Brother has been complaining about being itchy and has red spots/bumps all over. he was told it was allergies. now a month later im starting to get it?

Not all hives..: .. are allergies. A common cause of acute hives is a subclinical (otherwise asymptomatic) viral infection. Another possible explanation for sudden hive onset in 2 individuals is irritant exposure (eg new laundry detergent). A third is an insect exposure such as fleas or bed bugs. Hives for over a month should be discussed with an Allergist to help identify triggers and an effective treatment