The research team, led by Chao Chen of the hospital’s Pediatric Intensive Care Unit and corresponding author Xuefeng Jin of the Department of Gastroenterology, retrospectively analyzed 115 pediatric patients treated for anaphylaxis between January 2021 and October 2024. The dataset covered age, gender, suspected triggers, allergy history, clinical manifestations, treatments administered, adverse reactions, and outcomes. To probe the safety profile of adrenaline itself, the researchers also collected adverse reaction data from 70 children who received intramuscular adrenaline for reasons unrelated to anaphylaxis. That second cohort matters, because a persistent barrier to prompt adrenaline use in emergency settings is fear of the drug’s side effects, particularly in small bodies. By examining children who received adrenaline outside the anaphylaxis context, the study could test whether that fear is grounded in reality.

What the team found about triggers will not surprise allergists, but the proportions are instructive. Food allergens were the leading suspected cause, implicated in 52 of the 115 cases, or 45.22 percent. Drug allergens came second at 34 cases, or 29.57 percent. Only 37 of the 115 children had a documented prior history of allergy, a striking statistic given that anaphylaxis is often assumed to strike children with known allergic profiles. In practice, a majority of the children in this cohort were experiencing a severe reaction without any prior warning on their medical record. That gap between expectation and reality is precisely what makes anaphylaxis so difficult to diagnose in pediatric emergency departments, where a first presentation may look like an ordinary allergic reaction until breathing difficulties escalate.

The clinical picture that emerged from the case records was dominated by two organ systems. Skin and mucosal involvement was the most common manifestation, present in 108 of 115 patients, or 93.91 percent, and it typically appeared as urticaria, the raised, itchy welts commonly called hives, or as angioedema, the deeper swelling of tissues beneath the skin. Respiratory symptoms were a close second, occurring in 104 patients, or 90.43 percent, with presentations that included cough, wheezing, dyspnea, and laryngeal edema, the swelling of the voice box that represents one of the most dangerous features of anaphylaxis in children. The near-universal overlap of skin and breathing symptoms underscores why pediatric guidelines emphasize that anaphylaxis is a clinical diagnosis: when hives appear alongside any respiratory compromise after a plausible exposure, the clock starts immediately.

Against that backdrop, the adrenaline data tell a nuanced story. Intramuscular adrenaline was administered to 101 of the 115 patients, or 87.83 percent, and 91 patients, or 79.13 percent, received it as first-line treatment. On one level, those numbers are encouraging, since they suggest that the majority of children in this Chinese tertiary pediatric hospital were treated in line with international guidelines that place adrenaline at the front of the protocol. On another level, the remaining gap is significant. Roughly one child in eight did not receive the drug at all, and about one in five did not receive it first, despite the drug being the single intervention most strongly associated with survival in anaphylaxis. Every minute of delay allows airway swelling and vascular collapse to progress, and delayed administration is one of the most consistently documented failures in anaphylaxis care worldwide.

The safety findings may prove to be the study’s most consequential contribution. Across both the anaphylaxis group and the 70 children who received intramuscular adrenaline for non-anaphylaxis indications, no adverse reaction was observed. Not one significant adverse event was reported in any of the children treated with adrenaline. For a drug whose perceived danger often delays its use, that result is a pointed rebuttal. Adrenaline, or epinephrine as it is known in much of the world, is a naturally occurring hormone and neurotransmitter, and when delivered intramuscularly at pediatric doses it produces a transient physiological response rather than the dangerous arrhythmias clinicians sometimes fear. The fear, the data suggest, is largely inherited from outdated practice patterns involving intravenous administration rather than from the intramuscular route recommended today.

The authors frame the problem as a dual challenge: delayed adrenaline administration on one side and excessive prophylactic use on the other. The second half of that equation deserves attention. In settings where adrenaline is given reflexively to children whose reactions do not meet the criteria for anaphylaxis, the drug loses its signal value and clinical teams risk normalizing unnecessary interventions. The Hangzhou dataset, which deliberately included non-anaphylaxis adrenaline recipients, was designed to illuminate exactly this tension. Balancing the two errors, under-treatment and over-treatment, requires better diagnostic precision at the bedside, not more caution in one direction or the other. The study’s conclusion points toward a pragmatic resolution: given how difficult anaphylaxis is to diagnose in children, early administration of adrenaline when the condition is strongly suspected on clinical grounds may help optimize management overall.

Why does diagnosis remain so hard in children? Part of the answer lies in the presentation data itself. Urticaria and angioedema are extremely common in pediatric allergic reactions that never progress to anaphylaxis, so their presence alone does not settle the question. Respiratory symptoms such as cough and wheezing overlap heavily with viral infections, asthma exacerbations, and even foreign-body aspiration, all far more frequent than anaphylaxis in a busy pediatric emergency department. A clinician weighing whether a wheezing child with hives is experiencing anaphylaxis must integrate exposure history, reaction tempo, and evolving symptoms in minutes. The fact that only about a third of the children in this cohort had a known allergy history compounds the difficulty, because a blank allergy history can falsely reassure. Diagnostic uncertainty, not ignorance of the guidelines, is the engine of both delayed and excessive adrenaline use.

The study’s retrospective, single-center design means the numbers describe one hospital’s experience over nearly four years rather than a national picture, and cross-sectional analyses cannot establish causation or capture long-term outcomes. Still, the granularity of the dataset, spanning triggers, manifestations, treatment sequencing, and a dedicated safety cohort, makes it a useful mirror for pediatric departments anywhere. The core takeaways travel well: food and drugs cause the overwhelming majority of pediatric anaphylaxis, skin and respiratory signs dominate the presentation, most children arrive without a prior allergy diagnosis, and intramuscular adrenaline, given promptly, appears remarkably safe even beyond its intended indication. For parents, the practical lesson is that a child with hives plus any breathing difficulty after a food or medication warrants immediate emergency assessment, not watchful waiting. For clinicians, the message is subtler but equally clear: the evidence continues to favor giving adrenaline early when anaphylaxis is strongly suspected, because in this dataset the drug’s risks never materialized while the costs of hesitation remain written into the treatment delays the authors documented.

Subject of Research: Adrenaline use and clinical characteristics of anaphylaxis in children

Article Title: Clinical characteristics and adrenaline use in anaphylaxis in children: a cross-sectional study

Article References: Chen, C., Jin, X., Cai, J., Wang, J., Zhang, C., & Tang, W. (2026). Clinical characteristics and adrenaline use in anaphylaxis in children: a cross-sectional study. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07643-3

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07643-3

Keywords: anaphylaxis, children, adrenaline, epinephrine, food allergens, drug allergens, pediatric emergency care, urticaria, angioedema, cross-sectional study, BMC Pediatrics, allergy

The study, led by Mingqian Zhang, Ziyi Li, Lei Liu and Hai-Chen Wu of the Institute of Chemistry at the Chinese Academy of Sciences together with colleagues, reconstitutes the complete catecholamine biosynthetic pathway in a test tube using purified enzymes and their required cofactors. The researchers then coupled this miniature chemical factory to an engineered protein nanopore — a nanoscale pore embedded in a membrane through which an ionic current flows. Whenever a metabolite from the pathway interacts with the pore, it briefly perturbs that current, producing an electrical fingerprint specific to that molecule. By reading these fingerprints as they accumulate, the team could follow the transformation of each intermediate into the next, second by second.

The technical heart of the work lies in how the researchers achieved specificity. Small molecules are notoriously difficult for nanopores to distinguish because they zip through the pore too quickly and too subtly to leave clean, separable signals. The team solved this by integrating two orthogonal molecular recognition modalities within a single nanopore platform. In essence, different chemical strategies were used to make different members of the pathway register at the pore: some metabolites, such as the catecholamines themselves, generate characteristic blockade patterns as they translocate, while the amino acids phenylalanine and tyrosine were detected through a tailored probe chemistry involving a copper-coordinated molecular adaptor and a cucurbituril host that captures the amino acid and presents it to the pore as a distinct complex.

With this dual recognition scheme in place, the researchers demonstrated highly specific detection of all six key players in the pathway: phenylalanine, tyrosine, levodopa, dopamine, noradrenaline and adrenaline. Extended data traces show characteristic current blockades and dwell-time distributions for each analyte at 100 micromolar concentration, recorded in a high-salt buffer at a transmembrane potential of +100 millivolts. Gaussian fits to the blockade histograms and single-exponential fits to the dwell times confirm that each metabolite produces a statistically distinct signature, which is the prerequisite for unambiguous identification in a mixed sample.

Having validated each molecule individually, the team turned to the full cascade. They initiated the enzymatic sequence and sampled the reaction mixture every five minutes, feeding each sample to the nanopore. The resulting single-channel recordings amount to a time-lapse film of neurotransmitter synthesis: phenylalanine signals fade as tyrosine rises, tyrosine gives way to levodopa, and levodopa is converted onward to dopamine, noradrenaline and finally adrenaline. Because the readout is label-free and single-molecule, nothing was added to the reaction to make it visible, and no amplification step could distort the quantitative picture of pathway dynamics.

This time-resolved view matters because the catecholamine pathway is not a simple conveyor belt. It is a branched network whose flux is governed by enzyme kinetics, cofactor availability and regulatory feedback, and disruption at any node is implicated in conditions ranging from Parkinson’s disease and attention-deficit hyperactivity disorder to orthostatic hypotension and stress-related endocrine disorders. Conventional analytical methods — liquid chromatography, mass spectrometry, electrochemistry, ELISAs — can measure metabolite concentrations at chosen endpoints, but they are generally snapshot techniques that require aliquots, labels or lengthy separation steps, making continuous, coupled monitoring of a multi-enzyme cascade cumbersome.

The platform also opened a window on pathology. A striking application involves iodotyrosine dehalogenase 1, or DEHAL1, an enzyme best known for recycling iodide in the thyroid, where it removes iodine from iodinated tyrosine residues. Defects in the DEHAL1 gene cause hypothyroidism, and 3-iodo-L-tyrosine, the substrate of this enzyme, has long been known to inhibit tyrosine hydroxylase, the rate-limiting enzyme that converts tyrosine to levodopa. The researchers used their nanopore assay to examine what happens to the catecholamine cascade when dehalogenase activity is compromised. They found that 6-methylisothiocyanate, a compound that disrupts the dehalogenase, perturbs catecholamine biosynthesis in a way that offers a mechanistic explanation for how DEHAL1 deficiency may compromise neurotransmitter production — potentially linking an inherited thyroid disorder to impaired catecholamine output.

Figure 5 of the study, titled ‘Effect of thyroiditis-like disorders on catecholamine metabolism,’ presents this perturbation experiment, with extended recordings showing how the cascade changes when monoiodotyrosine is present. The single-molecule records reveal shifts in the relative abundance of the pathway intermediates, illustrating the value of the method: rather than inferring a block from diminished end-product levels, researchers can see exactly where flux stalls and which intermediates accumulate. That level of mechanistic detail is precisely what drug developers and enzymologists need when trying to dissect regulatory nodes in metabolic networks.

Broader implications extend well beyond catecholamines. The authors describe their integrated enzymology-and-nanopore-sensing platform as a general framework for studying complex biochemical pathways with single-molecule resolution. Because protein nanopores can be engineered with different recognition elements, the same design philosophy could in principle be applied to other branched metabolic cascades, to drug-metabolism studies, or to screening enzyme inhibitors in real time. The approach builds on two decades of stochastic sensing, in which engineered pores have been taught to identify analytes as diverse as metal ions, nucleotides, amino acids, peptides, proteins and microRNAs, and it extends that lineage from static identification to dynamic pathway monitoring.

The team has deposited its source data publicly on Zenodo, and the paper — received in December 2025, accepted in August 2026 and published on 1 September 2026 — carries no reported competing interests. What the work ultimately delivers is a new kind of laboratory instrument: a single pore through which the chemistry of a neurotransmitter can be watched being born. If the framework generalizes as its authors hope, metabolic biochemists may soon spend far less time taking snapshots of pathways and far more time watching them move.

Subject of Research: Time-resolved single-molecule monitoring of catecholamine biosynthesis from phenylalanine using an engineered nanopore sensor

Article Title: Nanopore-enabled time-resolved monitoring of catecholamine-related phenylalanine metabolism

Article References: Zhang, M., Li, Z., Hao, W., Yi, Y., Zhou, K., Liu, L., & Wu, H.-C. (2026). Nanopore-enabled time-resolved monitoring of catecholamine-related phenylalanine metabolism. Nature Nanotechnology. https://doi.org/10.1038/s41565-026-02273-3

Image Credits: AI Generated

DOI: 10.1038/s41565-026-02273-3

Keywords: nanopore sensing, catecholamines, dopamine, adrenaline, phenylalanine metabolism, single-molecule detection, neurotransmitter biosynthesis, DEHAL1, iodotyrosine dehalogenase, label-free biosensing, Nature Nanotechnology, enzymology