Few things are as frustrating as having to give up your favorite foods. But for a growing number of Americans developing severe allergies later in life, more and more are coming to terms with that new reality.
It’s not just food. Seasonal allergies are also surging, with Centers for Disease Control and Prevention data showing that 25 percent have a seasonal allergy – up significantly from two decades ago. Nearly seven percent have a food allergy, up about 50 percent from the 1990s.
And this doesn’t happen overnight. Before a rapidly swelling throat or potentially deadly anaphylactic shock, experts say there are warning signs of a developing allergy.
The body quietly builds up its defenses over time. You might eat shrimp or nuts and feel just a tiny itch on your tongue or throat – a mild sign that your immune system is starting to flag the food as a threat.
That low-grade reaction can persist for months or even years as your immune system gradually ramps up its production of allergy-related antibodies.
‘Once in a while, it can become dramatic, where your tongue swells, your mouth swells, and your lips swell, and you can’t even breathe,’ Dr Angie Sadeghi, an internal medicine physician, told the Daily Mail.
So what are the red flags, and how can you protect yourself?
The first step is recognizing that allergies are not just a childhood problem. They can strike anyone, at any age.
Before a full-blown allergic reaction turns into a medical emergency, your body sends clear warning signals
More adults are developing new food allergies later in life, according to a 2019 study. Among the more than 27 million US adults with food allergies, nearly half developed at least one food allergy after they turned 18, and 21 percent say that all of their food allergies began after age 18.
Meanwhile, an analysis of private insurance claims from 2007 to 2016 showed a staggering 377 percent increase in food allergy-related anaphylaxis treatment claims during that period, with more than a third involving adults 18 and older.
Researchers believe the cause to be a combination of environmental and lifestyle changes, not genetics.
The leading theory centers on the gut microbiome. Diets heavy in processed foods and low in fiber disrupt the balance of bacteria that train the immune system, impairing the gut barrier and making it easier for allergens to trigger a reaction.
The hygiene hypothesis fits here too. In cleaner environments, the immune system doesn’t learn to tolerate allergens.
Environmental pollutants are also under scrutiny. Industrialization has flooded the environment with chemicals that can disrupt the epithelial barrier and promote allergic inflammation.
For shellfish – the most common adult-onset allergy – cross-reactivity is a key factor: dust mite and cockroach allergens share proteins with shrimp.
Regardless of the trigger, the body’s warning signs are often the same and can appear long before a life-threatening emergency, like anaphylaxis, which can cause throat swelling, difficulty breathing, a sudden drop in blood pressure and loss of consciousness.
The 377 percent rise in private insurance claims for food allergy-related anaphylaxis from 2007 to 2016 strongly indicates that severe allergic reactions are becoming substantially more common
‘When you have a true food allergy, it’s usually manifested as wheezing or swelling of the mouth, the throat, the tongue and the nose,’ Sadeghi said.
The mouth is the first point of contact with the food. For some, this is linked to Oral Allergy Syndrome – a condition that affects roughly six percent of people where the immune system reacts to certain proteins in raw fruits, vegetables, or nuts that are similar to those found in pollens.
This type of reaction can arise at any age but is most commonly seen in adolescence and early adulthood. It is usually mild and short-lived, and many people can tolerate the same foods if they are cooked.
A true food allergy can also cause gastrointestinal symptoms. ‘When you have an allergic reaction, the gut is connected to everything,’ Sadeghi explains. ‘The gut is our second brain.’
Signals from an allergic reaction in the mouth and throat can travel through the nervous system to the gut, making you feel sick to your stomach, triggering nausea, cramping or even diarrhea.
These indicate that histamine – a chemical released by immune cells when the body mistakenly identifies a harmless food protein as a threat – is being released, which is the hallmark of a developing allergy.
Histamine triggers classic allergy symptoms like itching, hives, swelling and, in severe cases, throat tightening or difficulty breathing.
One in three US adults has a diagnosed allergy. Seasonal allergies top the list at 25 percent, followed by eczema at 8 percent and food allergies at nearly 7 percent
In some cases, particularly with adult-onset Food Protein-Induced Enterocolitis Syndrome (FPIES), a rare food allergy that doesn’t involve typical IgE antibodies, the reaction is delayed.
Instead of immediate hives or anaphylaxis, it causes severe vomiting, diarrhea and abdominal pain, driven by T-cells that release inflammatory signals and increase intestinal permeability. In adults, vomiting may be absent and severe pain is often the main symptom.
FPIES is more common in children, affecting about five in 1,000 kids compared to two in 1,000 adults.
However, it can develop in adulthood, with about 80 percent of adult cases occurring in women. Common triggers in kids are milk and grains; in adults, seafood is the top trigger.
Reports of adult FPIES are increasing. Better awareness plays a role, but researchers believe environmental and lifestyle changes are driving a genuine rise.
Seasonal allergies, too, are striking adults later in life with surprising frequency.
Rising temperatures are lengthening pollen seasons, increasing pollen production, and making allergens more potent.
Research published in The Lancet Planetary Health showed that pollen seasons across the Northern Hemisphere have extended by an average of 20 days and pollen concentrations have increased by 21 percent since 1990.
For adults who never had allergies before, this means suddenly finding themselves sneezing, congested, and reaching for antihistamines, sometimes decades after they thought they were in the clear.
Climate change is the biggest driver of adult-onset seasonal allergies. Rising temperatures are lengthening pollen seasons, increasing pollen production and making allergens more potent.
In Chicago, researchers found that sensitization to tree pollen jumped from 49 percent to nearly 70 percent, and grass pollen from 58 percent to 100 percent in just a few years.
Pollution, particularly ozone, diesel exhaust and fine particulate matter, acts as an ‘adjuvant,’ meaning it primes the immune system to overreact to any allergen it encounters.
These pollutants damage the epithelial barrier in the airways, skin and gut, making it easier for allergens to penetrate and trigger a response. This is not limited to pollen; it applies to food proteins, dust mites and pet dander as well.
Meanwhile, more time indoors means greater exposure to dust mites, pet dander and mold, all of which can push a person past their ‘allergy threshold.’
Sadeghi advised identifying your trigger and avoiding it at all costs. It might also require allergy shots, which work by gradually desensitizing the immune system to the allergen over time, reducing the severity of reactions.
There’s also hope beyond avoidance. Antihistamines, nasal sprays and allergy shots can help train your immune system to tolerate triggers over time.
The key is knowing your body, having a plan and never hesitating to act when a reaction starts.
