Does Outbreak Of Hives After Taking Medicine Indicate Low Immune System?

My 5 and half yr old daughter always develops hives after taking crocin and now i gave her roxikind and she started complaining of headache and stomach pain. Mostly she gets hives after medication But the same medicines were given to her many times when she was small & there were no allergic reactions when she took crocin or any other mdicine I m really worried Dr. is her immune system weak What s the problem with her system pls help me her weight is 24 kg