I would suggest a pest control professional. Looks to me like 'brown recluse' spiders have a nest somewhere beneath or in your home. The yellowish purple swelling which would have like a ring around it, like a dark purple or blue ring, if it was on your arm or something. There usually are 2 distinctive holes, like fang marks, in the middle of the swelling. These spiders can be deadly! An infestation like that needs a professional. Yes in this case I would suggest spraying the yard also. These brown recluse and the black widow are the only truly deadly poisonous spiders native to most the U.S.A. Not all people have severe reactions to them, but if you have developed hives, that means a heightened sensitivity to them. If you have Children, i definitely would advise you let a professional take care of this problem. This year I have heard of a lot of brown recluse infestations. These spiders can be deadly, so please get yourself a professional, and soon! They are not very big but here is a picture.
You can use cayenne pepper,put a small amount where you see them congregating even outside as long as it is not on the ground not that it would harm anything but dampness, put it all around your baseboards in your basement even your porch hope this helps.....peace