The exact cause of the hot flashes is not fully understood, but the declining estrogen levels that occur as a woman approaches menopause are thought to play a role. A disorder in thermoregulation (methods the body uses to control and regulate body temperature) is responsible for the sensation of heat, but the exact way in which hormone levels affect heat regulation is not well understood.
While hot flashes are typically associated with the menopause in women, certain uncommon medical conditions can also lead to hot flashes and disorders of the body's ability to regulate temperature. One example is the carcinoid syndrome, which occurs due to a type of endocrine tumor that secretes large amounts of the hormone serotonin. Hot flashes can also develop as a side effect of some medications and can sometimes occur in association with severe infections or cancers.
Hot flashes often begin before any menstrual changes suggestive of menopause develop, so hot flashes may appear even years prior to the actual menopause. Hot flashes always involve the sensation of heat, but other symptoms may also be associated as follows:
The symptoms of a hot flash typically develop suddenly, without warning, and last from less than one minute to several minutes.
It is appropriate to contact a health-care professional if a woman is experiencing disturbing or uncomfortable hot flashes.
As with any medical condition or complaint, a health-care professional will begin by taking a complete medical history. He or she will ask the woman to describe the hot flashes, including how often and when they occur, and if there are other associated symptoms. A physical examination will be used to help direct further testing if necessary.
Blood tests may be performed if the diagnosis is unclear, either to measure hormone levels or to look for signs of other conditions (such as infection) that could be responsible for the hot flashes.
There are a variety of treatments for hot flashes.
Some of these have not been tested by clinical studies, nor are they approved by the US Food and Drug Administration (FDA).
Estrogens or a combination of estrogens and progesterone (progestin) have been shown to significantly decrease the frequency and intensity of hot flashes.
However, long-term studies (the NIH-sponsored Women's Health Initiative, or WHI) of women receiving combined hormone therapy with estrogen and progesterone showed an increased risk for heart attack, stroke, and breast cancer when compared with women who did not receive HT. Studies with estrogen therapy alone showed that estrogen was associated with an increased risk for stroke, but not for heart attack or breast cancer. Estrogen therapy alone, however, is associated with an increased risk of developing endometrial cancer (cancer of the lining of the uterus).
More recent medical research has suggested that in younger postmenopausal women, hormone therapy may not have these same risks as in the older postmenopausal women who participated in the WHI studies, and research is ongoing to determine the risks and benefits of hormone therapy in younger postmenopausal women and women around the age of menopause.
The decision regarding hormone therapy, therefore, should be individualized for each woman, recognizing her medical history, the severity of the symptoms, and the potential risks and benefits of hormone administration.
A number of non-hormonal prescription medications and alternative treatments have also been used for the treatment of hot flashes (See next section).
Both oral and transdermal (applied via a cream or patch to the skin) estrogen are available either as estrogen alone or estrogen combined with progesterone. All available prescription estrogen replacement medications, whether oral or transdermal, are effective in reducing the frequency of hot flashes and typically reduce the frequency of hot flashes by about 80% to 90%. However, as described above, hormone therapy may carry some health risks.
Many women turn to alternative therapies for the treatment of hot flashes. These have included herbal products, vitamins, and plant estrogens as well as other substances. Doctors can be reluctant to recommend alternative treatments because these nonprescription products are not controlled by the U.S. Food and Drug Administration (FDA). Because they are not regulated like prescription medications, their ingredients and strength can vary from manufacturer to manufacturer and testing and proof of safety is not required for marketing of these products as it is with prescription medications. Long-term, scientifically controlled studies for these products are either lacking or have not proved the safety and effectiveness of the product.
Some popular alternative treatments for menopausal hot flashes include:
Scientific studies to prove the safety and effectiveness of these products have not been performed.
There has been increasing interest in recent years in the use of so-called "bioidentical" hormone therapy for perimenpausal women. Bioidentical hormone preparations are medications that contain hormones that have the same chemical formula as those made naturally in the body. The hormones are created in a laboratory by altering compounds derived from naturally-occurring plant products. Some bioidentical hormone preparations are U.S. FDA-approved and manufactured by drug companies, while others are made at special pharmacies called compounding pharmacies, which make the preparations on a case-by-case basis for each patient. These individual preparations are not regulated by the FDA, because compounded products are not standardized.
Advocates of bioidentical hormone therapy argue that the products, applied as creams or gels, are absorbed into the body in their active form without the need for "first pass" metabolism in the liver and that their use may avoid potentially dangerous side effects of synthetic hormones used in conventional hormone therapy. However, studies to establish the long-term safety and effectiveness of these products have not been carried out.
Some women report that exercise programs or relaxation methods have helped to control hot flashes, but controlled studies have failed to show a benefit of these practices in relieving the symptoms of hot flashes. Maintaining a cool sleep environment and the use of cotton bedclothes can help ease some of the discomfort associated with hot flashes and associated night sweats.
Hot flashes associated with the menopausal transition are not a life-long problem and can be effectively treated in most women if necessary. About 80% of women will stop having hot flashes five years after the onset of hot flashes. Less commonly, in about 10% of women, hot flashes can persist for up to a decade.
It is impossible to predict which women will experience hot flashes in association with the perimenopause or the degree of severity of the hot flashes. Perimenopausal hot flashes may be controlled by some of the treatment measures described above, but are not preventable.
