Adult Allergies and Atopic Disease Aren’t Random

They’re a signal your immune system has lost tolerance — and it can be rebuilt

If your allergies started in adulthood, or your “mild seasonal” symptoms have turned into daily congestion, eczema, asthma-like tightness, food reactions, or hives… you’re not imagining it.

Most adult atopic disease is not a genetics story. It’s a modern-environment story:

• We live indoors more than ever.

• We breathe more irritants (VOCs, fragrances, building materials, combustion byproducts).

• We absorb more chemicals (personal care, cleaners, plastics).

• We eat more ultra-processed products that stress the gut barrier and microbiome.

We run our nervous systems hot for years, then wonder why the immune system becomes hyper-reactive.

Your immune system is doing exactly what it was designed to do: respond to danger signals. The problem is that modern life creates a steady stream of those signals.

This article will help you understand the “why” and what to do next — especially if you’re dealing with unexplained hives or autoimmune urticaria.

The biodiversity hypothesis: your immune system needs training data

One of the most important ideas in modern immunology is the biodiversity hypothesis.

Humans evolved in constant contact with soil organisms, plants, animals, and a rich outdoor microbial world. Those exposures weren’t “gross.” They were information. They helped train immune tolerance — teaching your immune system what to ignore and what to fight.

Modern living strips that away. Less outdoor contact. Less microbial diversity. More sterile indoor environments. More chemicals. More antibiotic exposure. Less resilient microbiomes.

When that immune “education” is missing, the system becomes more likely to misfire — and allergy and atopic disease are common outcomes.

This matters because it shifts the goal from “avoid everything forever” to: restore tolerance by changing the inputs.

The core mechanism behind adult-onset allergies: barrier breakdown

Allergic disease is often described like the immune system “overreacts.” That’s not wrong, but it’s incomplete.

A more useful clinical view is this: your barriers are supposed to control exposure.

Your gut lining, airway lining, and skin are all part of the same defensive architecture. When those barriers are inflamed or compromised, your immune system gets exposed to more particles, more proteins, more irritants, more often — and it begins reacting to things it used to tolerate.

So when someone says, “I never had allergies before,” I don’t hear “bad luck.” I hear: something changed in the terrain.

Common barrier disruptors include:

• chronic stress and poor sleep

• processed foods and high sugar intake

• alcohol

• NSAID overuse

• frequent antibiotics

• acid suppression medications (in the right context, these can change digestion and antigen exposure)

• chronic sinus inflammation / post-nasal drip patterns

• skin inflammation that becomes a chronic loop

• moldy or damp building exposure

• high chemical/fragrance exposure

This is why adult allergy often travels with other symptoms: fatigue, brain fog, GI problems, headaches, insomnia, anxiety, “wired but tired.” It’s not separate problems — it’s one body trying to defend itself.

Adult allergies can be driven by toxicity and exposure load

Some people are uncomfortable with the word “toxicity.” I’m not.

Your immune system is exquisitely responsive to environmental exposures. And in my world, it’s common to see allergic symptoms worsen alongside higher exposure load — especially with:

• fragrances and air fresheners

• VOCs from paint, new flooring, furniture, car interiors

• pesticides and herbicides

• plastics (especially heat + plastics)

• personal care products with endocrine-disrupting chemicals

• poor indoor air quality

• water issues (chlorination byproducts for some people)

• damp or moldy environments (biologic VOCs matter)

The clinical point is simple: if the immune system is already reactive, stacking exposures makes reactions louder. Reducing exposures doesn’t “fix everything,” but it can lower the baseline enough for true healing to take hold.

Chronic hives: the adult symptom that deserves a real explanation

If you’ve had hives that seem random, daily, or recurrent — or hives plus swelling — you’ve likely been told some version of: Idiopathic. Unknown. No cure. Take antihistamines. Good luck.

That is not acceptable.

Hives are usually a mast-cell driven phenomenon. Mast cells sit at barrier surfaces (skin, gut, airways). When they perceive threat signals, they release mediators. Histamine is one mediator. It is not the only one.

This is why someone can be “on antihistamines” and still feel awful. If the immune system is releasing multiple mediators and the upstream drivers are still present, you’re managing one branch while the root keeps feeding the tree.

Autoimmune urticaria: when the immune system is triggering mast cells from the inside

Some chronic spontaneous urticaria has an autoimmune mechanism — meaning the immune system is stimulating mast cells even without a clear external allergen.

This often overlaps with other autoimmune patterns (thyroid autoimmunity is a common one to rule out). It may present as:

• daily or near-daily hives

• hives that persist for months

• hives plus swelling (angioedema)

• flares without a consistent food trigger

• symptom clustering (headaches, fatigue, brain fog, GI disruption)

Autoimmune urticaria is one reason “just avoid gluten” or “it’s probably detergent” is not a plan.

A plan is: stabilize, investigate, reduce triggers, rebuild barriers, restore microbial balance, lower exposures, and address immune dysregulation.

The lab details that matter: histamine and tryptase timing

If mast-cell activation is suspected, people often get labs that come back “normal” — and then they’re told nothing is happening.

Timing matters.

Histamine has a short half-life, so a random blood draw on a “good” day is unlikely to capture what’s happening during a flare. When histamine is evaluated, it’s most meaningful when drawn during active symptoms, and interpreted alongside the clinical picture.

Tryptase is most useful when measured during an acute flare — ideally within 2 hours of symptom onset. A baseline (symptom-free) level can be compared to a flare level to look for meaningful change.

This is one of many reasons people fall through the cracks: the right test done at the wrong time becomes a misleading test.

What actually helps: a professional, adult framework that rebuilds tolerance

When someone comes to us with adult atopic disease — especially unexplained hives — the goal is not to chase symptoms forever.

It’s to rebuild the conditions that create immune tolerance.

Here’s the high-level sequence we use clinically:

1) Stabilize the system so you can function

This may include targeted symptom support while we work on deeper drivers. If you can’t sleep, if you’re swollen, if your skin is on fire, if you’re anxious because your body feels unsafe — you need stabilization first. That’s intelligent sequencing.

2) Reduce exposure load (without making life miserable)

This is where real-world changes matter:

• remove fragrance from laundry and home

• clean up indoor air (filters, humidity control, ventilation)

• address dampness and mold properly

• remove obvious irritant products from skin care and cleaning

• stop heating food in plastic

• simplify food ingredients (whole foods > packages)

These are not “wellness hacks.” They are immune-lowering fundamentals.

3) Repair barriers

We look at the gut barrier, the airway/sinus barrier, and the skin barrier — because if exposure control is broken, the immune system stays on high alert.

4) Rebuild microbiome resilience

This is not “take random probiotics forever.”

This is targeted restoration, sometimes after removing ongoing disruptors. The microbiome is part of immune education — and in modern adults, it’s often a missing piece.

5) Identify immune dysregulation patterns

This includes assessing for autoimmune patterns when the symptom pattern fits, and ruling out overlooked drivers that keep the immune system activated.

Client story: Ashley L., RN

When I first started working with Dr. Thompson I was waking up with horrible hives everyday - - all over my body. Anytime something would irritate my skin (even something as simple as carrying in grocery bags) my body would breakout in itchy, painful hives. I was also having bad swelling and changes like bruises in my feet and ankles especially when I was running or working out.

None of my doctors could or would do anything about it, they called it “Idiopathic Urticaria,” and there is “NO CURE.” I had only developed this problem in the last year or so and it was ruining my daily life. It felt like just something I would have to live with forever, and it was making me really miserable. Additionally, I was actually developing angioedema which is a condition where your lips and tongue swell and can be life threatening. While my skin was the worst part I was also having daily migraine headaches multiple times a week, I was exhausted because I couldn’t sleep with the itching and I felt like my brain just didn’t work. My stomach was a mess and I was craving foods all the time, but then didn’t feel like I could eat. I was new to my career and I had horrible brain fog, and I couldn’t make simple decisions. I was having to call out of work because I looked and felt so terrible.

I had seen two specialists and my primary, was taking 5 different medications and 2 supplements and I was only getting worse.

Dr. Thompson spent a lot of time going through my history and we did a special GI MAP test and some blood work to pinpoint the root cause of the problem. We then made some diet accommodations and added in supplements to help heal my body. I was making progress very quickly and I stuck with the program. I learned that I have a lot of willpower and if I truly set my mind to it I can make any changes I want to.

I was most surprised about how easy it was to reach out to Dr. Thompson. She was always available to answer any questions or ease any concerns especially when I had what felt like an enormous set back. But she had a plan and we moved past the hardest parts of the treatment phase.

After only 8 weeks, I have not had any headaches except for very mild, common headaches. NO migraines! No G.I. upset bloating and belching or cravings, mood has been excellent, no fatigue brain fog or decision making difficulty. MY MSQ score went from 86→ 32 in just 8 weeks and I know it is continuing to improve. My days are hive free and am generally much more comfortable in my skin. I sleep well, am able to enjoy my life and travel, do my workouts and do my work!

What I want you to take from Ashley’s story

1. Idiopathic is not a diagnosis. It means the system stopped looking.

2. Chronic hives are often part of a broader immune dysregulation pattern — not just “skin.”

3. When you investigate the drivers and sequence the work, the body often responds faster than people think is possible.

4. You deserve a clinician who takes this seriously and stays with you through the process.

If you want to learn more

If you want to learn more, visit my website https://grow.rootcausedoc.com/root-cause-mini-masterclass and watch my new training.