Q:  I was embarrassed when a friend stayed at my house recently, and maybe you will find my story worth sharing. My entire family has a lot of allergies, so we have no pets and use area rugs over our wood floors. My friend has worse allergies than we do, and her skin started itching and her asthma got worse.

I was pretty sure it wasn't dust mites, because I buy new pillows every two or three years, keep them (and our mattresses) in moisture-proof covers, and wash all the bedding, including comforters and mattress covers, regularly. My vacuum has a great HEPA air purifier, and I vacuum often. My friend had dropped an earring in her room, and we both were looking for it. She moved a corner of the rug back and we found tons of dust in and around the rug pad.

I moved the rug out into the garage so I could get it (and all the other rugs I own) cleaned. It hadn't occurred to me to vacuum the underside of the area rugs. What can I do to keep this from happening again?

A: What a horrible feeling, to think you're doing so many things right, which you are, and then discover something you missed. And then to have a friend find it for you. I'd be embarrassed, too.

You hit the nail on the head by using a vacuum with a HEPA air filter, replacing your pillows every two or three years, max, and using pillow and mattress protectors. Those really do help reduce allergens. But especially in bedrooms, or any room you spend a lot of time in, dust and dander filters through carpeting and area rugs. Like you, a lot of people with allergies go with hardwood or stone floors throughout the house, and some don't use area rugs at all. I love area rugs because they add so much to any room, but if my allergies were that bad, I would reconsider.

Sometimes, though, the area rug backing, or even the rug pad or its backing, dries out and turns into dust. That might be part of what you saw under your rug. Also, some rug pads are porous and can trap dust, mold, mildew, and allergens, and typically don't get vacuumed or cleaned often, if at all. Other rug pads, such as the inexpensive mesh type, even smell bad as they get old. That, plus the extra dust and dirt, could cause reactions for some people.

It's a good idea to replace rug pads every four or five years. Some types may last longer but not much more than 10 years. For the best selection of non-slip rug pads that will suit your needs, and to help keep your home cleaner, visit a business that specializes in cleaning area rugs, or a rug retailer.

Have a design dilemma? Jennifer Adams is an award-winning designer, writer and TV personality. Send your questions to AskJennifer@JenniferAdams.com or on Twitter: @JenniferAdams. For more design ideas, visit Jennifer's blog on her website at www.jenniferadams.com.