Hypersensitivity

reactions Hypersensitivity reactions occur when the immune system reacts abnormally to a normally harmless substance. They can range from mild to severe in nature, and may include symptoms such as itching, swelling, hives, difficulty breathing, or anaphylaxis. Most hypersensitivity reactions can be controlled and prevented through avoidance of the allergen, early recognition and treatment, and potentially through desensitization and immunotherapy. Hypersensitivity reactions are of importance for public health, as they can cause significant morbidity and even mortality.