Red itchy bumps

I have been plagued with what I thought were insect bites since Nov 2009. I have been to four different doctors, tried many different topical and oral meds to no avail. The docters tested my blood and stool for any parasites and none were found. I have cats and had them treated for mites, fleas, or anything else they could possibly have, even though they are indoor pets and never go outside. I had my carpets cleaned, my home sprayed for insects, steam cleaned all of our mattresses, and now, I am at a total loss.  These bumps appear at anytime and look like mosquito bites and itch terribly. They started on my stomach, then moved to my shoulders and back. The bumps then appeared on my arms and now on my legs and back to my stomach. Very weird to say the least. I have been using white vinegar to ease the itch which seems to work temporarily. I am also taking Benadryl. After a week or so, the bumps form a scab and that scab lasts for months! After the scab is no longer there, what remains is a permanent scar!
My husband has not been affected, while my granddaughter who lives with us, now has them. My grown daughter, who does NOT live with us, has them and she has been through the same thing! She's gone through every treatment that I have. I believe they came from her husband, who is a meat cutter and also has them. Someone he works with has the same thing and she told him not to worry, they were just dust mites! ( Her husband is from Africa) I don't think so. Whatever this is, it IS contagious! And we can't find the culprit nor the cure. Please help!

[ChitChatNine]

HI and welcome .. geez, I am stumped ... keep trying to find a specialist who can get to the root of this problem .  it looks painful

C~