You've probably heard your mother or grandmother complain about hot flashes. You may have even watched them suddenly break out in a drenching sweat and fan themselves vigorously on a cool day. Most young women don't give it a second thought, filing it away as something that just happens to older women. So, when a hot flash first happens to you, it can be rather frightening -- especially if you are relatively young. While loss of normal ovarian function is one of the most common causes of hot flashes, similar symptoms can develop with use of certain medications, alcohol consumption, as well as medical conditions such as endocrine disorders, cancer and cancer treatments, and rare tumors.
Hot Flashes Explained
The physiological processes that lead to hot flashes are complicated and not completely understood. Your body temperature is tightly regulated and coordinated by a structure in your brain called the hypothalamus. Many factors influence this regulatory center, including various hormones and neurotransmitters. A hot flash basically represents an exaggerated response to a slight increase in body temperature, and this overreaction leads to flushing and sweating.
Perimenopause and Early Menopause
Women normally experience menopause -- defined as the absence of menstruation for 12 consecutive months -- between age 45 and 55. It occurs because the number of immature eggs in your ovaries, called ovarian follicles, are depleted to a critically low level. Menopause is preceded by a transitional period called perimenopause, which lasts about 4 years, on average. If you're still menstruating and experience occasional hot flashes, you might have entered your perimenopausal years. Alternatively, if you're aged 40 to 45 and your periods have stopped, you may be experiencing early menopause with typical menopausal symptoms.
Just as with menopause later in life, early menopause involves a gradual decline in ovarian function with an accompanying decrease in estrogen production. Declining estrogen levels during perimenopause and early menopause are key to hot flashes during these times of a woman's life. You are at risk for early menopause if there is a history of it in your family. Active cigarette smoking has also been shown to increase your risk.
Premature menopause describes the permanent cessation of menstruation before age 40, a condition that affects approximately 1 percent of women. It is commonly caused by primary ovarian insufficiency (POI), characterized by depletion or abnormal functioning of the ovarian follicles. Women with POI often experience hot flashes and other symptoms associated with low estrogen levels before and they stop having periods -- sometimes as early as their late teens or early 20s. Most cases of POI occur spontaneously without an identifiable cause. But the condition may develop in association with certain genetic disorders, autoimmune diseases in which the immune system attacks the ovaries, and even some infections, such as mumps.
Premature menopause can also be induced by medical or surgical interventions. For example, exposure to chemotherapeutic drugs or radiation therapy used for cancer treatment can temporarily or permanently damage the ovaries. Surgical menopause refers to cessation of menstruation due to removal of both ovaries. Additionally, some women loose ovarian function after a simple hysterectomy -- removal of the uterus but not the ovaries. Tumors or conditions affecting hypothalamus or pituitary gland of the brain can also cause premature menopause due to impaired secretion of hormones that normally regulate ovarian function.
Alcohol, Supplements and Medications
Alcohol, and certain supplements and medications can cause skin flushing and a sensation of heat, with or without sweating. These flushing episodes can be easily confused with hot flashes in young women, but are different as they are unrelated to declining ovarian function. Alcohol -- particularly beer, sherry, and some red and dessert wines -- might cause flushing due to high histamine content, a substance that dilates blood vessels. An inherited enzyme deficiency, common among people of Asian heritage, is another common cause of alcohol-induced flushing reactions due to impaired alcohol metabolism.
The supplement niacin is another common cause of flushing, especially when taken in high doses. The supplement provokes increased production of immune system chemicals called prostaglandins, which trigger blood vessel dilation. A variety of medications can also cause flushing reactions, either through blood vessel dilation or other complex mechanisms. A few common examples include: -- opioid pain medicines, such as oxycodone (Oxycontin) and meperidine (Demerol) -- calcium channel blockers for high blood pressure and heart disorders, such as amlodipine (Norvasc) and nifedipine (Procardia)
Non-Reproductive Hormonal Disorders
Sweating or flushing is a central feature of several endocrine disorders that produce an excess of different hormones. Hyperthyroidism and pheochromocytoma are examples of such conditions. In hyperthyroidism, the thyroid gland in overactive and produces too much thyroid hormone which causes an increase in your body's metabolism leading to sweating and difficulty handling heat. Pheochromocytoma is a rare tumor of the adrenal gland, a small gland located on top of each kidney. This tumor secretes the catecholamine hormones epinephrine and norepinephrine. These hormones can affect the hypothalamus, the thermoregulatory center in the brain causing hot flashes. Other symptoms experienced with these conditions include a rapid heart rate, anxiety, and tremors and elevated blood pressure (ref 8).
Cancer and Cancer Treatment
Hot flashes and nigh sweats can also be a side effect of several types of cancer or cancer treatment. For instance, medications like tamoxifen used to treat breast cancer lower estrogen levels, which in turn can affect the thermoregulatory center in the brain. Certain chemotherapeutic drugs can also trigger early menopause (ref 8). Flushing of the face and heat sensations are the most common symptoms reported with carcinoid tumors, a particular type of neuroendocrine tumor or NET, that usually grows in the gastrointestinal tract. These tumors can secrete many different hormone-like substances, such as serotonin, which may affect the thermoregulatory center of the brain and histamine, which can dilate blood vessels located under the skin (ref 7).
Warnings and Precautions
Hot flashes can be due to a variety of causes. Several other conditions can mimic the symptoms of early or premature menopause. Seek prompt medical advice if your hot flashes and night sweats are accompanied by a rapid heart rate, dizziness, tremors, weight loss, diarrhea, or fever or any other unusual symptoms.