When i drink whiskey i brake out in hives. why is that? should i be worried?

Allergies: Sounds like you're allergic to whiskey. Stop drinking it.

See an Allergist: An IgE immune response to whiskey would be quite rare, but possible. Rye allergy (reaction would occur with many beers also), or sensitivity to an additive would be expected. Alcohol itself decreases threshold for histamine release, which would explain hives for non-allergic person. Important to determine the cause as treatment strategy (and knowing what else to look out for) varies.