Mild allergies, like hay fever, are highly prevalent in the human population and cause symptoms such as allergic conjunctivitis, itchiness, and runny nose. Allergies can play a major role in conditions such as asthma. In some people, severe allergies to environmental or dietary allergens or to medication may result in life-threatening anaphylactic reactions.
A variety of tests now exist to diagnose allergic conditions. Treatments for allergies include allergen avoidance, use of antihistamines, steroids or other oral medications, targeted therapy, and immunotherapy to desensitize the response to allergen.