Regularly using a quality moisturizer is a great defense against dry skin.

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Dry skin is a condition that plagues everyone at some point in his or her lives, especially during cold winter months. While it's not usually a serious health issue, it can be a serious inconvenience involving flaking, itching, irritation and embarrassment. To understand the best way to treat dry skin, it's important to first understand why it occurs -- and to learn the best products and techniques to restore your skin's natural moisture and healthy glow.

Unless there's an underlying, chronic condition at play, dry skin is usually caused by factors in the surrounding environment that strip the skin of its moisture. This could be dry air, such as the pressurized air on an airplane or heated indoor air from a furnace; if this is the case, running a humidifier in your home or office can help keep air, and your skin, from drying out. Cold, dry air outdoors in the wintertime can contribute, as well, especially if it's windy.

Another factor that may cause your face to be flaky is improper skin-care. "Most people with really dry skin are probably using soap that is too strong, or they're taking long hot shower or baths," says Cheryl Karcher, MD, a dermatologist in New York City. Hot water, she explains, actually damages the top layer of skin and leaves it vulnerable to moisture loss. Instead use a gentle, non-foaming facial cleanser, take short, luke-warm showers, and apply moisturizer immediately after washing your face or getting out of the bath.

Karcher recommends a moisturizer with lactic acid, which can help strip away top layers of flaky skin and penetrate healthier layers underneath. If your skin stays dry all day long, you may need to reapply moisturizer two or three times throughout the day. Avoid using alcohol-based toners or astringent, harsh peels and clay-based masks, which draw moisture out of the skin.

In addition to moisturizer, you may want to apply a product containing glycerin or petroleum jelly to particularly dry spots, recommends David McDaniel, MD, assistant professor of clinical dermatology at Eastern Virginia Medical School in Virginia Beach. Glycerin acts as a humectant, attracting and sealing moisture into the skin. While it may seem like something so thick and goopy would clog pores, its molecules are actually too big to penetrate into the skin, he explains.

To tackle your dry skin in a more holistic way, it's important to remember to stay hydrated. It might not seem like the water you drink and the moisture in your skin are directly related, but being dehydrated can keep your tissues and organs from getting the nutrients they need, leaving your skin parched. Watery fruits and veggies can also add to your hydration levels.

Why you may need to see a doctor

If the previous methods don't seem to help your dry flaky skin, pay your dermatologist a visit. You could have a condition such as eczema or psoriasis that requires an individualized treatment plan and, possibly, prescription medication.

Eczema, an autoimmune condition that some researchers believe is related to hay fever and asthma, often appears as dry, flaky patches around the elbows, knees, ankles and wrists -- but it can also appear on the face, especially around the eyes and on the eyelids. Regular moisturizer is unlikely to help eczema, and so your doctor may prescribe (or suggest an over-the-counter version of) a corticosteroid cream or ointment. Harder-to-treat cases of eczema may also require antibiotics, oral or injected steroids, and/or antihistamines to relieve itching.

Psoriasis is another chronic condition characterized by red, irritated skin covered with silvery, flaky scales. Ointments and creams containing corticosteroids, salicylic acid, or retinoids have all been shown to provide relief for the symptoms of psoriasis, although the underlying condition is usually permanent. Daily exposure to sunlight or other sources of ultraviolet rays have also been shown to help reduce the appearance of psoriasis lesions, as have some oral and injectable medications.