Allergy (and clinical immunology)

Allergy care has changed.
And in many ways, that is a good thing.

The old approach often looked like this:
↳ Avoid more and more things
↳ Blame every symptom on a positive test
↳ Wait until symptoms get bad
↳ Treat everyone the same
↳ Reach for short-term relief again and again
↳ Make a plan only after a reaction happens

That is not the direction we want to keep going.

Better allergy care is more precise.

It starts with the right question:
What is actually going on here?

Because sneezing, wheezing, eczema, hives, and food reactions are not all the same problem.
And they should not all be treated the same way.

The newer approach is more thoughtful:

1️⃣ Targeted avoidance
Avoid only confirmed triggers, not everything “just in case.”

2️⃣ History plus testing
A test alone does not diagnose allergy. Test results need context.

3️⃣ Earlier control of inflammation
For asthma, rhinitis, and eczema, the goal is not just to chase flares. It is to control disease earlier.

4️⃣ Personalized care
Rhinitis, asthma, eczema, food allergy, and hives each need their own strategy.

5️⃣ Long-term tools when needed
Sprays, inhalers, skin care, allergy shots, biologics, and food allergy planning all have a role in the right patient.

6️⃣ Prevention and action plans
Education matters. Follow-up matters. Knowing what to do in a reaction matters.

7️⃣ Early food introduction for babies
One of the biggest shifts has been infant feeding.

The old idea was to delay common allergenic foods like peanut and egg.

Now we know that, when babies are developmentally ready, early introduction of common allergenic foods can help lower food allergy risk, especially in the right setting and with the right guidance.

So the “new way” is not doing more for the sake of doing more.

It is doing the right thing, for the right condition, at the right time.

That means less fear.
Less guesswork.
And better care.

What change in allergy care do you think patients or even clinicians still misunderstand the most?

More peanuts in pregnancy ≠ less peanut allergy in babies.
A major new NEJM trial just tested this.

For years, families have asked whether eating more peanut during pregnancy could lower their baby’s risk of developing peanut allergy.

Now we have much better data.

A new randomized trial included more than 2,100 pregnancies in families at higher risk for allergic disease.

One group was asked to eat at least:
🥜 60 peanuts per week
🥚 6 eggs per week

They continued this during pregnancy and through the first 4 months after delivery while breastfeeding.

The comparison group ate substantially less peanut and egg.

At 1 year of age, the babies were evaluated for IgE-mediated peanut or egg allergy.
The result?

7.8% of babies in the high peanut-and-egg group developed peanut or egg allergy.
8.4% in the comparison group did.

That difference was not statistically significant.

So eating substantially more peanut and egg during pregnancy and breastfeeding did not prevent food allergy in the baby.

But here is the important part:

This does not mean peanut exposure does not matter.

The stronger evidence for prevention comes after the baby is born.

Early introduction of peanut into an infant’s diet, followed by regular ingestion, can reduce the risk of developing peanut allergy.

So the practical message for parents is:

👉 You generally do not need to avoid peanut or egg during pregnancy just to prevent allergy.

👉 Eating extra peanut during pregnancy has not been shown to prevent peanut allergy.

👉 Introducing allergenic foods at the right time during infancy still matters.

Food allergy prevention may be less about what mom eats during pregnancy and more about when the baby starts eating the food.

Were you ever told to eat more, or avoid, certain foods during pregnancy because of allergy risk?

🧬 Molecular Allergology: A New Way of Understanding Allergic Diseases

For many years, we simply referred to allergies as being caused by peanuts, peaches, house dust mites, shrimp, or latex. Today, thanks to molecular allergology, we know that it is not only the allergen source that matters, but, more importantly, the individual allergenic proteins it contains.

These proteins, known as molecular allergens, and particularly pan-allergens, explain why the same patient may react to several seemingly unrelated allergen sources. For example, allergy to house dust mites may be associated with reactions to crustaceans, latex allergy may be linked to reactions to certain fruits, and peanut allergy may share homologous proteins with other legumes or tree nuts.

The identification of these molecular allergens has profoundly transformed our understanding of allergic diseases. It now enables far more accurate diagnosis, improved assessment of the risk of severe allergic reactions, better interpretation of sensitization profiles, and truly personalized patient management.

This illustration, entitled “The Allergome Metropolis”, offers an original way of visualizing this complex network of cross-reactivity. Inspired by a metropolitan transit map, each line represents a family of pan-allergens, while each station represents a major molecular allergen, allowing clinicians, researchers, and students to instantly appreciate the molecular relationships between different allergen sources.

🔬 The future of allergology is molecular. Understanding allergenic proteins means understanding allergic diseases with a level of precision that was unimaginable just a few years ago.

How Pediatricians Created the US Peanut Allergy Epidemic

https://lnkd.in/gKGQyhnS

Your child tested positive for a food allergy.
But does that mean they are actually allergic?

Not necessarily.

This is one of the most common misunderstandings I see in my allergy clinic.

A positive skin prick test or blood IgE test does not automatically mean someone has a food allergy.

It means their immune system has made IgE antibodies that recognize the food.

But whether eating that food will cause a reaction is a different question.

Here are 4 things a positive food allergy test can mean:

1️⃣ TRUE FOOD ALLERGY

The test is positive AND the clinical history supports an allergic reaction.

For example:
A child develops hives, vomiting, or wheezing shortly after eating peanuts, and peanut testing is positive.

The history and test results fit together.

2️⃣ SENSITIZATION WITHOUT ALLERGY

This is where confusion often begins.

A child may test positive to milk, egg, or peanut but eat that food regularly without any symptoms.

That is called sensitization.

And sensitization does not always mean allergy.

👉 If someone regularly eats a food without problems, a positive test alone is generally not a reason to remove it from their diet.

3️⃣ CROSS-REACTIVITY

Sometimes, the immune system recognizes proteins that look similar.

For example:

Someone with birch pollen allergy may test positive to apple or carrot because these foods contain proteins similar to birch pollen.

Some people develop itching in the mouth when eating these foods, called pollen-food allergy syndrome.

Others may have positive tests without symptoms.

A positive result does not always mean a dangerous food allergy.

4️⃣ AN ALLERGY THAT MAY HAVE BEEN OUTGROWN

This is particularly important in children.

Some children outgrow milk, egg, wheat, or other food allergies over time.

But their allergy tests may remain positive even after they develop tolerance.

That is why we look at:
↳ Previous reactions
↳ Changes in skin test or specific IgE results over time
↳ Whether a supervised oral food challenge is appropriate

An oral food challenge, performed under medical supervision, is the gold standard for confirming whether someone can tolerate a food when the diagnosis remains uncertain.

Here is what I wish more parents knew:

A positive test does not tell us the whole story.

And a larger skin test or higher IgE level does not reliably predict how severe a future reaction will be.

Testing should be guided by the clinical history, not used as a broad screening tool without a clear reason.

Unnecessary food avoidance can affect nutrition, quality of life, and create significant anxiety for families.

Before eliminating a food based only on a test result, discuss it with an allergist.

If there is a history of a possible allergic reaction, do not try reintroducing the food at home without appropriate guidance.

We treat patients, not just positive test results.

Have you or your child ever been told to avoid a food based only on a positive allergy test?

Peanut allergy dropped 81%.
Not from a new drug. From a baby snack.

Here's how we found out.

Jewish children living in the UK had about 10 times higher rates of peanut allergy than Jewish children living in Israel.

The genetics were nearly identical.

The environment was not.

Many Israeli infants regularly ate Bamba, a peanut puff snack, during infancy.

That observation led to one of the most important food allergy studies ever performed.

The LEAP trial enrolled 640 infants at high risk for peanut allergy (severe eczema, egg allergy, or both).

Half were introduced to peanut between 4 and 11 months of age and kept eating about 6 grams of peanut protein a week until age 5. The other half avoided peanut completely.

The numbers at age 5:

↳ 17.2% of the avoidance group developed peanut allergy

↳ 3.2% of the consumption group developed peanut allergy

↳ An 81% relative risk reduction

It held up. LEAP-On followed the same kids after 12 months off peanut:
18.6% allergic in the avoidance group vs. 4.8% in the consumption group.

LEAP-Trio followed them into adolescence: 15.4% vs. 4.4%.

Younger siblings introduced to peanut early had an 18.3% sensitization rate, vs. 44.4% in siblings who weren't (a different outcome measure than clinical allergy).

For context: peanut allergy prevalence in Western countries had roughly doubled over the decade before LEAP, reaching 1.4% to 3.0% of children, during the era when avoidance was standard advice.

But LEAP teaches us something beyond peanut.

Culture matters.

Families around the world introduce peanut, sesame, lentils, yogurt, fermented foods, and tree nuts at very different ages, and that may shape how the developing immune system learns what is safe.

Separately, some population-level observations (different literature than LEAP) suggest children raised on minimally processed, legume- and fish-rich diets have lower food allergy rates in parts of Asia compared with Western populations. Associative, not causal.

That does not mean one food, or one country's diet, is the answer.

Food allergy is influenced by many factors.

↳ Genetics

↳ Early food introduction

↳ Eczema and skin barrier health

↳ The microbiome

↳ Vitamin D and other environmental exposures

↳ Diet diversity and food processing

Most likely, it's the combination that determines risk.

One observation from Israeli children eating Bamba changed how we feed infants around the world.

Sometimes the biggest advances in medicine begin with someone noticing that one community does things differently.

The next breakthrough may already be happening in someone's kitchen.

Have you noticed cultural food practices that you think medicine should study more closely?

Beyond Early Allergen Introduction: A New Paradigm for Pediatric Allergy Prevention 👶💡

​As healthcare professionals, we’ve long focused on the timing of introducing peanuts and eggs to prevent food allergies. But a new EAACI interest group report (2025),co-authored by leading experts in the field such as Carina Venter , Emilia Vassilopoulou , Berber Vlieg-Boerstra RD PhD , and Alexandra Santos, MD PhD ,reminds us that the quality of the entire diet matters just as much.

​The latest guidance emphasizes a holistic "Healthy Complementary Feeding" approach to support immune maturation and a diverse gut microbiome.

​Key Clinical Takeaways:
⏱️ Timing is Key (4-6 Months): Start complementary feeding around this window to meet increasing needs for iron and zinc and to utilize the "window of opportunity" for immune tolerance.

​🥦 Prioritize Diversity: Encourage a high variety of whole, nutrient-dense, and home-cooked plant-based foods (vegetables, legumes, grains).

​🐟 Nutrient Focus: Aim for diets rich in fiber, iron, zinc, and omega-3 fatty acids, while including fermented foods like natural yogurt.

​🚫 The "Whole Food" Advantage: Discourage over-reliance on ultra-processed commercial baby foods and pouches, which are often low in nutrients and may delay the development of oral motor skills.

​🥜 Allergen Integration: Continue the early and regular introduction of regional allergens (especially egg and peanut), particularly for high-risk infants with eczema.

​By shifting our focus from "avoidance" to "diverse inclusion," we can better support the development of a healthy immune system in our youngest patients.

​Reference: Vlieg-Boerstra B, et al. Pediatr Allergy Immunol. 2025;36:e70150.

A very low maintenance dose of #peanut #oral #immunotherapy significantly increased tolerated peanut exposure and improved immunologic markers compared with strict avoidance, achieving desensitisation similar to a high dose. https://lnkd.in/dfAtjB2Y

FOOD ALLERGY NEWS: Eating gradually increasing doses of store-bought, home-measured peanut butter for about 18 months in a clinical trial enabled 100% of…

We previously described safety of preschool peanut oral immunotherapy (P-OIT) in a
real-world setting; 0.4% of patients experienced a severe reaction, and 4.1% received
epinephrine, during build-up.