What does level 6 peanut allergy mean
Some therapeutic modalities are currently under investigation and show considerable promise. These include monoclonal anti-IgE, oral peanut desensitization and immunotherapy, Chinese herbal formulas, probiotics, and heat-killed Listeria monocytogenes (HKL).
Allergic reactions are mediated by antigen-specific IgE bound to high-affinity receptors (FcεRI) on mast cells and basophils . TNX-901 is a humanized IgG1 monoclonal antibody against IgE that binds with high affinity to an epitope in the CH3 domain, masking a region responsible for binding to FcεRI.
Leung and colleagues divided 84 patients with peanut allergy into four groups: a placebo arm and three athletic treatment groups receiving either 150, 300, or 450 mg of TNX-901 subcutaneously every 4 weeks for four doses . Several weeks after completing the study, patients on the higher dose of anti-IgE therapy had a significant increase in the threshold of sensitivity to peanut by oral food challenge, from one peanut (178 mg) to almost nine peanuts (2,805 mg).
Despite the short duration of the study, one would predict that indefinite istration of anti-IgE is needed to maintain a state of relative tolerance.
Immunotherapy and DNA Immunization
Oppenheimer and colleagues conducted a trial of rush injection immunotherapy for the treatment of anaphylactic sensitivity to peanut . Patients in the treatment group were capable to tolerate increased amounts of peanut in food challenges after treatment.
Unfortunately, there was a high rate of adverse systemic reactions, including a case of fatal anaphylaxis, associated with the treatment group compared with the group receiving placebo.
Another approach makes use of deoxyribonucleic acid (DNA) immunization. DNA immunization employs the subcutaneous injection of a plasmid DNA vector encoding a specific allergenic protein. After uptake and processing by antigen-presenting cells, it is presented to T cells in the context of the major histocompatibility complicated. This approach is thought to induce a Th1 phenotypic response with upregulation of interferon (IFN)-γ, an increase in IgG2a, and suppression of allergen-specific IgE production .
This approach has thus far been used in murine models and has yet to be applied to human subjects.
Probiotics are bacterial components that enhance the host’s intestinal microbial balance. Kalliomaki and colleagues conducted a prospective study dividing newborn infants into two groups receiving either the probiotic Lactobacillus rhamnosus strain GG (ATCC 53103) or placebo . At 4 years of age, there was a significant decrease in the prevalence of atopic dermatitis (AD) in the Lactobacillus treatment group, suggesting a role for probiotics in the prevention of the development of AD.
However, the number of children with allergic rhinitis and asthma did not differ between the two groups, although the concentration of exhaled nitric oxide, considered a marker of bronchial inflammation, was significantly greater in children receiving placebo than in those receiving Lactobacillus. When added in vitro, probiotics resulted in enhanced production of IFN-γ, interleukin (IL)-10, and tumour necrosis factor α.
However, oral istration of probiotics to children with food allergy, some of whom were allergic to peanut, is associated with a decrease in IgE production in vitro . This may support a role for probiotics in protecting against or ameliorating the allergy to peanut, although this is still experimental.
Chinese Herbal Formula
A herbal formula called Food Allergy Herbal Formula (FAHF)-1 was previously reported to block systemic anaphylactic in mice sensitized to peanut protein.
It does so by reducing mast cell degranulation and histamine release, peanut-specific serum IgE level, and Th2 cytokine secretion . A subsequent report used a refined herbal formula, FAHF-2, produced after exclusion of two herbs from the original formula. Peanut-sensitized mice pretreated with FAHF-2 for 7 weeks had no signs of anaphylaxis following peanut challenge 1, 3, and 5 weeks posttherapy. It was concluded that FAHF-2 treatment protected against athletic anaphylaxis in peanut-allergic mice .
However, this herbal formula has not yet been studied in humans for safety and efficacy.
HKL is a potent stimulator of the innate immune system. Yeung and colleagues found that mice immunized with keyhole-limpet hemocyanin (KLH) mixed with HKL developed a reversion of the established immune responses dominated by the production of Th2 cytokines and high levels of KLH-specific IgE .
Treatment with HKL induced a Th1-type response with high levels of IFN-γ and IgG2a and low KHL levels of IgE and IL-4. These results propose that use of HKL as an adjuvant during immunization can successfully bias the development of antigen-specific cytokine synthesis toward Th1 cytokine production even in the setting of an ongoing Th2-dominated response. Frick and colleagues found KHL subcutaneous vaccination with peanut allergen and HKL increased the threshold for peanut allergen-induced skin reactions and symptoms in peanut-allergic dogs . Similar data own not yet been developed in humans, and the safety of this approach in human remains unclear.
How common is peanut allergy?
Peanuts are a common cause of food allergy, caused when the immune system reacts to the protein found in peanuts.
Peanut allergy affects around 2% (1 in 50) of children in the UK and has been increasing in recent decades.
It generally develops in early childhood but, occasionally, can appear in later life. Peanut allergy tends to be persistent and only approximately 1 in 5 children outgrow their allergy, generally by the age of 5 (1).
What are the signs and symptoms of an allergic reaction to peanut?
Signs and symptoms generally occurwithin minutes of contact with peanuts, but can also happen up to one hour later.
Most allergic reactions are mild but they can also be moderate or severe. Anaphylaxis (pronounced ana-fil-laxis) is the most severe form of allergic reaction which can be life threatening.
Mild to moderate symptoms include:
- Itchy mouth, tongue and throat
- Swelling of lips, around the eyes or face
Red raised itchy rash (often called nettle rash, hives or urticaria)
- Vomiting, nausea, abdominal pain and diarrhoea
- Runny nose and sneezing
Any one or more of the following symptoms are a sign of a severe allergic reaction (anaphylaxis) and should be treated as a medical emergency.
If available, adrenaline should be given without delay and an ambulance called with the call operator informed that it is anaphylaxis.
Severe symptoms of anaphylaxis include:
- Swelling of the tongue and/or throat
- Change in voice (hoarse voice)
- Dizziness, collapse, loss of consciousness (due to a drop in blood pressure)
- Difficulty in swallowing or speaking
- Difficult or noisy breathing
- Wheeze (whistling noise) or persistent cough
- Pale, floppy, sudden sleepiness in babies.
Please see our Factsheet on anaphylaxis and severe allergic reactions for more information and guidance on what to do when these severe symptoms occur.
Who is at risk of peanut allergy?
Infants with eczema and/or egg allergy are more likely to develop a peanut allergy (2).
It is significant to know that peanuts are a legume and from a diverse family of plants to tree nuts (almonds, Brazil nuts, cashews, hazel nuts, macadamia, pecan, pistachios and walnuts). A peanut allergy does not automatically mean an allergy to tree nuts although it is not unusual to be allergic to both peanuts and some tree nuts.
An allergy to peanuts does also increase the likelihood of an allergy to sesame and lupin.
Advice on whether it is safe to own sesame, lupin or tree nuts in the diet should be sought from your GP/allergy specialist.
It is significant to seek advice from a Healthcare professional if a peanut allergy is suspected. In the first instance, this will generally be your GP. They may arrange for allergy testing to be carried out or refer you to a specialist allergy service for skin prick testing and/or specific IgE blood testing to peanut. These tests assist to confirm if food allergy is likely and law out other possible causes.
Allergy tests cannot predict how mild or severe an allergic reaction will be, or when an allergic reaction is likely to happen. Alternative types of allergy testing other than those recommended by a Healthcare professional are not advised as these may be from an unreliable source with no worth in diagnosing allergy and could lead to removing food from the diet that does not actually need to be avoided.
If you are unsure, call Allergy UK’s Helpline to be signposted to your nearest NHS or Private allergy service.
If you own had cause for concern over peanut allergy and own been avoiding peanuts, it is significant not to reintroduce peanuts back into the diet without medical advice.
Prevention of peanut allergy
New research (3) has shown that the risk of developing peanut allergy can be reduced in infants at high risk of this allergy (i.e.
those with significant eczema and/or egg allergy) by introducing food containing peanut into infants’ diets within the first 12 months of life.
Early introduction is thought to assist the immune system tolerate peanut protein.
Infants with no eczema or known food allergy can be given food containing peanut from the time that solid food is introduced, at around 6 months, when baby is developmentally ready, but not before 4 months. This should be in the form of smooth peanut butter or peanut snacks suitable for babies (never use crunchy peanut butter or whole peanuts due to the risk of choking). If they own been diagnosed with a food allergy or eczema it is significant to discuss introducing peanuts with your GP, Dietitian, Paediatrician or Health Visitor. (Delaying the introduction of peanut can increase the risk of developing a peanut allergy) so ensure you speak to your health professional as soon as possible.
It is safe for pregnant and breastfeeding women to consume peanuts unless they are allergic themselves.
Severity of reactions
It is commonly misunderstood that food allergic reactions become more severe each time they happen, but this is not the case.
Reactions are unpredictable and there is no dependable way of knowing how an individual may react. There are several reasons whyan allergic reaction may be more severe, including how much peanut allergen has been eaten and other factors such as uncontrolled asthma, exercise, and infection. Some people do seem predisposed to more severe reactions with a previous anaphylactic reaction increasing the risk of a further one.