Coughing, difficulties or irregular breathing, wheezing, itchy throat or mouth, and trouble swallowing are the most typical signs and symptoms of an allergic response. Nausea, vomiting, stomach discomfort, and diarrhea are all symptoms. Itchy skin, red lumps or welts on the skin (hives), and skin redness are all symptoms of hives. A person with these symptoms should be informed that he or she is experiencing an allergic reaction. Allergic reactions are caused by your body's immune system responding to something in your environment that is called an allergen. The two main types of allergies are respiratory allergies and contact dermatitis. Respiratory allergies affect the nose, lungs, and airways. These include asthma, bronchitis, and emphysema. Contact dermatitis is an inflammation of the skin that occurs when skin cells are damaged by something they come into contact with, such as chemicals or pollen. This type of allergy can cause rashes, hives, and other skin problems. The three main types of allergic reactions are acute, chronic, and delayed. Acute reactions occur immediately after being exposed to the allergen. Symptoms include dizziness, fainting, headache, itching, rash, shortness of breath, sneezing, stridor (hoarseness), and tongue swelling. Anaphylaxis is a severe allergic reaction that can lead to death unless treated promptly with medications such as epinephrine.