Case details have been composited and adjusted for teaching clarity and patient privacy.
A mother brought her daughter in for a second opinion. The child was not yet three years old, and she had already been through a full course of conventional allergy care: skin prick testing, an MRT leukocyte sensitivity panel, months of low-dose allergen (LDA) therapy, and a strict elimination diet that had helped, but not enough and had become extremely limiting for the family. The family was not looking to abandon the allergist’s plan. They wanted to know whether anything upstream had been missed before committing to years of immunotherapy, and whether the eczema, the food reactions, and her stalled growth were connected to something nobody had tested for yet, with a goal of being able to expand her diet, improve her health and support her immune system.
That question, what is underneath this, is the one functional medicine is trained to ask. Here is how the workup unfolded, and why the sequence of what we did mattered almost as much as what we did.
The history that mattered
The child’s eczema began at three months old, immediately following a strep skin infection that was treated with antibiotics in both mother and infant during breastfeeding. Food allergies emerged around her first birthday, including a frightening anaphylactic reaction to nuts. By the time she reached our clinic, she carried known allergies to dairy, eggs, and nuts, with milder sensitivities to soy, several nightshades, and gluten. She was also tracking below the growth curve for height, which her pediatrician was investigating separately for endocrine causes.
This timeline, early antibiotic exposure immediately preceding an eczema flare and then a cascade of food reactivity, is a pattern functional medicine clinicians are trained to pay attention to. Antibiotics in early infancy can disrupt the developing gut microbiome at exactly the point when it is teaching the immune system what to tolerate and what to attack. That disruption does not cause allergies on its own, but it is a plausible contributing thread, and it shaped how we built the workup: not just what is she reacting to, but why is her immune system reacting this way in the first place.
Building the immune and gut picture
We started broader than a standard allergy recheck. Alongside a comprehensive metabolic panel and CBC, we ordered quantitative immunoglobulins, IgE, plasma histamine, tryptase, ANA, strep antibodies, and an ASCA IgG, a marker sometimes associated with inflammatory bowel disease, included here to cast a wide net on gut-immune inflammation. The good news is that the majority of her nutrient levels were optimal other than Vitamin D, which was low at 24. Her parents had done a great job of keeping her supplemented and supported while her diet had been so limited.
A few findings started to shape the initial treatment plan and next steps. IgA came back low. In an adult that is often worth chasing further, but a reminder that transient low IgA is common in toddlers and frequently self-resolves by age four to six as the immune system matures, so we flagged it to the family as something to watch rather than something to treat. This is important practice: functional medicine still needs to know when a marker is a genuine red flag versus expected biological noise for the patient’s age, and treating every low value as pathology can be the wrong direction. Identifying patterns, matching them to history and presentation, then prioritizing steps is the best path forward.
IgE was markedly elevated at intake and climbed further over the following year, roughly doubling. Plasma histamine was also elevated initially, while tryptase stayed within normal limits. That specific combination, high histamine and IgE without elevated tryptase, pointed toward a mast cell activation pattern rather than a primary mast cell disorder such as systemic mastocytosis, where tryptase would typically be elevated as well. This was helpful information because it starts to paint a picture of how best to approach this case. It meant we could focus on stabilizing mast cell reactivity rather than pursuing a hematology workup, though we kept KIT D816V mutation testing in reserve in case the picture changed.
| Marker | Normal Range | Before | After |
|---|---|---|---|
| Histamine, Plasma | 0-8 nmol/L | 43 nmol/L | 17 nmol/L |
| IgE Quantitative Serum | <60 IU/mL | 1,122 IU/mL | 2,158 IU/mL |
Clinical Pearl: A practical note for clinicians newer to this testing: histamine and tryptase are both finicky, and interpreting them well means understanding their limits. Plasma histamine is metabolized within minutes, so a level drawn outside an active reactive window can look deceptively normal in a patient with clear mast cell symptoms, and improper specimen handling, a delayed spin or hemolyzed sample, can just as easily inflate it artificially. Serum tryptase is more stable and reflects overall mast cell burden rather than acute activation, which is exactly why it is useful for ruling out mastocytosis, but a single normal tryptase does not rule out episodic MCAS, since tryptase often stays flat even during a genuine reaction. In practice, this means one draw rarely tells the full story. Trending these markers over time, and timing collection near a symptomatic episode when feasible, gives far more useful information than a single snapshot.
IgG subclasses 3 and 4 were also elevated, a marker not commonly checked outside functional medicine and immunology circles. On its own it is not diagnostic of anything specific, but it added texture to the picture, consistent with a chronically activated humoral immune response, and it reinforced rather than redirected the rest of the story.
What the stool testing added
We ran a GI-MAP stool panel early and repeated it over the course of care to track change. The first round showed a dysbiotic pattern with several opportunistic organisms overgrown, low Akkermansia muciniphila, a keystone species associated with a healthy mucosal lining, and on a later round, elevated calprotectin and zonulin, markers of intestinal inflammation and increased gut permeability, respectively.
This combination of low protective flora alongside signs of a compromised gut barrier, is a common substrate underneath allergic and eczematous presentations. If the gut lining is more permeable than it should be, larger food protein fragments can cross into circulation and provoke immune reactivity that would not otherwise occur across an intact barrier. This is the piece a standard allergy workup does not typically investigate, and it became the anchor for the treatment sequence that followed.
Why toxin testing came next
With the allergy and gut findings mapped, we extended the workup into environmental exposures, an area conventional allergy care does not routinely screen for but that functional medicine treats as standard inquiry once the immune system already looks dysregulated. When diving into the family’s history, it was discovered that they live next to a golf course and have had a history of water leaks in their previous home where she spent the first year of her life. Mold and mycotoxin showed moderate burden of mycotoxins and immune reactivity. A separate environmental toxins panel showed elevated glyphosate and 2,4-D, both common herbicide residues.
Home ERMI dust testing, a mold-specific index for indoor environments, came back in the statistically safe range. That negative result was as useful as a positive one. It suggested the mycotoxin exposure was not necessarily coming from the current home, and it kept the family from pursuing expensive remediation that likely would not have moved the needle.
Sequencing the treatment, not just choosing it
Phase one focused on symptom stabilization and gut foundation rather than aggressive treatment. I often use this metaphor with patients here: “You can’t rearrange the furniture while the house is on fire.” Before we can dig for root cause drivers, we first have to address the burdens that are actively driving reactivity, immune load, and quality of life.
The initial plan combined pediatric dosing for cromolyn sodium, a mast cell stabilizer titrated up gradually, cetirizine, DAO enzyme support, a pediatric quercetin and antihistamine blend, vitamin D and K2, micellized vitamin A, omega-3s, a butyrate supplement, and a Lactobacillus rhamnosus GG probiotic. Nothing here targeted a pathogen or pushed aggressive detoxification. The goal was to calm mast cell reactivity, likely driving much of the itching, while feeding and supporting the gut lining with butyrate, a short-chain fatty acid that is a primary fuel source for colon cells, alongside a well-studied probiotic strain.
Antimicrobial and binder support did not start until the gut foundation was in place, roughly two months later. Once butyrate and probiotics had been on board for a few months, we added safe and gentle herbal antimicrobials, specifically liquid Biocidin, Andrographis and a prebiotic fiber blend and aloe vera juice. The fiber and aloe served a specific purpose here: when you disrupt dysbiotic organisms, you want a way to bind and help eliminate what is released, rather than clearing pathogens and hoping the gut handles the fallout on its own. This support-first-then-clear sequencing is a recurring functional medicine principle, and it explains why the antimicrobial phase did not begin on day one even though the stool testing showed dysbiosis early.
Antifungal support was layered in as the antimicrobial gut treatment was being added. Monolaurin, derived from lauric acid and carrying antifungal and antimicrobial properties, and holy basil tea were layered on top of the existing foundation rather than started alongside everything else.
Diet reintroduction started next. Again, we are working to stabilize immune reactivity and optimize the gut before we start adding foods back slowly, under a nutritionist’s guidance. Rather than a blanket reintroduction, we added foods back one at a time, starting with lower-allergenicity options like canned salmon, tofu, and alternative grains such as sorghum, teff, and amaranth, while monitoring calcium and iodine intake given the dairy restriction. We are working to expand the diet only as fast as the gut and immune system demonstrate they can tolerate it, using symptoms as the feedback loop rather than a fixed calendar.
Throughout, we addressed the environmental toxin findings practically rather than dramatically, walking the family through where glyphosate and 2,4-D exposure most often comes from, conventional produce and lawn treatments among them, and giving realistic reduction strategies rather than a costly, aggressive detox protocol for a toddler. This might look like researching what the local golf course is using for sprays, when the spray, the movement of air in from golf course to their house to understand and mitigate pesticide drift, keeping windows closed during that time, high quality air filters, water filters, etc.
Where we are now
By the most recent visit (6 months into treatment), the diet had expanded meaningfully. A child previously restricted to lamb, elk, rabbit, turkey, bison, quinoa, and millet was tolerating banana, avocado, several fish, beef, and chicken. The family described her eczema as under control, with flares now tied mainly to illness rather than food exposure. Plasma histamine dropped substantially over the course of care, though it remained slightly above the reference range. Immunoglobulin subclasses improved on repeat testing as well. Itching and difficult sleeping had resolved and parents reported a less “bothered” child. Vitamin D levels have improved to 41 ng/ml. Repeat serum IgA levels also normalized with repeat testing.
Here is another important part and why I am including this information because the reality is that not everything tracks perfectly or makes sense! Even in the context of all these improvements, her serum IgE, roughly doubled over the same period, despite the clinical picture improving. This didn’t match what I was seeing in practice or with the other labs and we flagged it as such rather than explaining it away. It is a reminder that in a complex, still-developing immune system, biomarkers and symptoms do not always move in lockstep, and a good clinician tracks both rather than declaring victory off of one.
No eggs or nuts have been reintroduced. The family now coordinates care between our practice and an outside allergist, who is planning oral immunotherapy for dairy, egg, and gluten. Cromolyn and possibly omalizumab are being discussed as adjuncts to make that immunotherapy safer and better tolerated. This is a good example of what integrated care can look like in practice. Functional medicine did not replace the allergist’s plan. It built a foundation that may make the conventional treatment work better.
What this case illustrates
None of the individual pieces here are exotic. Stool testing, IgE and histamine panels, environmental toxin testing, and organic acids testing are all things a curious clinician could learn to order and interpret. What functional medicine training actually teaches is the sequencing logic: why you stabilize before you clear, why you screen gut permeability before assuming a single food is the villain, why a positive mycotoxin panel does not automatically mean aggressive detox, and how to hold a marker like rising IgE as data to keep watching rather than a verdict on whether the plan is working.
That is the kind of clinical reasoning this case was built to demonstrate. It is also the kind of reasoning we walk through in more depth, case by case, inside the ADAPT Practitioner Training Program, for clinicians who want to build this way of thinking into their own practice.
