertal<unk> . Certain health problems in men such as liver disease, kidney failure, or low testosterone can cause breast growth in men. Drugs and liver disease are the most common cause in adults. Other medications known to cause<unk>  include methadone; aldosterone antagonists (spironolactone and eplerenone); HIV medication; cancer chemotherapy; hormone treatment for prostate cancer; heartburn and ulcer medications; calcium channel blockers; antifungal medications such as ketoconazole; antibiotics such as metronidazole; tricyclic antidepressants such as amitriptyline; and herbals such as lavender, tea tree oil, and dong quai. The insecticide phenothrin possesses antiandrogen activity and has been associated with<unk> . Physiologic<unk>  of a boy going through puberty. Both male and female newborns may show breast development at birth or in the first weeks of life. During pregnancy, the placenta converts the androgenic hormones dehydroepiandrosterone (DHEA) and DHEA sulfate to the estrogenic hormones estrone and estradiol, respectively; after these estrogens are produced by the placenta, they are transferred into the baby's circulation, thereby leading to temporary<unk>  in the baby. In some infants neonatal milk (also known as "witch's milk") can leak from the nipples. The temporary<unk>  seen in newborn babies usually resolves after two or three weeks. Hormonal changes of puberty leads to<unk>  in teen boys.<unk>  occurs in many boys during early puberty to middle puberty. It usually goes away within 6 months to 2 years.<unk>  in adolescents usually starts between the ages of 10 and 12 and commonly goes away after 18 months. Declining testosterone levels and an increase in the level of subcutaneous fatty tissue seen as part of the normal aging process can lead to<unk>  in older men. This is also known as senile<unk> . Increased fatty tissue in these men leads to increased conversion of androgenic hormones such as testosterone to estrogens. When the human body is deprived of adequate nutrition, testosterone levels drop, while the adrenal glands continue to produce estrogens, thereby causing a hormonal imbalance.<unk>  can also occur once normal nutrition is restarted (this is known as refeeding<unk> . Non-physiologic Medicines An exceptional case of extreme<unk>  in a 63-year-old man, treated with the nonsteroidal antiandrogen flutamide for prostate cancer. (a) With flutamide; (b) after discontinuation of flutamide. More than 90% of cases of<unk>  with nonsteroidal antiandrogens including flutamide are mild to moderate. About 10–25% of cases are estimated to result from the use of medications, known as nonphysiologic<unk> . Medications known to cause<unk>  include cimetidine, ketoconazole, gonadotropin-releasing hormone analogues, human growth hormone, human chorionic gonadotropin, 5α-reductase inhibitors such as finasteride and dutasteride, certain estrogens used for prostate cancer, and antiandrogens such as bicalutamide, flutamide, and spironolactone. Medications that are probably associated with<unk>  include calcium channel blockers such as verapamil, amlodipine, and nifedipine; risperidone, olanzapine, anabolic steroids, alcohol, opioids, efavirenz, alkylating agents, and omeprazole. Certain components of personal skin care products such as lavender essential oil or tea tree oil and certain dietary supplements such as dong quai and Tribulus terrestris have been associated with<unk> . Chronic disease People with kidney failure are often malnourished, which may contribute to<unk>  development. Dialysis may attenuate malnutrition of kidney failure. Additionally, many kidney failure patients experience a hormonal imbalance due to the suppression of testosterone production and testicular damage from high levels of urea also known as uremia-associated hypogonadism. In individuals with liver failure or cirrhosis, the liver's ability to properly metabolize hormones such as estrogen may be impaired. Additionally, those with alcoholic liver disease are further put at risk for development of<unk> ; ethanol may directly disrupt the synthesis of testosterone and the presence of phytoestrogens in alcoholic drinks may also contribute to a higher estrogen to testosterone ratio. Conditions that can cause malabsorption such as cystic fibrosis or ulcerative colitis may also produce<unk> . A small proportion of male<unk>  cases may be seen with rare inherited disorders such as spinal and bulbar muscular atrophy and the very rare aromatase excess syndrome. Tumors Testicular tumors such as Leydig cell tumors or Sertoli cell tumors (such as in Peutz–Jeghers syndrome) or hCG-secreting choriocarcinoma may result in<unk> . Other tumors such as adrenal tumors, pituitary gland tumors (such as a prolactinoma), or lung cancer, can produce hormones that alter the male–female hormone balance and cause<unk> . Individuals with prostate cancer who are treated with androgen deprivation therapy may experience<unk> .
Gynecomastia
Breast atrophy
Pattern hair loss
Post-vacation blues
Adipomastia
Trichomegaly
Breast hypertrophy
Clitoromegaly