Do bed bugs transmit any diseases?

NO. They are known carriers of many diseases, but they have not been shown to be transmitters of these diseases. The reaction to bites is highly variable depending on individual sensitivity. A bite can look like a tiny pin prick or a big, ugly welt. Even a dermatologist may not know what type of insect bit you. The welts and classic triangle pattern seem more common, but they can look similar to mosquito bites, hives, allergies and bee stings.