The type and severity of allergy symptoms vary from allergy to allergy and person to person. Allergies may show up as itchy eyes, sneezing, a stuffy nose, throat tightness, trouble breathing, vomiting, and even fainting or passing out.
Kids with severe allergies (such as those to food, medicine, or insect venom) can be at risk for a sudden, potentially life-threatening allergic reaction called anaphylaxis or anaphylactic shock. Anaphylaxis can happen just seconds after being exposed to an allergen or not until a few hours later (if the reaction is from a food).
So doctors will want anyone diagnosed with a life-threatening allergy to carry an epinephrine auto-injector in case of an emergency. Epinephrine works quickly against serious allergy symptoms; for example, it reduces swelling and raises low blood pressure.
Airborne allergens can cause something known as allergic rhinitis, which usually develops by 10 years of age, reaches its peak in the teens or early twenties, and often disappears between the ages of 40 and 60.
Symptoms can include:
When symptoms also include itchy, watery, and/or red eyes, this is called allergic conjunctivitis.
Allergic reactions can vary. Sometimes, a person can have a mild reaction that affects only one body system, like hives on the skin. Other times, the reaction can be more serious and involve more than one part of the body. A mild reaction in the past does not mean that future reactions will be mild.