Final answer:
A client becoming short of breath and developing hives after eating shrimp for lunch would be considered a food allergy, as the symptoms involve classic allergic reactions like respiratory and skin issues.
Step-by-step explanation:
Food allergies can indeed be life-threatening and are caused by an immune system reaction to harmless substances in certain foods. They are different from food intolerances, which involve the digestive system. The symptoms of food allergies can vary from mild to severe and may include hives, swelling, itching, or gastrointestinal problems like vomiting and diarrhea. In the most severe cases, a food allergy can trigger a potentially fatal reaction known as anaphylaxis, which necessitates emergency treatment. The option that would be considered a food allergy is when a client becomes short of breath and develops hives after eating shrimp for lunch. This reaction involves the respiratory system and the skin, which are classic signs of an allergic response.