Nut Allergy: Symptoms, Causes, Risks, Complications, Diagnosis and Treatment

a woman who's allergic to nuts


Many would agree that tree nuts and peanuts are one of the most common allergies- causing foods. Nuts and peanuts are different in the sense that nuts grow on trees while peanuts are legumes that grow underground. People who are allergic to peanuts can also be allergic to tree nuts (e.g. almonds, macadamia nuts, walnuts, cashew, and pistachio) since they both contain a similar structure of proteins.

Like the others with known allergies, the body’s immune system exaggeratedly reacts to proteins in peanuts or nuts. Whenever an individual eats or sometimes handles these foods, their body sees these proteins as an enemy or harmful invaders. The body then releases histamine in response to the allergic reaction causing contraction of smooth muscle and dilation of capillaries.


The allergic reactions of individuals to these types of foods (nuts and peanuts) can be different from other individuals. The following signs and symptoms can be experienced by persons who are allergic to nuts and peanuts.

  • Hives
  • Redness
  • Eyes become itchy, watery or swollen
  • Coughing
  • Nasal congestion
  • Wheezing
  • throat tightness
  • difficulty swallowing
  • hoarseness
  • vomiting
  • diarrhea
  • swelling
  • Difficulty of breathing
  • anaphylaxis (severe reaction); this may begin with the less severe reaction which quickly worsens leading the individual to have a difficulty of breathing or can even pass out and if left untreated, it could be fatal.


When the person experiences an allergic reaction to tree nuts or peanuts, the body’s immune system starts fighting these protein substances which are perceived as attackers or invaders of the body and not recognizing them as harmless. The overreaction of the body then releases histamine into the bloodstream and manifests the symptoms of the allergy.

A person can be exposed to nuts or peanuts in several ways:

  • Eating nuts or ingesting peanuts or peanut-containing food (direct contact).
  • Cross-contact or the unintended introduction of nuts/peanuts into a product during handling or processing
  • Though it is a rare case, since the protein has to be ingested, people can get allergy through inhalation or breathe in small particles of nuts or peanuts or aerosols of foods containing nuts or peanuts like peanut cooking oil spray, peanut flour. This usually happens in an enclosed area, like bars or restaurants where there are lots of nuts or peanuts being cracked and that the allergic person might inhale and swallows the protein thus creating the allergic reaction.

4Risk Factors

You are at risk or have a greater chance of developing nut or peanut allergy if:

  • You have family members with allergies too (hereditary).
  • You have other types of allergies or an allergy to one food already.
  • You have been allergic to peanuts in the past.
  • You are a toddler or an infant. These children are prone to allergies especially to food since their digestive systems are not that mature yet. Other people may outgrow certain food allergies over time like eggs, milk, and wheat but for tree nuts and peanuts, it might take a lifetime ordeal for them.


If the symptoms of nut and peanut allergies are not managed immediately, it might lead to anaphylaxis which could be life-threatening.


A precise diagnosis is very vital in this allergic reaction.

Medical History Taking

The doctor asks something about past allergic or hypersensitivity reactions and also some family history about the allergy and current manifestations of the allergy. Describe what happened and tell the doctor what transpired after eating the nuts or peanut-containing food, the duration of the reaction, the type of nuts or peanut eaten and how much of it have you eaten.

Physical Examination and assessment

This usually follows after history taking. The doctor assesses the allergic site for the presence of symptoms.

Food record or food diary

The doctor may ask you to provide a record of eating habits, symptoms, and medications used like food supplements and vitamins. Information taken from these may guide the allergist to determine if the client has a nut or peanut allergy or if the symptoms suggest other causes like food intolerance. 

Blood tests and Skin-prick test

These are used to determine if there is the allergen-specific immunoglobulin E that combines with the allergens and cause the secretion of chemicals (histamine) that cause the symptoms. Skin-prick tests are done by placing a glycerinated allergen extract drop on the client’s skin, which is then pricked with a needle. This process is repeated with two controls, a histamine drop, used to get an allergic reaction and a saline drop designed to produce a negative or no reaction. A raised bump is observed when the client is positively allergic to that particular substance.

Food challenge

If the skin-prick and blood tests are not conclusive, the doctor (allergist) may order a food challenge (oral) where emergency medications and emergency equipment are on standby. Under the strict supervision of an allergist, the client is fed with tiny amounts of the suspected allergy-causing food in increasing doses.

Elimination diet

An elimination diet is also recommended by the doctor if he is unsure that peanuts are the ones causing the symptom or if the client has more than one type of food allergy.  The client will be asked to exclude peanuts or other suspected foods in his diet for a week or two then gradually include those foods again in the food regimen. This will help determine what specific food the client is allergic into. But this method cannot be safely used if the client has had severe food reaction before.


If the symptoms appear and you suspect that nuts or peanut products cause it, avoid exposure to it until your appointment to the doctor.  But if the allergic reaction is severe, immediately seek medical help.

There is no absolute treatment yet for nut or peanut allergy but the oral desensitization or oral immunotherapy (not yet approved by FDA), is still being used especially in children who are sensitive and allergic to peanuts. A new research has suggested that desensitizing children as early four to 11 months can be very effective in preventing tree nut or peanut allergy but it should be with precaution since the risk for anaphylaxis can happen if done incorrectly.

People with allergies have an epinephrine autoinjector (Auvi-Q, EpiPen) which they should carry along with them. This device has a single dose of medication and is being injected into the thigh.

When the doctor has ordered an epinephrine autoinjector, be sure you know how to operate it and so with your family members closest to you. This should also be carried with you at all times even if you’re at work or in school.

Have an extra auto-injector at work or in your car. You should also ask your doctor to prescribe a backup epinephrine auto-injector as spare in case you misplaced it. Do replace this before expiration date since an out-of-date epinephrine may not work properly.
Lastly, know when to use it by asking your doctor how to determine when you need a shot.

Lifestyle Modification and Home Precautions and Remedies

Read the labels on manufactured foods since the manufacturer is required to state whether the food contains or doesn’t contain peanuts. Nuts or peanuts may be incorporated in foods so never assume that they don’t contain such even if you think you know what’s in the food, still check the label and ingredients.

Here are some foods that contain nuts or peanuts and avoiding these can be a challenge.

  • Cookies and pastries
  • Cereals
  • Mixed nuts
  • Frozen desserts like ice cream
  • Grain Breads
  • Energy bars
  • Granola
  • Candies which have nuts
  • Nougat
  • Salad dressings
  • Arachis oil or peanut oil
  • Almond butter (and other butter containing other nuts)
  • Sunflower seeds
  • Ethnic dishes ( African, Indonesian, Chinese, Mexican, Vietnamese, Thai)
  • Avoid all products that could contain even a small amount or trace of peanuts and do not disregard a label that says the food was produced in a factory that processes peanuts.
  • If you are troubled during social gatherings because of the notion that you might accidentally eat peanuts or other foods you are allergic into, do not attempt to try it. If you are in doubt, politely refuse it.
  • Carry emergency medications like the auto-injector all the time. Be sure as a caregiver, you know how to use it.
  • Keep your child, who has an allergy to peanut, safe all the time by getting support from relatives, teachers, babysitters or caregivers. Teach them how to recognize the warning signs or symptoms of an allergic reaction and that the dangers it pose if not treated immediately. Also, teach your child how to ask help if she experiences those allergic reactions.

Have a list of the steps on what to do if there’s an allergic reaction like how to administer the prescribed medications and give a copy of this plan to the teacher, health care providers and also your family members.

Because of the children’s nature of being playful, sometimes they forget that they have an allergy to food especially when they are with their playmates or classmates. Do not allow your child to share foods and teach him not to eat foods from others.

Teachers or the staff in school should have a food allergy management plan and they should be trained in using the autoinjector.

To ensure that your child is receiving the right treatment when she or he is not able to communicate because of the allergic reaction, have him/her wear a medical alert bracelet or necklace where his/her name is written and the type of food allergy he/she has.