Learn more about allergies, your immune system’s overreaction to something that’s not harmful — like pollen, pet dander and certain foods. Allergic reactions are symptoms that happen after you touch, inhale or eat something you’re allergic to. Common causes include foods, plants, medications and pets. Substances that come into contact with the skin, such as latex, are also common causes of allergic reactions, known as contact dermatitis or eczema. [35] Skin allergies frequently cause rashes, or swelling and inflammation within the skin, in what is known as a wheal and flare reaction characteristic of hives and angioedema. [36] A 21-year-old male arms during an allergy skin test. A. Symptoms of Allergic Reactions Most allergic reactions are mild, consisting of watery and itchy eyes, a runny nose, itchy skin, and some sneezing. Rashes (including hives) are common and often itch. Hives, also called urticaria, are small, red, slightly elevated areas of swelling (wheals) that often have a pale center. Find out about allergies, including typical symptoms, common allergies, when to get emergency medical help and allergy testing and treatments. Allergic Reaction Allergic reactions happen when you come into contact with an allergen. Your immune system reacts by releasing histamines and other chemicals into your blood, causing symptoms. An allergic reaction occurs when your body attacks a foreign, and typically harmless, substance. Learn about symptoms, prevention, and more. Symptoms Allergy symptoms depend on what allergen is involved. The symptoms can affect the airways, sinuses and nasal passages, skin, and digestive system. Allergic reactions can range from mild to severe. Sometimes, allergies can trigger a life-threatening reaction known as anaphylaxis. Hay fever, also called allergic rhinitis, can cause: Sneezing. Itching of the skin, nose, eyes or roof of. Allergic response Dermatographic urticaria. An allergic response is a hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in everyone. An allergic response may cause harmful symptoms such as itching or inflammation or tissue injury. The meaning of ALLERGIC is of, relating to, affected with, or caused by allergy. How to use allergic in a sentence.