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. But 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 when taking certain medications or consuming alcohol, as well as with certain medical conditions, such as endocrine disorders, cancer and its treatments and rare tumors.
Hot Flashes Explained
The biological 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 that occurs in association with the menopausal transition 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 -- the absence of menstruation for 12 consecutive months -- between age 45 and 55. It occurs because the number of immature eggs in the 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 the hot flashes during these times. A history of early menopause in your family increases your risk for this condition. Cigarette smoking has also been shown to increase your risk for early menopause.
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 after they stop having periods -- sometimes as early as their late teens or early 20s. Usually POI occurs 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 lose ovarian function after a simple hysterectomy -- removal of the uterus but not the ovaries. Tumors or conditions affecting the hypothalamus or pituitary gland of the brain can also cause premature menopause due to impaired secretion of hormones that 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 differ in that they are unrelated to declining ovarian function. Alcohol -- particularly beer, sherry and some red and dessert wines -- might cause flushing due to their high concentration of histamine, a substance that dilates blood vessels. An inherited enzyme deficiency, common among people of Asian heritage, is another frequent cause of alcohol-induced flushing reactions due to impaired alcohol metabolism.
The supplement niacin can trigger flushing, especially when taken in high doses. Niacin 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)
-- certain antidepressants, such as fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil) and desvenlafaxine (Pristiq)
Non-Reproductive Hormonal Disorders
Several non-reproductive hormonal disorders can cause flushing, with or without associated sweating. Hyperthyroidism and pheochromocytoma are examples of such conditions. With hyperthyroidism, excess thyroid hormone increases the body's metabolic rate, causing overheating and increased sweating. Pheochromocytoma is a rare tumor -- usually noncancerous -- that most frequently arises in the adrenal gland, located on top of the kidney. This tumor secretes epinephrine, norepinephrine and dopamine, neuroendocrine substances that act as both hormones and brain signaling chemicals. They can provoke dilation of blood vessels, particularly in the face, which might trigger episodic flushing attacks. Other common signs and symptoms associated with both hyperthyroidism and pheochromocytoma include a rapid heart rate, anxiety, tremors and high blood pressure.
Cancer and Its Treatment
Hot flashes can occur with certain types of cancer and cancer treatment. Carcinoid tumors are a type of slow-growing neuroendocrine tumor (NET) that usually grows in the gastrointestinal tract. Some carcinoid tumors secrete various hormone-like substances such as serotonin, which may affect the thermoregulatory center of the brain, and histamine, which can dilate blood vessels near the skin surface. Another type of NET called a VIPoma, which occurs in the pancreas, can also cause flushing similar to a carcinoid tumor.
Hormonal therapy, such as tamoxifen (Soltamox), used to treat breast cancer often leads to hot flashes. This is due to the estrogen-blocking effects of the medication, which can affect the thermoregulatory center in the brain. Certain chemotherapy drugs used to treat various types of cancer in young girls and women can trigger early menopause, leading to hot flashes. Examples include carboplatin, chlorambucil (Leukeran), cisplatin, cyclophosphamide and lomustine (Gleostine).
Warnings and Precautions
Hot flashes in young women can occur with a variety of conditions, in addition to those previously discussed. While early or premature menopause is often the leading concern for many women and their healthcare providers, several other ailments can mimic the symptoms of these conditions -- some more serious than others. Therefore, it's important to see your doctor as soon as possible if you experience symptoms that seem to be hot flashes. Seek prompt medical care if your hot flashes are accompanied by a rapid heart rate, dizziness, tremors, weight loss, diarrhea, fever or any other unusual symptoms.
Reviewed by: Tina M. St. John, M.D.