A peanut allergy is a potentially deadly allergic reaction to the proteins found in peanuts. When an allergic individual comes into contact with a peanut protein (usually by eating, though much less commonly by touching or inhaling the protein) the immune system triggers an allergic response. The only way to successfully treat a peanut allergy is to completely remove peanuts and products containing peanuts from the diet.

Peanut allergies are one of the most common causes of food-related deaths. Individuals who are sensitive to peanuts can go into anaphylactic shock after ingesting even a trace amount of peanut protein. Roughly 100 people die each year in the United States as a result of food–related anaphylactic shock, according to the American Academy of Allergy, Asthma and Immunology (AAAAI). Patients who are at risk for this potentially deadly allergic reaction are often advised to carry an epinephrine shot (allergy kit) by their physician. Epinephrine helps to reverse the severe breathing problems associated with anaphylactic shock and raises blood pressure.

It is important to note that peanuts are not actually nuts but part of the legume family (along with peas, beans and lentils). Peanuts do not belong to the tree nut family that includes cashews, almonds, pecans, walnuts, beechnuts, Brazil nuts, pistachios and more. Tree nut allergies are less common than peanut allergies.

Approximately 3.3 million people in the United States have an allergy to peanuts and/or tree nuts, and roughly 1.5 million people suffer from a severe allergy to peanuts in the United States, according the AAAAI. Though many types of food allergies are outgrown after childhood, only about one in five people outgrow an allergy to peanuts. A few individuals will find that their allergic response diminishes over time, though the majority of people with peanut allergies will need to carefully avoid peanut and peanut products throughout life. Only a physician is qualified to determine whether a person can reintroduce peanuts to the diet.

Symptoms of a peanut allergy usually include swelling, hives, itchiness, redness, nausea and stomach pain. Treatment of the symptoms associated with peanut allergies usually involves the use of medications, such as antihistamines and bronchodilators.

The development of a peanut allergy is believed to occur for most during infancy. Dietary exposure at a young age may result in allergy development in some individuals. People with a family history of allergies are more likely to develop a peanut allergy.

New developments in peanut allergy treatment are making it possible for some individuals to accidentally consume several peanuts without having a reaction. Though this treatment is not considered a cure, and does not allow a patient to knowingly consume peanuts, it does reduce the threat of accidental consumption under which many people with this allergy are forced to live.