What skin condition is this?

For several months now I have been suffering from constant itching in specific parts of my body. They are mosquito-bite-like welts that are found only on my scalp, buttocks, hips, inner thighs and knees. I scratch them until they bleed, but they never go away. We wash our bedsheets every week, so if it's a parasite, I'm not sure where it's coming from.My husband is not suffering this at all. Does this sound familiar to anyone? I tried looking up the symptoms on WebMD, but the closest one it sounds like is Scabies, and I'm not even sure about that.