Latest Allergy News

Allergy Prevention - an update

Preventing allergies in infancy is currently a major focus for allergy specialists and new information is emerging all the time. The following updated recommendations are based on the most recent ASCIA Guidelines on Infant feeding and allergy prevention (who based their guideline on a consensus agreement by participants in the Infant Feeding Summit hosted by the Centre for Food & Allergy Research (CFAR)) in May 2016.  They are now widely accepted as sensible, prudent measures to take if you have any allergies in your family.

What is an allergy?

An allergy occurs when the body's immune system over-reacts to normally harmless substances, which may be in the air or water, or things we touch or eat. When an allergic person comes in contact with such a substance their immune system produces a special kind of antibody (IgE) and other cells release further chemicals (histamines). This causes the symptoms of an allergic reaction.

What makes a baby susceptible to allergies?

Although infants with a family history of allergic diseases are at higher risk of allergies, infants with no family history can also develop allergies.

Your baby may inherit the tendency to develop allergies, if you, your partner, or any of your family suffers from eczema, asthma, hayfever or hives, allergic rhinitis, persistent cough, constant runny nose, food allergies (especially allergy to dairy, eggs, wheat, soy, peanuts, nuts, fish and shellfish), or recurrent ear infections.

Even if neither parent is allergic, there is still a 5-15% chance of a child developing allergies. For a child with one allergic parent the risk goes up to 25%, and if both parents are affected, there is a 50-60% chance of developing allergies. When both parents have the same allergic disease the risk increases to as high as 80%. The first child in the family is more at risk.

What the child inherits is the tendency to develop an allergy or allergies, not the specific hypersensitivity of any family member to specific allergenic factors. For example, if a parent has an allergy to shellfish the child will inherit the chance of being allergic, but not the specific shellfish allergy. The infant is born with the capacity to become sensitised to some allergen at some time. The stronger the family history of allergy, the greater the risk and the earlier the infant is likely to show symptoms.

The likelihood that a child will develop an allergy depends on both genetic and environmental factors. Children must be exposed to a potential allergen to become sensitised. Once this sensitivity is established, it can take very little contact with the allergen to cause a reaction and the child is also at risk of becoming allergic to other allergens.

If your infant already has an allergic disease (such as severe eczema or food allergy) you should discuss what specific steps might be useful with you doctor. These guidelines are relevant for all families, including those in which siblings or parents already have food allergies or other allergic conditions.  There are some simple but very important steps you can take to, either prevent the development of allergies or at least reduce the potential severity of reactions.

How can I prevent my child from developing allergies?

During pregnancy

Genetic factors are givens and out of your control. However, you do have some control over the exposure your baby has to allergens that can set off allergies in a child who is more likely to suffer from these conditions because of his or her genetic programming.

ASCIA recommends a healthy balanced diet, rich in fibre, vegetables, and fruit, to provide the many health benefits to the mother and infant during pregnancy and breastfeeding.

Exclusion of any particular foods (including foods considered to be highly allergenic like peanut) from the maternal diet during pregnancy or breastfeeding is not recommended, as this has not been shown to prevent allergies.

Up to 3 servings of oily fish per week may be beneficial, as there is evidence that omega-3 fatty acids (found in oily fish) during pregnancy and breastfeeding may help to prevent eczema in early life.

The advice on probiotics supplements cannot be made currently, because the optimal species and dose of probiotic that might have an effect is unclear. However, some of the studies look promising that probiotics during pregnancy and breastfeeding may help prevent eczema in early life.

While breastfeeding

It is very clear that sensitisation continues during breastfeeding and that significant amounts of allergens pass through the breastmilk causing allergic symptoms in babies. Infants born into a family with a history of allergy should be breastfed exclusively, if possible, for a minimum of six months.

Several studies have shown that breastfeeding helps to reduce the odds of developing an allergy when compared to feeding with standard milk or soy based formulas. However, this advantage is dependent on your diet. The same issues and preventative measures apply as in pregnancy, but again it is important, that in avoiding allergens you don't compromise your own diet.

There is low evidence that breastfeeding during the period that solids are first introduced to infants from around 6 months may help reduce the risk of the infant developing allergies.   If breastfeeding is not possible or if a supplement to breastmilk is desired, use a a standard cow’s milk based formula). There is no evidence that soy or goat's  formula reduce the risk of allergic disease.

There is no consistent convincing evidence to support a protective role for partially hydrolysed formulas (usually labelled  ‘HA’ or Hypoallergenic.  Or extensively hydrolysed formula for the prevention of eczema, food allergy, asthma, or allergic rhinitis in infants or children.

Regular cow’s, goat’s milk, soy milk, nut and cereal beverages are not recommended for infants as the main source of milk before 12 months of age.

Introducing solids

Foods should not be introduced before 4 months

·     Infants differ in the age that they are developmentally ready for solid foods

·    Signs that your infant may be ready to start solid foods include being able to sit  relatively unaided and trying to reach out and grab food

ASCIA recommends the introduction of solid foods around 6 months, but not before 4 months, and preferably while breastfeeding

When the infant is ready, introduce solids according to what the family usually eats, regardless of whether the food is considered to be a common allergen.

·   Common allergenic foods like peanut, nuts, wheat and fish should not be delayed

·    Avoid raw eggs

Introduce one new food at a time, so that if a reaction occurs, the problem food can be easily identified.

Cow’s milk or soy milk and their products can be used in cooking if they are tolerated

There is good evidence that for infants with severe eczema and/or egg allergy, that regular peanut intake before 12 months of age can reduce the risk of developing peanut allergy

There is moderate evidence that introducing cooked egg into an infant diet before 8 months of age, where there is a family history of allergy, can reduce the risk of developing the risk of egg allergy.

Facial skin of babies is very sensitive and many irritant foods like citrus, tomatoes, berries, other fruits and vegemite can irritate the skin on contact, causing redness. However, this is not an allergy.

Some infants will develop food allergies regardless of what you do. If there is any allergic reaction to a food, that food should be stopped immediately, and you should seek advice from a doctor with experience in food allergy

General precautions

If your baby is at risk of developing an allergy, avoid using massage oil or nipple cream containing peanut oil, and make sure that the nappy rash products you use are also free from this ingredient. Using these products can sensitise your baby.

Try to minimize the exposure to inhalant allergens as well, such as cigarette smoke, polluted air, strong odours, animal fur, feathers, and dust mites.

If you smoke, stop! There is strong scientific evidence that exposure to cigarette smoke can contribute to the development of asthma and allergic disease.

   If you smoke, stop! There is strong scientific evidence that exposure to cigarette smoke can contribute to the development of asthma and allergic disease

What are the early warning signs of allergy?

Parents should look for early signs of sensitivity such as:

   Colic (not exclusively caused by allergy but can be an allergic symptom), excessive vomiting, abdominal pain, diarrhoea or constipation

   Skin rashes and eczema

   Swelling or welts

   Persistent sniffling and wheezing, stuffy nose, frequent colds, recurring ear infections

An unexplained change of behaviour as well as difficulties in breastfeeding or refusal of food.


Previous Allergy News
Immunotherapy: The past, present & future of allergy treatment

The role of the immune system is to protect the body from harmful foreign substances. The immune system has 2 different modes of attack based on the invader. Th1 (T Helper 1) lymphocytes goes after invaders that get into our cells, cell mediated immunity. The other the Th2 (T Helper2) lymphocytes attack extracellular invaders that are outside the cell, in blood and other body fluids, antibody-mediated immunity. The atopic or allergic individual has an imbalance in their immunity towards the Th2 immune response. The immune response is orchestrated via the T lymphocytes and with the help of antibodies. There are several classes of antibodies including IgG, which are useful in fighting bacterial infections. The IgE class of antibodies is involved in allergic reactions and also some parasitic infections. An allergic reaction is caused by the fact that the immune system of the allergic individual is malfunctioning and is over-reacting to a supposed foreign invader protein. The allergic individual produces an excessive amount of IgE antibodies against the substances that they are allergic to. IgE antibodies respond to allergenic proteins by causing the release of histamine and other allergic mediators. The concept of immunotherapy is to retrain the immune system to tolerate these allergens. Allergen-specific immunotherapy involves the administration of gradually increasing quantities of an allergen product to an individual with IgE-mediated allergic diseases, in order to achieve tolerance of those allergens that cause symptoms. Immunotherapy will only work for IgE-mediated diseases, and this is the main reason why IgE antibodies have to be identified to the specific allergen either in the blood (Specific IgE, RAST-type blood tests) or in the skin through skin prick tests, before immunotherapy can be considered.

The efficacy of immunotherapy was confirmed 100 years ago, and even though the basic principle of immunotherapy has not changed, the mechanisms responsible for its efficacy are still being worked out. On the whole, immunotherapy causes "immune deviation", from the typical "Th2" predominant lymphocyte subset seen in allergies to the "Th1" predominant subset. Immunotherapy leads to a reduction in the number of allergen specific IgE antibodies and increases the allergen specific IgG (considered blocking antibodies) antibody levels. There is a blunting of seasonal increase in pollen specific IgE in patients with hay fever. There is also inhibition of the recruitment and activation of other immune cells including mast cells, and eosinophils.

The most popular immunotherapy protocol in New Zealand involves weekly injections (under the skin) of gradually increasing doses of the allergen over a 12 week interval, up to a maintenance dose, which is then injected monthly for three to five years. Most patients will see some improvement in their symptoms within six months, but the 3-5 year length of the program is necessary to achieve the long-lasting effect, which persists long after the treatment is stopped.

Treatment options for allergies

A carefully taken history guides the physician to the appropriate allergy tests (skin prick tests, specific IgE (RAST-type) blood tests, and allergen challenges) in order to confirm the trigger/s for the allergic disease. Once the specific trigger/s are identified the options for management of the allergic disease includes - usually in a step-wise or pyramid manner - allergen avoidance (when this possible), drug therapy, including antihistamines, steroids, and more powerful immunosuppressive drugs like cyclosporine.

Traditionally immunotherapy has usually been the last choice on the list. For reasons which will be discussed later this position has recently been challenged. The main advantage of immunotherapy over the 'symptomatic' drug therapy is the fact that immunotherapy alters the patient's immune response to the allergenic trigger rather than just suppressing the symptoms. Therefore after the end of a course of immunotherapy when the treatment stops the patient continues to be symptom-free when the allergen is encountered, instead of the symptoms recurring when drug therapy (antihistamines, steroids & immunosuppressives) is stopped.

What allergies can be treated with immunotherapy & why?

The efficacy of subcutaneous (injection under the skin) immunotherapy was first established just over a century ago by the pioneers Noon & Freedman, who first described successful treatment of grass pollen-induced hay fever with grass pollen inoculations. Noon believed that the pollen 'toxin' was the cause of hay fever and was able to demonstrate effective treatment of hay fever patients with a protocol of increasing doses of grass pollen extract injected under the skin. He also established that anaphylaxis could be caused by subcutaneous immunotherapy if the dose is too high. This study done even back then showed that the clinical benefits may persist for at least 1 year after stopping the treatment.

In 2007 Caledron et al published the first Cochrane systematic review and meta-analysis evaluating the effect of immunotherapy on seasonal allergic rhinitis (hay fever). Fifty-one randomised controlled trials published between 1984 and 2006 were included. There were a total of 2871 patients: 1645 active and 1226 placebo. There was significant improvement in symptoms score and medication score in the actively treated groups. The clinical efficacy of immunotherapy in asthma was evaluated by Abramson and colleagues in 3 systematic reviews and meta-analysis. This meta-analysis showed significant reduction in asthma symptoms and medication and improvement in bronchial hyper-reactivity following immunotherapy.

Immunotherapy to insect venoms has been shown to be most effective in the prevention of future anaphylaxis to insect stings in individuals who were previously susceptible. Ross et al conducted and published meta-analysis in 2000, looking at the effect of immunotherapy in treating venom anaphylaxis. Eight studies published between 1966 and 1996 were included. The authors found that symptoms of venom hypersensitivity were prevented in 79% of the 101 patients receiving immunotherapy versus 36% of the comparison patients.

There are also several studies showing efficacy of aeroallergen immunotherapy (mainly dust mites) in treating atopic eczema. In 2012 Darsow reviewed Allergen specific Immunotherapy for Atopic Eczema and noted that patients with house dust mite sensitisation have been studied extensively, and found that better effects are seen in patients with severe eczema. Some studies have also shown benefit of birch and grass pollen immunotherapy in eczema.

At the present time the efficacy & safety of immunotherapy for the treatment of food allergy is investigational.

Other reasons why allergen immunotherapy is better than drug therapy for treating allergies?

  • It stops the allergic march by modifying the course of the allergic disease by reducing the risk of new allergic sensitization and inhibits the development of clinical asthma in children treated for allergic rhinitis. In 1997 Des Roches et al demonstrated that immunotherapy may prevent new sensitisations and in 2002 Moller et al demonstrated that immunotherapy may prevent progression of allergic rhinitis and asthma in children.
  • Long-lasting effects: existing data suggest that immunotherapy achieves long lasting relief of allergic symptoms, unlike the benefit of drugs which only last as long as they are continued. In 2007 Jacobsen et al showed that the asthma preventative effect of immunotherapy was still significant 7 years after the treatment discontinuation.
  • Cost-effectiveness of immunotherapy: A review study by Betro published in 2008 looking at immunotherapy in comparison to standard pharmaceutical treatment, have shown that immunotherapy may be very beneficial to the healthcare systems, in that either it could bring more clinical outcome at a reduced cost, versus standard therapy alone, or it could bring extra benefit at a very acceptable extra cost. This is even more attractive when indirect costs of lost productivity are considered & included in the economic analysis

Sublingual Immunotherapy

Since allergen immunotherapy was first described 100 years ago, it has traditionally been given by injections. The main draw backs to injection immunotherapy is the inconvenience, in that it has to be given in a doctor's office, and the patients wait for 30 minutes after the injection to observe for reactions to the injection.

All the studies on allergen immunotherapy over the years have shown that the efficacy of immunotherapy is dose-dependent. Oral or sublingual immunotherapy even though safer than injection needs a much higher dose than injection as the absorption is much reduced via this route. This is the reason why earlier studies of sublingual immunotherapy were no better than placebo. More recent blinded, placebo-controlled sublingual immunotherapy studies, with much higher doses have shown efficacy. Most studies done comparing injection immunotherapy with sublingual show that sublingual is inferior to injection as far as efficacy, but much safer.

A very recent meta-analysis on sublingual immunotherapy done by Lin et al concluded that the overall evidence provides a moderate grade level of evidence to support the effectiveness of sublingual immunotherapy for the treatment of allergic rhinitis and asthma, but high quality studies are still needed to answer questions regarding optimal dosing strategies. There were also limitations in the standardization of adverse event reporting, but no life-threatening events were noted in the review. At the present time in New Zealand, the cost of sublingual immunotherapy -along with the inferior efficacy- does not make it an attractive alternative to injection immunotherapy.

Practical advice on immunotherapy

If you suffer from severe hay fever, asthma, eczema or have had any reactions to bee or wasp sting apart from local reactions, ask your doctor about immunotherapy.

Conclusion

Allergen immunotherapy is one of the oldest treatments for allergies. It has lasted 100 years and unlike other treatment for allergies it treats the cause of the problem and not just the symptoms, and the effects persists long after the treatment is discontinued. It has also been shown to prevent allergies in children and stop the progression of allergies, the "allergic march". Also over the years the side effects, including anaphylaxis are improving as the allergen extracts (vaccines) and the methods for administering the vaccines have improved. Allergen immunotherapy is an allergy treatment of the past, present and future.

References

Abramson MJ, Puy RM, Weiner JM. Is allergen immunotherapy effective in asthma? A meta-analysis of randomized controlled trials. Am J. Respir. Crit. Care Med 151 (4), 969-974 (1995)
Abramson Mj et al. Allergen immunotherapy for asthma. Cochrane Database Syst. Rev. 4 CD001186 (2003)
Betro, Patrizia et al. Economic study of immunotherapy: A review. Current Opinion in Allergy & Clin Immunol. Dec 2008: Vol 8: issue 6: 585-589
Calderon MA, Alves B, Jacobson M et al. Allergen injection immunotherapy for seasonal allergic rhinitis. Cochrane Database Syst Rev 1, CD001936 (2007)
Darsow U. Allergen-specific immunotherapy for atopic eczema Curr Opin Allergy Clin Immunol. 2012; 12 (6): 665-669
Des Roches A, Paradis L, Menardo J et al. Immunotherapy with standardized house dust mite extract prevents the onset of new sensitisation in children. J Allergy Clin Immunol. 99 (4), 450-453 (2004)
Jacobsen L, Niggemann B, Dreborg S et al. Specific immunotherapy has long-term preventative effect on seasonal and perennial asthma: 10 year follow-up on the PAT study. Allergy 62 (8), 943-948 (2007)
Johnstone DE. Study of the role of antigen dosage in the treatment of pollenosis and pollen asthma. J Dis Child. 94 (1), 1-5 91957)
Johnstone DE, Dutton A. The value of hyposensitisation therapy in bronchial asthma in children - a 14 year study. Pediatrics 42;b793-802 (1968)
Lin SY et al. Sublingual immunotherapy for treatment of allergic rhinoconjunctivitis and asthma: A systematic review. JAMA 2013: 309 (12): 1278-1288
Moller C, DreborgvS, Ferdousibet al. Pollen immunotherapy reduces development of asthma in children with seasonal rhinoconjunctivitis (the PAT study) J Allergy Clin Immunol 109 (20, 251-256 (2002)
Novak N. Allergen specific immunotherapy for atopic dermatitis. Curr Opin Allergy Clin Immunol 2007; 7: 542-546
Ring J & Gutermuth J, 100 years of hyposensitisation history of allergen-specific immunotherapy (ASIT), Allergy 2011; 66: 713-724
Ross RN, Nelson HS, Finegold I. Effectiveness of specific immunotherapy in the treatment of Hymenoptera venom hypersensitivity: a meta-analysis. Clin. Ther22 (3)351-358 (2000)
Werfel T, Breuer K et al. Usefulness of specific immunotherapy in patients with atopic dermatitis and allergic sensitization to house dust mites: a multi-center, randomized, dose-response study. Allergy 2006;61: 202-205