Sneezing, itchy eyes and a runny nose are common signs of allergies, but experts say allergic reactions can range from mild seasonal symptoms to life-threatening emergencies.

On The Spark, Dr. Timothy Craig, an allergy and immunology specialist at Penn State Health and professor of medicine and pediatrics, discussed what allergies are, how they develop and why recognizing symptoms early is important.

An allergy occurs when the immune system overreacts to a substance that is typically harmless. Common triggers include pollen, dust mites, pet dander, mold, insect stings, certain foods and some medications. While many people experience seasonal allergies, Dr. Craig explained that allergies can develop at any stage of life.

He also highlighted the difference between food allergies and food intolerances. A food allergy involves the immune system and can lead to severe reactions, while a food intolerance primarily affects the digestive system.

For people experiencing symptoms, diagnosis may include a review of medical history, skin-prick testing, blood tests or elimination diets. Dr. Craig said managing allergies begins with identifying and avoiding triggers, taking prescribed medications when needed and recognizing the warning signs of anaphylaxis, a severe allergic reaction that requires immediate medical attention.