I have had a rash, kind of like little blisters/bumps, on my arm for a while. I never thought anything of it as my skin is quite sensitive. For over a week now my head has been burning and itchy so i got my mum to check for head lice (joys of working with children). She said my head is covered in little blisters just like my arm but worse. I havent changed shampoo or anything so i have no explanation. Can this be a side affect to pentasa?