Suggest Treatment For Recurrent Diarrhea And Fever In A Child

Hi, My daughter is 4yrs4mnths old. She had laryngotracheal bronchitis til 3yrs for which treatment was done and was resolved. We had shifted from india to saudi arabia 4months ago n after a month of arrival she has got dust allergy which also runs in her maternal side. Recently she has been noted having recurrent loose stools, fever, rashes on face and hand.. When repeated twice with d same symptoms i noticed that she gets tis wihin 6hrs after eating prawns and also mushrooms. Have avoided using both of em nw. But can u suggest a permanent solution for my child s problem