How to Prevent: To keep skin from flaking, avoid products that contain alcohol, which is drying. Instead, use a gentle cleanser and switch to a richer moisturizer, such as Neutrogena Norwegian Formula Moisturizing Cream ($10.50 at drugstores). “I especially use it after skiing,” Felderman says.

How to Treat: Continue to wash with a mild cleanser, such as Cetaphil Gentle Skin Cleanser ($8 at drugstores). Moisturize several times a day. At night apply a heavy-duty lotion, such as Lac-Hydrin Five Moisturizing Lotion. Then use a hydrating mask weekly. RS pick: Zia Natural Skincare Oat Milk Detoxifying Mask ($23, www.zianatural.com).

When to See a Professional: If skin sheds excessively, a light chemical peel can remove the dead top layer of skin in one office visit. If flaky areas are itchy and irritated, you may have an allergy. A dermatologist can prescribe the appropriate cream.