Allergies pertain to many conditions due to the immune system’s hypersensitive response to normally harmless stimuli. For people with allergies, their body’s immune system perceives an ordinary substance as an outside invader and attacks it. The common allergic responses include swelling, itchy rash, red eyes, bloating, diarrhea, vomiting, sneezing, runny nose, and shortness of breath.
Examples of common allergies include food allergies, hay fever or allergic rhinitis, atopic dermatitis, allergic asthma, and anaphylaxis. The most usual allergens (substances which trigger allergic reactions) include pollen, dust mites, animal dander, insect stings, molds, latex, medications, and certain food like cow’s milk, eggs, nuts, and shrimp. Risk factors include heredity, age, exposure to substances in childhood, pollution, allergen levels, and change in diet.