When the temperature drops, it's normal for your hands and feet to feel chillier than, say, your legs, arms, or midsection.

That's because your body's natural response to the cold is to narrow the blood vessels in extremities, such as your fingers and toes. That restricts the circulation of warming blood to hands and feet, which conserves your body's heat.

We're more likely to have to deal with cold hands and feet as we get older, as the insulating layer of fat beneath the surface of the skin thins and blood flow to fingers and toes diminishes.

But for some people, the response to temperature change is extreme.

The tiny blood vessels in their fingers and toes almost clamp shut in response to temperature reductions of even a few degrees. Sometimes it occurs as a result of emotional stress.

In those cases, cold hands and feet may be caused by an uncomfortable but usually benign condition known as Raynaud's.

If you have cold hands and feet even when the temperature is moderate—or in stressful situations—here's what you need to know to stay warm.  

Symptoms of Raynaud's

Alternately referred to as Raynaud's disease, phenomenon, or syndrome, about 5 percent of people in the U.S. have this exaggerated reaction to the cold or stress, according to the National Institutes of Health.

A Raynaud’s “attack” may occur if you’re startled, stressed by something like a fast-approaching deadline, or exposed to a sudden drop in air temperature, even one as minor as walking into an air-conditioned room.

It's most likely to cause markedly cold hands and feet, especially fingers. Less often, the ears, nose, and even the knees may be affected. During an episode, your fingers and toes may turn white or purplish-blue.

As you warm up—or relax—blood vessels in your cold hands and feet widen again and blood flow to your extremities begins to normalize. Your skin may then turn pink or red before returning to its usual color. Throughout an episode, you may have numbness or pain in the affected digits.

Doctors aren't sure what triggers the development of primary Raynaud's, the most common form of the condition.

Secondary Raynaud's, which tends to bring more intense attacks, is associated with a number of underlying conditions, including rheumatoid arthritis, lupus, and scleroderma.

General risk factors for Raynaud's, according to the National Heart, Lung, and Blood Institute, include being female, living in a cold area, age (primary Raynaud's usually starts between 15 and 30; secondary, at about 30), a family history of the condition, smoking, and exposure to chemicals such as vinyl chloride, found in a variety of plastic products.

An injury to your feet or your hands, such as a broken wrist, may also increase the likelihood of Raynaud's, as can repetitive stress conditions such as carpal tunnel syndrome, repetitive actions like typing, and frequent use of vibrating tools, such as jackhammers.

In addition, certain medications, such as the chemotherapy drugs cisplatin and bleomycin, and the high blood pressure drugs known as beta-blockers may lead to Raynaud's symptoms.

And an April 2016 review of studies published in the British Journal of Clinical Pharmacology suggests that medication-induced Raynaud's may be underestimated.

The French researchers who conducted the review noted that chemo drugs are most likely to cause problems, followed by beta-blockers. They also found evidence suggesting that cancer treatments such as imatinib (Gleevec), dasatinib (Sprycel), and sorafenib (Nexavar) may be involved as well.

Other classes of medications linked to Raynaud's include migraine drugs such as the triptans and ergotamines, antidepressants such as the selective serotonin-reuptake inhibitors, decongestants, and more.

If You Think You Have Raynaud's

There's currently no cure for Raynaud's, but a number of lifestyle strategies and medical therapies can help curb symptoms.

Avoid the cold when possible—easier said than done, of course—and dress to preserve body heat when it's chilly, with long underwear, gloves, warm socks, and a hat.

If you smoke, work at quitting, and if stress seems to bring on episodes, practice ways to ease tension. A couple of minutes of deep, slow breathing can help.

Avoid medications that may bring on Raynaud's, and if you're unsure whether yours can, ask your doctor or pharmacist.

If you have a history of Raynaud’s and are taking any of the medications that can bring it on, ask your doctor whether you can switch to a different one. 

During an episode, tuck your hands under your armpits, swing them in a windmill pattern, or put your hands or feet in warm water.

If you're experiencing bothersome symptoms that don't ease with lifestyle changes, see your doctor, who may refer you to a rheumatologist.  

In some cases, prescription medications such as calcium channel blockers may be needed to help keep blood vessels from constricting. For secondary Raynaud's, you might need more potent medication such as topical nitroglycerin, hospitalization if an attack doesn't resolve, or even surgery to cut nerves that set off blood vessel constriction, according to UpToDate, an evidence-based physician website.

In all cases, be sure to tell your doctor about all over-the-counter and prescription drugs, dietary supplements, and herbal remedies you take. And see a doctor promptly if you have Raynaud's and develop an open sore on one of the affected digits.