Dry, itchy skin is a common winter companion when the humidity drops, especially as we get older.

“The oil-producing glands that lubricate skin shrink and don’t work as efficiently,” says Amy Kassouf, M.D., a dermatologist at the Cleveland Clinic. And that dry winter skin can certainly be uncomfortable.

Some people with find relief with self-help measures, over-the-counter products, or medication. Here are some strategies for three common dry-skin conditions: eczema, psoriasis, and rosacea.

Soothing the Itch of Eczema

More than 30 million Americans have eczema, or patches of red, thick, scaly, itchy skin.

Older adults are at higher risk for asteatotic eczema, which often causes intense dryness and itchiness on the lower legs.

Eczema crops up often in people with asthma or hay fever, but stress, dry heat, allergens, and fragrances and dyes in household products can set it off, too, says Jonathan Silverberg, M.D., director of the Northwestern Medicine Multidisciplinary Center for Eczema at Northwestern University in Chicago.

DIY care: Moisturize several times per day, and run a humidifier when the heat is on at home. Use detergents and soaps that are free of scents and dyes, and wash new clothes and bedding before use.

Occasional use of over-the-counter hydrocortisone cream can also help calm the itch.

See a doctor if you see little change after several weeks of self-care or you have severe itching or patches that blister or ooze.

He or she might prescribe a steroid cream or, in severe cases, an oral immunosuppressant for the itch.

Photo­therapy, which uses ultraviolet light to tame ­inflammation, is an option, too.

Easing the Discomfort of Psoriasis

An estimated 6.7 million Americans have this chronic condition, marked by flaky, itchy, slightly ele­vated patches covered with silvery skin cells.

These “plaques” develop when skin cells grow too rapidly, flaring up when “something triggers the immune system to become overactive,” says Ronald Prussick, M.D., of the National Psoriasis Foundation.

Triggers can include stress, skin injury or infection, allergies, and certain medications.

And “scratching an itchy spot can create new psoriasis in that area,” says Jessica Krant, M.D., a dermatologist on Consumer Reports' medical advisory board.

DIY care: To ease itching and loosen dead skin, soak for 15 minutes in a lukewarm bath to which you’ve added baby oil, oilated oatmeal, or Epsom salt.

A shampoo or an OTC cream that contains salicylic acid can soften plaques; one with coal tar can ­reduce discomfort.

You can also subdue itching with OTC hydrocortisone cream.

See a doctor if self-care doesn’t help. Your doctor might prescribe a biologic drug for inflammation, methotrexate to slow skin-cell growth, or phototherapy.

Coping With Rosacea

A chronic condition that’s more common after age 30, rosacea can lead to redness, bumps, and pustules, usually on the face.

Some people with the condition may also experience dryness, stinging, itching, and burning.

“The skin of rosacea patients is very sensitive,” says John Wolf, M.D., chairman of dermatology at the Baylor College of Medicine in Houston.

Triggers include cold or hot weather, ­indoor heat, stress, sun, wind, alcohol, hot baths, vigorous exercise, and spicy food.

DIY care: Use a gentle facial cleanser and moisturizer before bed, and wear broad-spectrum sunscreen for sensitive skin with an SPF of at least 30.

See a doctor if your symptoms don’t resolve with DIY care or if rosacea causes physical discomfort or distresses you.

Prescription treatments might include a topical anti-­inflammatory cream or an oral antibiotic for more severe inflammation and redness. Laser or light therapy can also be used to reduce redness.

Keeping Dry Winter Skin Healthy

Whether you have eczema, psoriasis, or rosacea, these strategies for dry winter skin can also help.

Turn down the thermostat a few degrees. “It may keep the air from drying out as much, and cooler air is less likely to aggravate your itch,” Silverberg says.

Bathe briefly, and only in tepid water. The hotter the water, the more skin oils are stripped away.

Moisturize after bathing while you’re still slightly damp. Use a product that’s fragrance-free, hypo­allergenic, or made for sensitive skin.

Run a cool-mist humidifier. Or place pans of water near heating vents to moisten indoor air. Humidity should be 30 to 60 percent (40 to 50 percent if you have ­allergies or asthma).

Stick to fragrance-free soaps. Also use detergents made for sensitive skin.