Peanut Allergy: Causes, Symptoms, Treatment and Symptom Relief
A peanut allergy is a common type of food allergy, which occurs when an individual’s immune system overreacts to exposure to peanuts or products that contain peanut proteins. In its most severe form, a peanut allergy can result in death. About 1% of the population are allergic to peanuts whereas half of them suffer from a severe allergy. The only effective treatment for this condition is the complete removal of peanuts and foods with peanut proteins from the diet.
Peanuts are the seeds of a plant called Arachis hypogaea from the legume family (along with beans, lentils, peas and soybeans). About a quarter of the peanut kernel is made up of proteins. Most of these proteins are known to be allergenic. Many people who are allergic to peanuts also have cross-reactivity to other legumes or tree nuts.
An adverse reaction to peanuts usually occurs when an allergic person encounters a peanut protein in food. However, in some very sensitive individuals it can also occur through skin contact, especially when touching the eyes. The immune system perceives the peanut protein to be a dangerous invader and triggers the release of IgE antibodies to combat this threat. In turn, the IgE antibodies activate the release of histamines, which are eventually responsible for most allergy symptoms.
Peanut allergies can be triggered by a much smaller amount of allergenic substance than any other type of food allergy. Kissing or having skin to skin contact with another person who has recently eaten peanuts can be enough to cause an allergic response in some highly sensitive patients. Also, foods that do not contain any peanut ingredients but are packaged in the same facility as peanuts may trigger reactions in highly sensitive people.
Thermal and chemical treatment of peanuts (as in cooking or food processing) does not decrease the strength of their allergens. This makes a peanut allergy different from most other food allergies, in which these processes tend to reduce the allergic response. Roasting can sometimes even increase the strength of peanut allergens.
The prevalence of peanut allergies in children appears to be on the rise. This is because the growing numbers of children are eating peanuts and foods containing peanuts at a very young age. In addition, peanuts are being increasingly used in topical creams, which may also contribute to the rise in allergies. Fortunately, at least 20% of young children eventually outgrow their peanut allergy.
Causes of Peanut Allergies
Peanut allergies are triggered by peanuts and their proteins when they are digested, inhaled or come in contact with the skin of a sensitive person. Allergic people should educate themselves on all forms of peanuts so that they can avoid problematic products. The most common names of foods and ingredients which contain peanut proteins include:
- Arachis oil
- Cold-pressed or expressed peanut oil
- Groundnut oil
- Hydrolyzed plant protein
- Hydrolyzed vegetable protein
- Mixed nuts
- Monkey nuts
- Natural flavoring
- Peanut butter
- Peanut flour
Peanuts are also present as an ingredient in many types of unsuspected foods. Foods and other products that often contain hidden peanut-derived ingredients are:
- Breakfast cereals
- Cereal bars
- Chinese, Thai, Indonesian, Vietnamese, African and Mexican dishes
- Curry or satay sauces
- Ice cream
- Nutrition and energy bars
- Salad dressings
- Topical ointments
- Vegetarian dishes
Patients with peanut allergies also need to avoid foods that list artificial nuts as an ingredient. These are peanuts, such as mandelonas, that have been reflavored to taste like a tree nut (almond).
Extremely sensitive individuals must be careful not to have skin contact with any type of peanut product or another person who has recently consumed peanuts.
Sometimes, food packaging may include a statement (appearing on the food label but not in the ingredient section) that the food was processed on equipment that also processes foods containing peanuts. However, this statement is not mandatory.
Related Allergies and Conditions
A peanut is a member of the legume family and, therefore, peanut-allergic individuals may be also allergic to other legumes. Though cross-reactions are generally uncommon, they can be just as dangerous as a peanut allergy itself. Legumes that may cause a reaction in patients with peanut allergy include:
- Black-eyed peas
- Butter beans
- Green beans
- Kidney beans
- Lima beans
- Soybeans (including unrefined soybean oil)
Patients with peanut allergies should use caution when consuming tree nuts because nearly half of peanut-allergic adults are also allergic to a certain type of tree nut (see also an article on tree nut allergies). Furthermore, individuals allergic to peanuts may also be allergic to seeds (e.g., lupin beans or sesame seeds).
Some people allergic to peanuts may also have oral allergy syndrome. It is characterized by an itching, burning or swelling in the lips, throat, palate or tongue after eating certain foods at a certain time of the year. A cross-sensitivity between the similar proteins present in the food and pollen is usually to blame.
Symptoms of Peanut Allergies
Sensitive individuals who have been exposed to a peanut protein will usually begin to experience symptoms in a few minutes, although some reactions may occur up to several hours later. The most common symptoms include itchiness, swelling, hives, sneezing and coughing, nausea and stomach pain. Severe reactions can result in potentially life-threatening anaphylactic shock, characterized by difficulty breathing and a drop in blood pressure. Mild to moderate symptoms of an allergic reaction to peanuts may include:
- Skin problems including redness, itchiness, swelling and hives
- Throat and breathing problems including difficulty swallowing, hoarseness, wheezing, repetitive coughing and shortness of breath
- Gastrointestinal problems including nausea, vomiting, stomach pain and diarrhea
- Circulatory problems including dizziness, paleness, low blood pressure and loss of pulse
More severe symptoms that may appear with or without mild to moderate symptoms include:
- Tightening in the throat or chest
- Severe shortness of breath
- Loss of consciousness
Diagnosing Peanut Allergies
The techniques for diagnosing peanut allergies are similar to those used in other food allergies. To determine what type of food causes the allergy, the doctor may ask the patient to keep a diary of foods and symptoms. Other commonly used methods of diagnosing a food allergy have been described in this article.
Treatment and Prevention for Peanut Allergies
Strict avoidance of peanuts and all foods with peanut proteins is the only method of successfully treating peanut allergies. Patients must always check the labels of the foods and other products (e.g., cosmetics) they purchase and inquire about ingredients and food preparation when they are eating away from home. Allergic individuals need to educate themselves on foods that contain peanut proteins, diverse names of peanut ingredients as well as alternative names of the peanuts themselves. If not sure, sensitive individuals should better avoid products with unfamiliar ingredients because just a trace amount of peanut protein can trigger an allergic reaction that can be potentially fatal.
Parents of children with peanut allergies should inform their schools, daycare facilities, babysitters, clubs, and friends and relatives they frequently visit of the child’s condition and emergency treatment procedures.
Allergic individuals are often given an allergy kit that includes an injection of epinephrine reserved for the most severe cases of allergic reactions that involve anaphylactic shock. Epinephrine is a powerful bronchodilator and a blood pressure booster. People susceptible to severe peanut reactions should carry an allergy kit containing epinephrine with them at all times.
An ancient remedy – an activated charcoal – is effective at reducing the severity and progression of a food allergy reaction. It is a powerful adsorber (not absorber) binding to the allergens in the peanut and blocking them from interacting with the immune system. However, this therapy should not be tried without a doctor’s approval and should only be used after another type of treatment, such as an epinephrine shot, has been administered.
Relief for Peanut Allergy Symptoms
Certain medications can be used to help reduce the severity of symptoms once an allergic reaction to peanuts has occurred. However, these drugs should not be viewed as a treatment for peanut allergies. Medications for the relief of symptoms associated with food allergies have been described in this post.
Where to Find Related Information: Managing Peanut Allergies