We had an infestation, and my poor son experienced constant, horrible eczema flare-ups. He also starting having severe asthma episodes. We battled these tenacious insects diligently for a year, using every tactic possible (exterminators, bombs, sprays, traps, powders, vacuuming, elimination of infected items, etc.), but they kept coming back.
They are extremely tough to get rid of, and as a PP has mentioned above, it is like a horror movie with the larvae, crawling bugs and shedded skin everywhere -- in books, in Lego crannies, in electronics, in drawer corners, in every wool garment that we owned, in my daughter's bed between the mattress and box spring, in storage boxes, in shoes, in pen caps, and crayon boxes. Even after cleaning, spraying and vacuuming diligently for weeks, we still continued to find them in clothes drawers, on books, on socks, on clothes hanging in closets, and on shelves. They were all over my daughter's stuffed animals and in all rooms of the house, crawling on wooden toys, in the closets, upstairs on towels in the linen closet, on beds, under all of the couches as well as between cushions upstairs and downstairs….everywhere. Ugh! It was so disgusting, and I am traumatized by the experience today, some 6 years out. We don't even know where they came from, as we had very few throw rugs and no carpeting in the house -- only hardwood floors! What a nightmare!
We ended up moving to a new house for my family's and my sanity's sake. We threw just about everything out. Any items that we kept sat in bins for a year in an unheated garage. Apparently, subjecting the bugs to below freezing temperatures kills them. We also treated the articles we saved with an insect growth regulator and permethrin.
I have found one dead beetle in the 6 years since we moved, and I immediately kicked into serious biological warfare mode. I never want to go through that horrible experience again!
BTW, if you have pets, they love to feast on pet dander.