Health Professional Quality Answers on Food Allergies

Pulse is a UK site intended for health professionals only. That's code for saying that they use medical terms and expect their readers to understand them.

That's okay. The answers are pretty straightforward, and most people with food allergies have already encountered these terms over the years.

The current topic is Key questions on food allergies. "Allergy GPSI Dr Adrian Morris answers GP Dr Mandy Fry’s questions on diagnosing cow’s milk allergy, prescribing Epipens and the value of allergen avoidance in pregnancy."

Here are some excerpts that are of concern to those with dairy allergies.

2. How can you confirm a diagnosis of cow’s milk allergy?

Cow’s milk allergy is relatively common in infants (1:50) and rarely develops after one year of age. Symptom improvement on a cow’s milk-free diet and recurrence of symptoms with reintroduction of cow’s milk formula is the most accurate diagnostic method.

Skin prick tests using fresh cow’s milk and RAST blood tests for cow’s milk protein IgE antibodies are the only reliable tests and have 60-90% accuracy. The higher the milk-specific IgE, the more likely there is to be a clinically relevant milk allergy. On the other hand, IgG antibody testing for cow’s milk proteins (casein and b-lactoglobulin) is of no diagnostic use.

The clinical history and observation of the infant feeding are very helpful, and a family history of atopy increases the likelihood of a food allergy. Cow’s milk allergy can manifest with immediate urticaria and facial angioedema and respiratory, oral and laryngeal symptoms, as well as deteriorating eczema in addition to typical symptoms such as vomiting, diarrhoea, persistent reflux, food refusal and even anaphylaxis in severe cases.

Mildly milk-allergic infants will tolerate small amounts of processed dairy produce such as yoghurt and cheese. Infants with severe cow’s milk allergy will react to traces of milk protein in partially hydrolysed formula, and even breast milk, as well as any skin contact.

3. What are the best formula alternatives and what role do other milks play?

Cow’s milk-free formulas are expensive - £8 to £20 per 400g. Amino acid-based formulas such as Neocate and Pepdite are best because they are completely free of cow’s milk protein, but are more expensive than extensively hydrolysed formulas such as Nutramigen and Pregestimil, which are the current preferred cow’s milk-free formulas. Exquisitely sensitive infants may react to traces of cow’s milk protein even in extensively hydrolysed formulae.

An amino acid-based formula provides a good therapeutic trial for initial diagnosis of cow’s milk allergy, after which it would be cheaper to switch to an extensively hydrolysed formula – if it can be tolerated.

Although soy milk is the cheapest alternative formula available at around £4 per 400g, 20% of cow’s milk allergic infants will develop a concomitant soy allergy. The fear that soy milk phyto-oestrogens can feminise male infants is without scientific foundation.

Goat’s milk is inappropriate as it contains many of the allergenic proteins found in cow’s milk, so should not be recommended. Comminuted chicken meat suspensions are another alternative, particularly if there is associated carbohydrate intolerance.

4. How many affected infants will grow out of a cow’s milk allergy?

Half will outgrow their cow’s milk allergy within one year, 75% by two years and 90% within three years. Cow’s milk protein intolerant infants with problematic gastro-oesophageal reflux and colic usually spontaneously recover by the end of the first year. This represents a delayed hypersensitivity to the cow’s milk protein resulting in oesophageal inflammation and eosinophilic infultrates. Depending on severity it makes sense to rechallenge cow’s milk allergic children after one year and then every six months thereafter. In severe cow’s milk allergy challenge testing should not be contemplated outside a hospital setting.

The rest of the article is way too long to repost, but contains a lot of good general information for parents of kids with food allergies. Please take the time to read it.