There are various synonyms available for "type I allergic reaction." It is commonly known as an immediate hypersensitivity reaction. This reaction occurs within seconds or minutes of exposure to allergens. Another term used is anaphylactic reaction which is a severe form of type I allergy. It results in symptoms such as swelling, hives, breathing difficulties, and low blood pressure. It can also result in life-threatening conditions such as anaphylactic shock. Some other synonyms for type I allergic reaction include immediate hypersensitivity, IgE-mediated reaction, and atopic reaction. These terms describe the same phenomenon, and understanding the multiple ways to describe allergic reactions can help improve communication between healthcare providers and patients.