Generally, people who are prone to allergic reactions and allergic diseases but cannot find the cause are called “allergic”. People with “allergies” can have various allergic reactions and allergic diseases, such as eczema, urticaria, allergic rhinitis, allergic asthma, etc. Some people are particularly sensitive to certain drugs and can develop drug dermatitis or even exfoliative dermatitis. However, occasional hyperreactivity to a known factor cannot be called “allergy”.