Red or skin-colored bumps or welts
When you have an allergic reaction to something, it may trigger welts to appear on your skin. These welts or bumps may appear red or have the same color as the rest of the surrounding skin. Sometimes they resemble bug bites. The patches of raised skin can appear anywhere on the body and often spread rapidly. Sometimes they disappear for a few hours and return with more intensity. The location and shape of the welts often change when they reappear but they may remain close to where they first showed up. The welts usually disappear completely within 24 hours [3], except another reaction starts. According to some dermatologists [4], if the welts last longer than 24 hours in the same location, it may be a sign of something other than hives. Welts that also seem to be filled with fluid are also likely not hives.