The silent chest phenomenon is the most dangerous clinical finding in acute paediatric asthma — the absence of wheeze in a severely distressed child signals near-complete airway obstruction, not resolution. Wheeze requires turbulent airflow through narrowed bronchi; when obstruction is critical, there is insufficient flow to generate sound. Clinical correlates that accompany a silent chest: markedly increased work of breathing (subcostal, intercostal, and suprasternal recession), tachycardia, pallor or cyanosis, and deteriorating consciousness. Any child who was wheezing and then becomes quiet while still distressed is getting worse. BTS/SIGN 158 severity thresholds to memorise: Moderate = SpO₂ ≥92%, PEF ≥50%, able to talk. Severe = SpO₂ <92%, PEF 33–50%, too breathless to talk/feed, HR >140 or RR >40 (age 2–5); HR >125 or RR >30 (over 5) — any one feature. Life-threatening = SpO₂ <92% + any of: silent chest, cyanosis, poor respiratory effort, exhaustion, altered consciousness. The foreign body inhalation differential is particularly important in pre-school children, in whom most inhaled foreign bodies occur. Common objects: coins, small toy parts, nuts, grapes, hard sweets. The clinical pattern: sudden onset of coughing/choking (the inhalation event), followed by asymmetric wheeze (object lodges in a mainstem bronchus — usually the right, which is wider and more vertically oriented). Failure of salbutamol to improve wheeze in a toddler = foreign body until excluded by chest X-ray and bronchoscopy. Note that a normal chest X-ray does not exclude a foreign body (most FBs are radiolucent).

The viral-induced wheeze vs atopic asthma distinction in pre-school children has critical management implications — VIW is driven by non-specific bronchospasm during viral URTIs without underlying eosinophilic inflammation, whereas early atopic asthma has persistent airway eosinophilia that ICS targets. Multiple RCTs show ICS does NOT reduce VIW episode frequency or severity — meaning a child with pure VIW prescribed daily ICS receives steroid exposure without benefit. The clinical discriminators: VIW has wheeze exclusively with viral URTIs (no exercise, cold air, or allergen-triggered episodes), complete absence of any symptoms between viral illnesses, no personal or family atopic history. Early atopic asthma has multiple trigger types, interval symptoms (wheeze on non-viral days), and atopy. When uncertain in an under-5 whose symptoms need maintenance treatment, an 8–12 week trial of twice-daily paediatric low-dose ICS is the NG245 approach ("Consider stopping ICS and SABA treatment after 8 to 12 weeks if symptoms have resolved. Review symptoms after a further 3 months.") — response to ICS in terms of episode reduction supports atopic asthma and justifies continuation. For VIW, intermittent SABA PRN (and possibly intermittent ICS at the start of each viral episode — evidence for this is emerging) is the preferred approach. Vocal cord dysfunction in adolescents mimics exercise-induced asthma so closely that some teenagers diagnosed with exercise-induced asthma actually have VCD. The key diagnostic question: does the wheeze/stridor occur on inspiration (suggests VCD — vocal cord adduction restricts inspiration) or on expiration (suggests asthma — expiratory airflow limitation in obstructed bronchi)? Most teenagers cannot answer this accurately, making exercise spirometry with flow-volume loop analysis (showing inspiratory flattening) and laryngoscopy (visualising the paradoxical vocal cord movement) the gold standard investigations.

NICE NG245 (Asthma: diagnosis, monitoring and chronic asthma management, November 2024, joint with BTS and SIGN; it replaced NG80) requires objective testing to confirm asthma in children aged 5 and over, rather than allowing symptom-based diagnosis alone. The FeNO test is placed first in the diagnostic pathway because it is non-invasive, quick, not affected by recent bronchodilator use, and directly measures the eosinophilic inflammation that ICS targets. A FeNO of 35 ppb or more in a child aged 5–16 with typical asthma symptoms is a positive test under NG245 and points to ICS-responsive eosinophilic inflammation; interpret it together with the rest of the NG245 algorithm. A lower FeNO does not rule asthma out: NG245 continues to bronchodilator reversibility and then PEF variability, and a persistently low FeNO with poor control prompts thought about other diagnoses (VIW, exercise-induced bronchoconstriction without eosinophilia, VCD). The practical implication: FeNO can prevent both under-treatment (missing asthma diagnosis) and over-treatment (prescribing ICS to a non-atopic child with VIW). GPs who do not have FeNO can use spirometry + PEF diary as the objective confirmation. The key quality standard is: do not diagnose asthma and start ICS based on symptoms alone without at least one objective test result. QOF has also rewarded recording objective tests at the time of an asthma diagnosis (check the current year's indicator wording).

The 15-minute reassessment after initial salbutamol is the most practically important decision point in acute asthma management in primary care — if a child has received an age-appropriate dose of salbutamol via a correctly used spacer (critical — ensure the spacer is age-appropriate and held correctly) and shows no improvement in PEF, work of breathing, or SpO₂ at 15 minutes, this constitutes a poor response requiring 999 emergency transfer regardless of the absolute severity. The failure to respond to bronchodilator is more prognostically important than the initial severity classification. BTS/SIGN 158 applies at all ages, including 5 years and under: 2–10 puffs by pMDI and spacer (one at a time, 5–6 breaths per puff), titrated to response and repeated every 20–30 minutes as needed; 10 puffs if severe, adding ipratropium if the response is poor. Use pMDI + spacer where the child can use it; nebulise for severe distress, inability to cooperate or when clinically required — not simply because the child is young. High-dose salbutamol can cause tachycardia, tremor, hypokalaemia, arrhythmia and lactic acidosis; worsening tachypnoea is not always worsening bronchospasm. Reassess work of breathing, air entry, mental state and fatigue repeatedly. Adding ipratropium when the response to salbutamol is poor is evidence-based — a Cochrane review (Griffiths and Ducharme, 2013) found that adding an inhaled anticholinergic to a β₂ agonist in children with acute asthma reduced hospital admission by roughly a quarter. Atrovent 20 mcg MDI is the appropriate preparation (not the Atrovent UDV nebules, which require a nebuliser). GP emergency bags should contain salbutamol MDI + spacer + Atrovent MDI.

The near-fatal asthma history flag is a critical patient safety marker — a child who has ever been intubated and ventilated for asthma, admitted to PICU, or required IV bronchodilators carries an ongoing elevated risk of another near-fatal episode independent of current control status. These children must have: a clinical alert flag on their GP records, a personal asthma action plan with specific triggers and escalation steps, PICU-level emergency instructions, a low threshold for same-day hospital referral for any acute episode, and specialist respiratory follow-up at least 3-monthly. NICE NG245 and BTS/SIGN guidelines both identify previous near-fatal asthma as a top-tier risk factor for asthma death. GPs who receive discharge letters from PICU for asthma admissions should proactively create or update the clinical alert on the patient's record before the next routine encounter. The post-acute review within 2 working days reflects NICE QS25 (asthma quality standard: GP follow-up within 2 working days of emergency treatment for an asthma attack) — it provides the opportunity to: (1) confirm full recovery; (2) assess inhaler technique (a high-impact intervention — incorrect technique is common); (3) update the written personalised action plan so it matches the prescribed reliever regimen; (4) consider step-up if this was the 3rd+ oral steroid course in 12 months; (5) identify and address the trigger; and (6) ensure the child has a spare salbutamol at school. This review can be a telephone consultation for mild episodes but should be face-to-face for moderate episodes.

The prednisolone dosing principle in acute childhood asthma is consistently underpractised — BTS/SIGN 158 gives 20 mg once daily for ages 2–5 and 30–40 mg for over-5s (BNFC: 1–2 mg/kg, maximum 40 mg), usually for up to 3 days. A 3-year-old should receive 20 mg; not 5 mg, not 10 mg. Studies consistently show GPs systematically underdose prednisolone in acute paediatric asthma, resulting in slower recovery and higher relapse rates. The short course (usually up to 3 days, longer if needed for recovery) does not require tapering — adrenal suppression does not occur with courses under 7 days, and abrupt cessation is appropriate. Oral dexamethasone is used by some units as an alternative to prednisolone for acute asthma in children — trials and meta-analyses suggest a short course is of similar efficacy, with less vomiting — but it is not the BTS/SIGN 158 recommendation, so follow the local paediatric protocol. Some NHS trusts have adopted dexamethasone as their standard acute asthma steroid for children — GPs should be aware of this alternative. Ipratropium bromide (20 micrograms/puff by pMDI and spacer) is added for severe or poorly responsive episodes (BTS/SIGN 158). It works additively with salbutamol (different receptor — M3 muscarinic vs beta-2 adrenergic) and reduces hospital admission when given early in severe attacks. Keep it in the emergency bag for the severe or poorly responding child.

Montelukast neuropsychiatric effects — highlighted in MHRA Drug Safety Updates (September 2019, and April 2024, when a boxed warning was added to the product information) — are important to discuss at every montelukast prescription: the drug can cause sleep disturbances (nightmares, insomnia), behavioural changes (aggression, irritability, anxiety), and in some children, depressed mood. These effects are reversible on stopping. The GP should: (1) inform the parent/carer at prescription; (2) review at 2–4 weeks specifically asking about sleep and behaviour; (3) document the discussion. The benefit-risk balance for most children remains favourable — montelukast is an excellent drug for atopic asthma, VIW, exercise-induced asthma, and combined asthma-rhinitis. But awareness of neuropsychiatric effects means problems are identified early. The LABA safety issue in children — LABA monotherapy without concurrent ICS is absolutely contraindicated in asthma (increases asthma death risk). LABAs should only be prescribed in children in a combined ICS/LABA formulation (Seretide, Fostair, Symbicort) — never as separate prescriptions. NICE NG245 and BTS/SIGN both emphasise this. GPs reviewing asthmatic children's repeat prescriptions should check that any LABA is co-prescribed with an ICS in the same device.

The school asthma action plan is a separate document from the home WAAP — schools require a specific form that names the child, their prescribed inhalers and reliever regimen, the agreed action-plan steps (symptom-based, with PEF thresholds only where individually agreed), and emergency contact details. The Asthma + Lung UK and NHS provide free downloadable templates. Research shows that children with a documented school asthma management plan have significantly fewer school-day absences from asthma and fewer acute attacks during school hours than those without one. Where PEF is included in a selected child's plan, the personal best PEF requires a stable period of good asthma control to establish — it should be the highest PEF recorded over 2 weeks of twice-daily measurements when the child is well. This personal best is more useful than predicted PEF (which is based on height and may overestimate what the child achieves) because it reflects the child's individual maximum airway calibre. Update the personal best PEF at every annual review if the child has grown, as the airways grow with them. The annual height measurement on an ICS is a medicolegal requirement — GPs must document annual height measured on a stadiometer (not estimated), plotted on a centile chart, and compared to the previous year's measurement. Declining height velocity (>1 centile channel crossed) should prompt review of whether ICS dose can be reduced.

The step-down principle is as clinically important as step-up in paediatric asthma management — many children remain on ICS doses that are higher than necessary because GPs are cautious about reducing them. BTS/SIGN 158 (2019) advised that once asthma has been well controlled for 3 months, a 25–50% reduction in ICS dose should be attempted, with reassessment after 3 months; NG245 likewise advises considering stepping maintenance therapy down once asthma is controlled. The purpose is twofold: (1) minimise systemic exposure to corticosteroids (growth effects, adrenal suppression at high doses); (2) establish the minimum effective dose for that patient. In practice, many children in the UK are maintained on medium-dose ICS indefinitely without regular step-down attempts. An annual review that includes considering whether step-down is appropriate (using the question 'has this child been well-controlled for the past 3 months?') is good practice. Children who have had no exacerbations and no SABA use in the past 3 months are candidates for ICS step-down. Children approaching adolescence may experience spontaneous improvement in asthma severity — the majority of childhood asthma improves substantially by late adolescence, and some children can stop ICS entirely with close monitoring.