5y/o Male, Came In From Playing Had Rosey Red Check

5y/o male, came in from playing had rosey red check with perfect red circles on cheecks, with in an hour entire body was covered with bumps and whelps raised, itching at tha time, treated with benadryl seemed ok, Today same routine as above except about an hour ago woke crying in pain with and itching, could this be a "sun related allergy"