Date: 15 July 2014
Replay: You can watch or listen to the meeting here
Meeting Notes: The following notes were made for the meeting in response to questions asked by attendees.
Babies – Reflux and Allergy
75-80% of babies have regurgitation in the first year of life and this resolves by one year of age in 95%. Choking, gagging, coughing with feeds or irritability can indicate a more significant problem. Neurologic disorders, infections and cow’s milk protein allergy need to be excluded and cow’s milk allergy may co-exist with reflux in 40-60% of babies with reflux.
Allergy – Some Definitions
An IgE mediated allergy occurs when cells in the immune system have produced an E class antibody to a protein and when the antibody and protein come together, the combination of the two causes a release of histamine and other chemicals from cells in the body to cause the typical features of an allergic reaction – hives, swelling, nasal congestion, wheeze, abdominal pain (for food allergies where the reaction is occurring in the intestines) and in severe cases a drop in blood pressure and shock (anaphylaxis). This reaction occurs within minutes of contact / ingestion of the exposure to the allergen (the thing you are allergic to). There is then a late or second phase of this reaction where other cells of the immune system are activated and they cause a different kind of reaction with chronic inflammation and cells called eosinophils are found in the inflamed tissue. This is the indicator that allergy precipitated the inflammation. This kind of inflammation is responsible for atopic (allergic) dermatitis and eosinophilic oesophagitis among other problems.
Both of these reactions, the early and late reaction are caused by the immune system and while some people may exhibit both reactions – for example a baby will have an immediate reaction to cow’s milk or egg when exposed, but then the dermatitis will start to flare, often about 24 hours later and stay more active for several days. In some cases the immediate reaction may not occur but the child has a positive skin prick test or blood test and once a food is removed the dermatitis will calm significantly – although not be completely “cured” as food is not the only cause of the dermatitis. In eosinophilic oesophagitis, removal of only foods that give a positive result on a skin test or blood test only results in improvement in 40-60% of patients where a more arbitrary six food elimination diet, SFED gives 85-90% improvement rates. The six foods are cow’s milk, egg, soy, wheat, peanuts and tree nuts and fish/shellfish. When the foods are reintroduced milk causes a flare in 75%, wheat flares 26%, egg 17% and soy 10%.
An aside on testing. Skin prick tests work by introducing a small amount of various proteins (allergens) into the skin where the immune system can “see” them. If you have E-class (allergy) antibodies to the protein, the protein and the antibody attach and then trigger a receptor on a cell to release histamine, causing a red itchy welt – think of a key that is in two pieces – the antibody and the allergen – when the two are put together the key can unlock the cell to release the histamine – cause the allergy symptoms. An allergy blood test – called a RAST test involves putting a sample of the patient’s blood on a test slide that has the allergens being tested for in little wells. If there are antibodies in the blood they will attach to the allergens they are directed against and stay stuck together. The blood is rinsed away and a solution which attaches to the tails of the antibodies is then applied. That solution has a marker that can be counted. So for every antibody attached to the allergens in each well, there will be a marker to count – the more antibodies, the higher your score or result.
Allergy patch testing is an attempt, with foods at least, to look for evidence of a reaction by the cells in the immune system to the food. The food is placed on a band-aid type patch and left on for 48 hours. When removed the area is observed for any inflammation – like a patch of dermatitis. For eosinophilic it may be a complementary test to the skin prick testing, but more research needs to be done.
A food intolerance is a different reaction to food and in the case of intolerance we don’t know the exact pathway, that is, we can’t follow the exact steps to know what is happening between eating the food and the symptoms. The important thing with both food intolerances and food allergies is that they are reproducible – every time the food is given, the reaction will occur. Food intolerances cause food protein enterocolitis syndrome (FPIES), proctocolitis/proctitis (inflammation of the lower bowel). Redness around the anus can occur as a reaction to food as not all the food will be absorbed and thus “comes out the other end” causing inflammation of the skin and some of the inflammatory chemicals released as part of the allergic reaction can “come out the other end” causing inflammation.
In babies with gastroesophageal reflux, up to 40% have evidence of cow’s milk allergy but remember that cow’s milk allergy occurs in 2-3% of babies age 1 so it may be a case of two common things occurring together rather than one causing the other BUT removal of cow’s milk (from babies or mums diet) can improve reflux symptoms in 25-35% of babies. In babies with reflux and cow’s milk allergy the reflux is usually not the only symptom of the allergy – the baby will have dermatitis or may have diarrhoea with blood or mucous in the bowel motion.
The European and North American guidelines for reflux in infants suggest that if the baby is not distressed, then observation is the best option as it will often settle without treatment. Posturing the child (elevating the head off the bed) can help and sleeping bub on the tummy reduces reflux BUT increases the risk of SIDs so this is only acceptable once baby is over 12 months. If the baby has more persistent vomiting, poor weight gain and irritability, then a two week trial on an extensively hydrolysed formula or commercially thickened formula is warranted. Note that thickening a formula with rice cereal increases the calorie content by 50-75%. Also, it can take two weeks to see an improvement. In breastfed babies mum should exclude egg and milk from her diet and only if symptoms persist should anti-acid treatment be considered.
The role of allergy in reflux needs more study but there is evidence that consuming the food you are allergic too affects the contraction of the muscles in the intestine and makes reflux worse. In eosinophilic oesophagitis it is thought that the direct contact of the food with the oesophagus causes the inflammation.
An intolerance does not usually lead to allergy BUT if skin prick tests are done on very young babies (under 6 months as a general rule) false negatives can occur – put simply the immune system might be too immature to give a result on the skin test, even though it is mature enough to be causing or contributing to a clinical problem such as dermatitis. In these babies, repeat testing at 12-18 months might reveal that a previous negative is now positive, but the fact that there was an allergy type problem, usually dermatitis, indicates that we haven’t gone from intolerance to allergy, but rather a false negative to a positive. There is some concern that the use of acid suppressing treatment may cause people to develop food allergies and this is something that has been seen in adults so any treatment with acid suppressing drugs needs to be carefully monitored, and if not helping, then it should be stopped. Note here that studies show these medicines decrease the inflammation in the oesophagus from the reflux but the reflux of fluid/food from the stomach is still occurring so vomiting, gagging and choking episodes can still occur.
In the past, it was thought that 95% or more of cow’s milk allergic children grow out of their allergy by age 3. Better or more recent studies (in more recent studies, remember that allergy is now more common and may be behaving differently) show that only 60-70% grow out of their allergy by age 5 and, even those still allergic by age 12 can still grow out of their allergy by adulthood. Peanut and tree nut allergies are usually lifelong problems but remember that not every reaction on a skin test or blood test definitely needs allergy and an actual reaction to a food or a challenge with the food is needed to confirm the allergy. The lifelong allergies are the confirmed allergies. As cow’s milk intolerance is more difficult to study, there is nothing to measure, there really aren’t good studies on the chance of losing these intolerances.
In cow’s milk there are two main proteins that cause allergy, casein and whey. Whey is destroyed by heating and the cultures/bacteria in yoghurt so if your allergy is to the whey protein you will tolerate heated milk. In baking also, the milk is bound up with the other ingredients so may be hidden from the immune system – there are really no reliable tests for this and a very cautious challenge is the only way of determining if a child can safely eat baked goods with milk or heated milk. The rennet added to cheese can de-nature the casein protein so a cheese that is heated and has rennet added (cheddar and parmesan) can be tolerated by many cow’s milk allergic children. These foods are best tried when baby is over one year of age and is better able to say if the food is causing an itchy or uncomfortable mouth so it can be determined early if the child is reacting. A note here – food challenges have a waiting time in public hospital allergy clinics of more than 12-18 months. In private practice there is no item number to allow for the doctor to get paid for doing the challenge, the process takes 4-5 hours and the doctor needs to be there all the time and in my opinion, not distracted seeing other patients behind closed doors so reactions can be recognised early and treated promptly.
When an allergen is eaten it stays in the system a short time before being bound up with the antibodies, doing its “job” of causing the allergic reaction and then the “clean up department” of the immune system takes away and destroys these antibodies attached to their allergen (antibodies are a one-use-only ‘type of thing’ and your immune system has to replace them by making more – if you try to do a blood test or skin prick test too soon after a bad allergic reaction that used up lots of antibody you may get a false negative result – because there are no antibodies left to detect). The delayed part of the reaction can persist for several days and once triggered doesn’t need the food to still be there to grumble on for a while.
The most important symptom to detect intolerance is the fact that it is reproducible in all forms of the food – a mum who thought her child was allergic to potato because he always gags on his mashed potato but the child happily admitted they love hot chips was dealing with a fussy eater. But if you react in the same way every time a food is eaten, you have an intolerance – the important thing is to find out if you have an allergy that can cause a life threatening reaction, a problem like eosinophilic oesophagitis (EoE) or FPIES that can cause severe symptoms (FPIES) or have the potential of long term consequences (EoE). People with allergy usually have other allergy problems – dermatitis (and if dermatitis is associated with a food allergy it is usually more severe and difficult to control), wheezy episodes, allergy prone parents or siblings.
If babies have food allergies the food does not always have to be excluded from mum’s diet. Food proteins don’t always get transferred in breast milk and it is not reliable and predictable when it does get transferred – some days it will and sometimes it won’t, sometimes it happens at the next feed, sometimes it’s the next day. In babies with dermatitis the usual plan is remove the allergy causing foods from baby’s diet and treat the skin with appropriate creams – if you are fighting a losing battle treating the skin, then restricting mum’s diet may help. In reflux, whether to restrict mum’s diet again depends on the severity of the problem – always restrict in EoE for instance, wait and see how baby responds in FPIES, try restricting mums diet first in the breastfed reflux baby BUT if there is no improvement in babies symptoms, then mum should eat what she wants.
Interesting things learnt during research for this talk
In 2011, an ice-creamist in London’s Covent Garden sold an ice cream called baby gaga made from human breast milk. Each ice cream cost 14 pound (the donor was paid 15pound for 10oz) – the ice cream sold out the first day but then Westminster council removed it from sale as they felt it was not fit for human consumption.
Baby < 6months – breastfeeding is sufficient (if mum has normal iron stores). Formula fed babies formula must be supplemented with iron (all Australian ones are)
- 7-12 months- both breast and formula fed babies need an iron fortified cereal
- Babies up to 3 years – 7mg per day
- 4-8years of age – 10mg per day
- 9-13 years – 8mg per day
- Adolescent male needs 11mg per day
- Adolescent female needs 15mg per day
- A 150g steak contains about 5mg of iron. Two medium eggs provide about 4mg of iron so getting enough iron relies on iron fortified cereals, consume vitamin C with the food containing iron (salad with meat, fruit with breakfast) and be aware that caffeine (tea, coffee and cola drinks) prevent iron being absorbed and milk is not only low in iron but also binds to the iron making it difficult to absorb. A serve of Milo or Ovaltine contains 6mg of iron.