Red Rashes

My girl will have red rashes around her body everytime she recovers from her sick. Is it because the side effect of taking medicine? Can even Paraceptamol cause allergic? I ain't sure. Luckily the red rashes will not become severe eczema and will subside after few days without any medication. I was panicked the first time i saw those red rashes over her body, but now i am so immune by seeing those red rashes.