Just like some people have an allergic reaction to medicines, they can also have an allergic reaction to certain types of foods including nuts. The immune system overreacts when it comes in contact with the nuts or any other allergen. The allergic reaction from the nuts can be mild or severe. Anaphylaxis is a severe allergic reaction to nuts, which is a potentially life-threatening situation. Patient has symptoms usually within a few minutes or an hour after coming into contact with a nut.
Patient with nut allergy should always avoid nuts and foods that contain nuts to prevent an allergic reaction. However, if there is an allergic reaction after accidently coming in contact with the nuts, then treatment should be started immediately to decrease the risks. In severe allergic reaction, an adrenaline (epinephrine) injection should be given after which patient should be taken to a hospital. Prompt action and treatment of an allergic reaction to nuts helps in decreasing the risk of serious problems or complications.
What Causes Allergic Reaction to Nuts?
An allergic reaction occurs when the body's immune system overreacts to any substance (allergen). In most cases, allergens are not harmful and they do not have any effect on those individuals who are not allergic to them. Nut allergy can be mild to life-threatening. People can develop an allergic reaction to different types of allergens; however, nuts can cause some of the most severe and strongest allergic reactions. The exact cause of this is not clear.
Tree nuts (hazelnuts, walnuts, pecans, cashews, almonds, pistachios, brazils) as well as peanuts can act as allergens and produce an allergic reaction in some individuals. When a person comes into contact with the nuts, the mast cells in the body release histamine which causes the small blood vessels in the body to leak fluid. This fluid then causes swelling of the tissues producing an allergic reaction comprising of different symptoms. In some cases patient may not have any symptoms or allergic reaction the first time it comes in contact with nuts and will experience full allergic reaction only after coming into contact with nuts for the second time.
Most of the individuals having a nut allergy will develop an allergic reaction after coming in contact with only small amounts and some individuals can even develop an allergic reaction after coming in contact with only trace amounts of nuts. Some people are so sensitive to nuts that even a small amount on their lips, or if they are standing next to someone who is eating peanuts, will be enough to start an allergic reaction in them.
How Common is Nut Allergy and Who is More Susceptible to it?
Allergic reaction to nuts is the most common type of severe food allergy. Nut allergy usually starts when the children are very young, about between 14 months and two years old. People with an allergic reaction to nuts are unlikely to grow out of it. If a person suffers from atopy, or if there is a family history of atopy, then risk of developing a nut allergy increases. Allergy to peanuts also increases the risk of allergy to tree nuts.
What Happens When You Have an Allergic Reaction to Nuts?
The allergic reaction to nuts ranges from mild to very severe and can be potentially fatal. Symptoms usually develop within minutes to an hour after coming in contact with nuts. Reactions that develop after more than four hours of coming in contact with nuts are not likely to be an allergic reaction.
Mild allergic reactions to nuts include:
- Tingling sensation of the lips and mouth.
- Swelling of the face.
- Feeling of tightness around the throat.
- Feeling sick.
- Hives (urticaria) or nettle rash.
- Colicky pain in the abdomen.
A severe allergic reaction to nuts includes all of the above symptoms and more such as:
- Feeling of impending doom.
- Patient will have difficulty in breathing and wheezing due to swelling around the throat or an asthma type of attack.
- The blood vessels get dilated due to which the patient has:
- Skin redness.
- Rapid heart rate.
- Low blood pressure (hypotension) due to which patient can feel faint.
- Anaphylaxis is a severe reaction which needs immediate medical attention otherwise it can result in the death of the patient.
- A second allergic reaction to the nuts can develop about 2 to 8 hours after the initial allergic reaction. For this reason it is important that the patient continues to stay in hospital after the first allergic reaction to the nuts.
Diagnosis of Nut Allergy
Patient's medical history and physical exam are done. The patient is asked a lot of questions, such as the quantity and type of food consumed and how soon the symptoms started, the severity and duration of the symptoms.
Skin prick test is done to confirm allergy. Patient is instructed not to take antihistamines on the day of this test, as it can interfere or subdue any allergic response to the test. A drop of nut extract solution is applied to the patient's skin then a needle prick is made through this drop. This will cause a small amount of the solution to enter into the skin. Patients having an allergy to nuts will experience an allergic reaction within 20-30 minutes. When the skin under the drop becomes itchy and red, then the skin prick test is considered "positive." There also may be a raised, white colored swelling known as weal around the red area which takes about 15-20 minutes to reach its maximum size, and recedes over a few hours. If the skin remains normal then the skin prick test is considered to be "negative."
Blood Tests such as ELISA test or a RAST test can be done to measure IgE antibody, which is a protein produced as a result of an allergic reaction.
Food Challenge is done if the above tests are not definitive. Food challenges are always carried out at hospitals as it carries a great risk of a severe allergic reaction. Patient is given several types of foods which may or may not contain nuts. Patient is then closely observed for half-an-hour to look for an allergic reaction.
How to Treat an Allergic Reaction to Nuts?
After the nut allergy is confirmed, the allergy specialist helps the patient in devising a plan to manage the allergy. This plan will be customized according to patient and is also based upon the severity of the allergic reaction to nuts.
Prevention of an allergic reaction to the nuts is important for the patient. Patient should carefully check the foods and recognize those foods which may contain nuts, so he/she can avoid them. A dietician can help the patient in dealing with this. Antihistamine medicine is sufficient for mild allergic reaction to nuts.
Adrenaline (epinephrine) injection is given for severe allergic reaction to nuts. This injection is like a pen and should always be carried around by the patient. There are different doses of epinephrine for adults and children and it can be injected into the thigh muscle upon pressing a button or jabbing it against the skin. Two sets of injections can also be carried to be on the safe side. The expiry date of the adrenaline (epinephrine) injection should always be checked regularly.
In case of severe allergic reaction to the nuts, patient will be hospitalized where he/she is given supplemental oxygen to help with breathing. Steroids may also be given to reduce inflammation along with antihistamines to counter the allergic reaction. More intensive treatment is needed in patients with a severe allergic reaction to the nuts. Mild symptoms of the allergic reaction can be present for an hour; whereas severe symptoms can be present for a longer time. Patient should be kept in hospital till he/she is fully recovered.
How to Prevent an Allergic Reaction to Nuts?
The following instructions should be followed by the patient to prevent an allergic reaction to nuts:
- All type of nuts should be avoided.
- Always check the ingredients and check the food labels for nuts and patient should also get a list of nut-free foods from the grocery store.
- Patient should stop eating foods from delicatessens, bakeries, buffets as it is easier in these places for food to get contaminated through coming in contact with other foods that contain nuts.
- When eating out, patient should ask the staff regarding foods that contain nuts and specifically instruct them to prepare and serve food without any type of nut ingredient.
- Avoid anything, which you are not sure if it may or may not contain nuts.
- If others are preparing food for the patient then they should be informed about the nut allergy.
- It is important to be prepared for an allergic reaction to nuts, as one can accidentally come in contact with them.
- It is important that your friends and family members are made aware that you have a nut allergy and they know what should be done for an allergic reaction to nuts.
- You or anyone else suffering from nut allergy should wear a medical emergency identification bracelet or something equal to that.
Once a person has an allergic reaction to nuts the chances of having another one are very high, as it is impossible to avoid nuts all the time. Nut allergy can be a cause of stress; however, if the patient is well prepared and if immediate action is taken then risk of having any serious problems is less.