Fever in Children Algorithm

The full reasoning pathway — use the NICE traffic-light system to identify the unwell child and the must-not-miss diagnoses (sepsis, meningitis, leukaemia) before reassuring the common viral illness; treat the focus, refer and safety-net the parents.StartDecisionInvestigateActionReferStop / Admit

PresentationFever in a child

Age, duration, focus, fluid intake/output, activity/alertness. Full obs (incl. RR, HR, cap refill, temp), rash (glass test), hydration. Apply the NICE traffic-light assessment.

Step 1 · Safety — red / sepsis / meningitis (NG143/NG240)High-risk features?

Non-blanching/petechial rash, mottled/blue, looks unwell, reduced consciousness
Weak/high-pitched/continuous cry, bulging fontanelle, neck stiffness, focal neurology, status
Grunting, RR >60, prolonged cap refill, reduced skin turgor
<3 months + temp ≥38, or 3–6 months + ≥39 → high-risk

RED — high-risk

Stop · 999Emergency

Suspected meningitis/meningococcal sepsis → 999. Give pre-hospital IM/IV benzylpenicillin (or ceftriaxone) if a non-blanching rash is present or transfer is delayed — but do not delay transfer. Any febrile infant <3 months → urgent paediatric assessment.

GREEN/AMBER — assess

Step 2 · InvestigateFind the focus

Always dip the urine (UTI is easily missed); examine ears/throat/chest; consider CRP/FBC/cultures in amber or <3 months per protocol. Undress fully to look for a rash.

Step 3 · which cause?

Self-limiting viral

Commonest

URTI, viral exanthem (roseola, hand-foot-mouth), green-category child with a clear viral focus.

Treatable bacterial focus

Treat

Otitis media, tonsillitis, UTI (urine dip), pneumonia; treat per focus.

Serious / must-not-miss

Don't miss

Meningococcal sepsis, meningitis, leukaemia (petechiae/pallor/hepatosplenomegaly), Kawasaki (≥5 days fever), osteomyelitis/septic arthritis, appendicitis.

Step 7 · manage

Step 7 · Action — by categoryTreat the cause, advise the parent

Viral (green): antipyretics for distress, not for the temperature itself (don't alternate paracetamol/ibuprofen routinely), encourage fluids, manage at home with safety-netting.
Bacterial focus: appropriate antibiotic (e.g. amoxicillin for UTI/pneumonia per local guidance) + review.
Amber: consider observation, investigations, a safety-net plan or a period of review.
Red: emergency treatment + admission.

Step 6 · escalation thresholds

Step 6 · ReferEscalation thresholds

999 red-flag/sepsis/meningitis.
2WW · NICE NG12 (children) unexplained petechiae + fever, or hepatosplenomegaly / generalised lymphadenopathy → very urgent FBC + immediate paediatric referral (leukaemia).
Paediatrics all infants <3 months with fever, amber features not settling, fever ≥5 days (Kawasaki), or diagnostic uncertainty.

Step 8 · home care & prevention

Step 8 · Home care & preventionParent education

Fluids and antipyretics for distress (not to prevent febrile convulsions — they don't); avoid over-wrapping/tepid sponging · ensure immunisations up to date · hand hygiene · clear written "when to worry" advice and where to seek help out of hours · check the child can maintain hydration.

Step 9 · safety-net

Step 9 · Safety-net & follow-upTell parents exactly when to return

Call 999 / return immediately if a non-blanching rash, the child becomes less responsive/floppy, has a fit, difficulty breathing, looks mottled/blue, or won't take fluids/has reduced wet nappies. Review if fever persists >5 days or no focus emerges. Document the traffic-light category and the advice given.

⚠️ Always undress and examine for a non-blanching rash — and any child with unexplained petechiae plus fever needs a very urgent FBC and immediate paediatric referral to exclude leukaemia and meningococcal sepsis. Always dip the urine.

Safety

Red Flags — Exclude life-threatening causes immediately

Done

Call 999 or send to ED without delay if ANY red flag present. Do not investigate — act.

Non-blanching rash / petechiae May indicate meningococcal sepsis → 999 IV benzylpenicillin if ≥1 month before transfer

Meningism Neck stiffness, photophobia, Kernig's / Brudzinski's sign → 999 Bacterial meningitis

Bulging fontanelle In infants — raised ICP → 999

Septic shock signs Mottled / pale / blue skin, cap refill >2s, hypotension, lethargy → 999

Fever <3 months + temp ≥38°C High risk of serious bacterial infection → 999 or same-day ED

Seizure / status epilepticus First febrile seizure >5 min or focal → 999

Altered consciousness / inconsolable GCS drop, persistent high-pitched cry, not rousable → 999

Respiratory distress Grunting, nasal flaring, SaO₂ <95%, cyanosis → 999

Fever >5 days Consider Kawasaki disease — same-day paediatric review

Immunocompromised child On steroids / chemotherapy / asplenic with fever → Same-day ED

Features of leukaemia Fever + unexplained pallor, persistent fatigue, bruising/bleeding, petechiae, generalised lymphadenopathy or hepatosplenomegaly → Very urgent FBC (≤48h) + immediate paediatric referral (NICE NG12 — children & young people)

Fever is the commonest presenting complaint in paediatric primary care but 1–3% of febrile children have a serious bacterial infection (SBI). The NICE traffic light system (NG143) stratifies risk; red features mandate immediate action before any other assessment.

Meningococcal disease has a case fatality of ~10% — pre-hospital IM benzylpenicillin (300mg <1yr, 600mg 1–9yr, 1.2g ≥10yr) reduces mortality and should not delay transfer.

Infants under 3 months have immature immune responses; even low-grade fever carries a 10–15% risk of SBI. Febrile infants <28 days should always be admitted.

Diagnose

Assess — NICE Traffic Light System (Green / Amber / Red)

Done

Apply the NICE NG143 traffic light tool across colour, activity, respiratory, hydration, and other features.

🟢 GREEN — Low risk

Normal colour; responds normally; normal cry; moist mucous membranes; no red/amber features → Home with safety-net

🟡 AMBER — Intermediate

Pallor, decreased activity, prolonged febrile (>5 days), limb swelling, rigors, new lump >2cm → Urgent GP review or same-day

🔴 RED — High risk

Any red flag from Step 1 → 999 / immediate ED

Temperature

Record axillary (add 0.5°C), tympanic, or rectal. Fever = ≥38°C. Height of fever does not reliably predict SBI.

Duration

Fever >5 days → Kawasaki screen (see Step 6). Document carefully — parents' history is key.

Focus found?

URTI, otitis media, tonsillitis, UTI, pneumonia → likely source. No focus = higher SBI risk.

The NICE traffic light system has a sensitivity of ~90% for SBI when red features are present. However specificity is lower — amber features require clinical judgement. No single feature is pathognomonic; the gestalt of the unwell child matters.

Temperature height alone is a poor predictor of SBI. A child with 39°C who is alert, playful and well-perfused is far lower risk than a lethargic child with 38.2°C.

Diagnose

Age-specific risk stratification

Done

Age is the strongest independent risk modifier for serious infection in febrile children.

<28 days

All febrile neonates → 999 / immediate admission regardless of appearance. Risk of SBI ~30%. Group B Strep, E. coli, Listeria.

1–3 months

Temp ≥38°C → same-day ED assessment. NICE recommends LP, blood/urine cultures, IV antibiotics if unwell.

3–6 months

Temp ≥39°C without source → urgent review. High risk of UTI, occult bacteraemia.

6 months – 5 years

Viral illness most likely (>95% of cases). Target amber/red features. MSU if any urinary symptoms or no source in girls <2yr or uncircumcised boys <1yr.

5–12 years

Same amber/red framework. Consider EBV, mycoplasma if prolonged or with pharyngitis + rash.

Immunocompromised

Any fever → same-day ED regardless of age. Neutropenic sepsis kills within hours.

Age-based thresholds reflect immuno-developmental physiology. Neonates lack maternal IgG for many pathogens and have immature neutrophil function. The NICE NG143 thresholds are derived from prospective cohort studies of 5000+ febrile children.

UTI is the most common SBI in children 1–24 months and is easily missed — it causes no localising symptoms in infants. A clean-catch urine dipstick (leucocyte esterase + nitrites) has 88% sensitivity; send MSU if positive or clinical suspicion.

Diagnose

Targeted Examination — systematic head-to-toe

Done

Full examination every time. Never assume it's a simple viral illness without excluding other sources.

General impression

Responds to parent, maintains eye contact, consolable → low risk. Lethargic, glassy-eyed, high-pitched cry → high risk.

Skin

Rash: blanching (viral) vs non-blanching (petechiae/purpura → meningococcal). Jaundice in neonate = urgent. Scarlatiniform rash = strep.

ENT

Ears: erythematous TM / effusion (AOM). Throat: tonsillar exudate (use Centor/FeverPAIN). Lymphadenopathy: anterior cervical = local infection; generalised = EBV/malignancy.

Respiratory

RR (>60 in <2mo, >50 in 2–12mo, >40 in 1–5yr = abnormal). Recession, nasal flaring, grunting, wheeze, focal crackles.

Abdomen

Tenderness, guarding, rebound → surgical emergency. Right iliac fossa = appendicitis (peak 6–10yr). Hepatosplenomegaly = EBV.

Fontanelle

Infants only — bulging = raised ICP → 999. Sunken = dehydration.

Perfusion

Cap refill <2s (central), warm peripheries, normal HR for age, normal BP. Tachycardia alone can be fever-driven but persisting after antipyretic is concerning.

Urine

Dipstick in all febrile children <2yr without source, all girls <5yr, all boys <1yr. Offensive urine / frequency = UTI until proven otherwise.

Up to 20% of febrile children with a clinical diagnosis of "viral URTI" have a concomitant UTI. Systematic examination changes management in approximately 30% of cases where a source is found.

The "general impression" — how sick does this child look? — remains the highest-yield clinical decision tool and is what parents mean when they say "they just don't seem right." Trust parental concern: it correlates with illness severity.

Diagnose

Investigations — targeted, not blanket

Done

Most febrile children (>95%) require NO investigations in primary care. Investigate only when it will change management.

Urine dipstick / MSU

First-line All children <2yr without source. Girls <5yr. Boys <1yr. Send MSU if dipstick +ve or strong clinical suspicion. Do not delay treatment for result.

Throat swab

Only if GAS strongly suspected (FeverPAIN ≥4 or Centor ≥3) and antibiotic prescribing considered. Routine swabs not recommended — most sore throats are viral.

FBC + CRP

Consider if amber or persistent fever >5 days. WBC >15 or CRP >80 raises SBI risk but not diagnostic. Do not rely on WBC alone.

Blood cultures

Hospital only — not in primary care. Taken before IV antibiotics.

COVID/RSV/flu swab

Consider in community if affects isolation / cohorting decision or in at-risk groups. Not routine for every febrile child.

Kawasaki screen

If fever >5 days: FBC, CRP, ESR, LFTs, ECHO referral. Kawasaki criteria: fever ≥5 days + ≥4 of: conjunctivitis, rash, lymphadenopathy, strawberry tongue, hand/foot changes.

Do NOT order

Routine CXR in primary care. Blood cultures in community. LP outside hospital. Repeat bloods within 24hrs unless clinical deterioration.

CRP has a sensitivity of ~80% for SBI at a threshold of 80mg/L but misses ~20% of cases. It should be used to support, not replace, clinical judgement. A normal CRP does not rule out SBI in the first 12 hours of illness.

Urine testing is the most impactful investigation in primary care — UTI is the most common SBI, missed in 50% of infants because symptoms are non-specific. A clean-catch dipstick takes 2 minutes and changes management.

Refer

Referral Criteria — who needs hospital assessment today?

Done

999

Any Step 1 red flag. Non-blanching rash, seizure, altered consciousness, respiratory failure, septic shock signs, neonate with fever.

Same-day ED

Age <3 months with fever ≥38°C. Amber NICE features + no improvement after antipyretic. Immunocompromised. Unable to tolerate oral fluids. Suspected appendicitis.

Same-day paeds

Fever >5 days (Kawasaki screen). Suspected septic arthritis / osteomyelitis (limb swelling + fever + refusal to weight-bear). Suspicious rash + fever (parvovirus B19, HHV-6, varicella complications).

Urgent GP / OOH

Parental concern overriding your assessment — trust it. No improvement after 48hrs. New symptoms developing. Unable to assess adequately.

Primary care manage

Green NICE features. Clear viral source (URTI, hand-foot-mouth). Adequate fluid intake. Parent confident with safety-net. Age >3 months.

Kawasaki disease

Fever ≥5 days + classic features → same-day paediatric referral. Missing Kawasaki = coronary aneurysm risk. IVIG within 10 days reduces aneurysm risk from 25% to <5%.

The decision to admit is the most important clinical decision in paediatric fever. Under-referring risks missing SBI; over-referring exposes children to nosocomial infection, unnecessary procedures, and parental anxiety. The NICE traffic light system guides but does not replace clinical judgement.

Parental concern is a validated risk factor for SBI independent of clinical findings. Studies show parents correctly identify deterioration before clinicians in 70% of cases.

Treat

Treatment — antipyretics, antibiotics, and supportive care

Done

Antipyretics treat discomfort — they do not prevent febrile seizures or alter disease course.

Discomfort / distress

Paracetamol 1st line

15mg/kg/dose PO 4–6 hourly. Max 4 doses/24h. From birth. Syrup / suppository / dispersible.

If paracetamol insufficient

Ibuprofen 2nd line

5–10mg/kg/dose PO 6–8 hourly. Age ≥3 months, weight ≥5kg. Avoid if dehydrated, renal impairment, varicella.

Alternating (controversial)

Alternate paracetamol + ibuprofen

Only if fever causing significant distress and neither alone effective. Not recommended routinely — risk of dosing errors. NICE does not recommend as standard.

Antibiotics — AOM

Amoxicillin 40mg/kg/day in 3 divided doses for 5 days. If <2yr bilateral or with perforation. Watchful waiting 48–72hr for mild AOM >2yr. Allergy: clarithromycin.

Antibiotics — URTI

Do not prescribe antibiotics for viral URTI. Delayed prescription acceptable if parents insist + amber features. Phenoxymethylpenicillin for confirmed GAS tonsilitis 10 days.

Antibiotics — UTI

Trimethoprim 4mg/kg BD x 7 days (1st line if local sensitivity allows). Nitrofurantoin 1mg/kg QDS x 7 days alternative. Send MSU before starting. Children <3months → IV in hospital.

Antibiotics — Pneumonia

Amoxicillin 40–90mg/kg/day in 3 doses x 5 days. Atypical: add clarithromycin if school-age + dry cough. Severe: hospital.

Pre-transfer Benzylpenicillin

If meningococcal disease suspected: <1yr 300mg IM/IV. 1–9yr 600mg. ≥10yr 1.2g. Give before 999 transfer. Do not delay 999 call to give.

Antipyretics reduce fever by 1–2°C and improve child comfort but do NOT reduce risk of febrile seizure recurrence (Cochrane 2017). Do not wake a sleeping child to give antipyretics. Fever itself is not harmful — it is part of the immune response.

Antibiotic prescribing for viral URTI is the commonest source of unnecessary antibiotic use in paediatrics and drives resistance. The RCGP TARGET Toolkit supports delayed prescription strategies. NNT to prevent one case of otitis media with antibiotics for URTI = 6000.

For UTI: trimethoprim resistance is rising (>30% in some areas). Check local antibiogram. Send MSU before treatment — culture results guide switch if no improvement at 48hrs.

Lifestyle

Supportive Care & Parental Guidance

Done

Clear verbal and written advice to parents reduces re-attendance, prevents complications, and builds confidence.

Hydration — key priority Encourage regular fluids: breast milk / formula in infants; water, diluted squash, oral rehydration solution in older children. Wet nappies / regular urination = adequate hydration.

Dress lightly Remove excess clothing. Tepid sponging is NOT recommended — NICE 2023 advises against. Room temperature 18–21°C. Avoid over-bundling.

School / nursery exclusion Exclude until fever-free for 24hrs (48hrs for GI illness). No need to exclude for mild URTI without fever. Inform school of Kawasaki / invasive GAS if applicable.

Vaccination check Is child up to date? Fever within 24–48hrs of MenACWY / PCV / MMR is common and expected. Fever >48hrs post-vaccine or >39.5°C → assess as per usual pathway.

Avoid aspirin Never give aspirin to children under 16 (Reye's syndrome risk) — except under specialist guidance in Kawasaki disease.

Written safety-net Provide written advice: when to call 999, when to re-attend. Consider NHS 111 leaflet. "Fever in children" NICE patient leaflet available online.

Dehydration is the primary complication of fever in children and is prevented by consistent oral fluid intake rather than temperature management. Signs of dehydration (dry mucous membranes, sunken eyes, reduced urine output) should trigger urgent reassessment.

Parental anxiety is the primary driver of re-consultation for fever. Studies show that written safety-net advice reduces emergency re-attendance by 40% compared to verbal advice alone. The NICE "fever in under 5s" patient information leaflet is freely available and evidence-based.

Safety

Follow-up, Safety-Netting & Monitoring

Done

24–48 hrs

Review if amber features present. Check urine result if sent. Confirm child improving. If worsening → reassess urgently.

48–72 hrs

If no improvement in well child with presumed viral illness → repeat assessment. Consider delayed antibiotic prescription to open. Check for new focus.

Fever >5 days

Kawasaki screen — do not miss. FBC, CRP, ESR, LFTs. Refer paediatrics same-day if ≥3 Kawasaki criteria alongside fever.

UTI follow-up

Renal USS within 6 weeks for all UTIs in children <6 months. All febrile UTIs in under 3s → urgent renal USS <2 weeks. DMSA / MAG3 if recurrent UTI.

Call 999 if:

Rash becomes non-blanching. Seizure. Child becomes unresponsive. Difficulty breathing. Blue around lips.

Same-day if:

No urine output for 8 hrs. Unable to keep fluids down. Fever returns after 24hr gap. Parent very concerned about behaviour change. New or worsening symptoms.

Febrile seizure follow-up

If first simple febrile seizure recovered → no urgent investigation needed in most cases. Advise parents on seizure first aid. EEG not routinely indicated for simple FS. Review 1–2 weeks.

Safety-netting reduces medicolegal risk and improves outcomes. NICE NG143 specifies that all children discharged from primary care with fever must receive written or verbal safety-net advice. Document that this was given.

Renal tract imaging after UTI detects vesicoureteric reflux (present in 30% of children with febrile UTI) and renal scarring. Missed reflux leads to recurrent UTIs and chronic kidney disease. NICE recommends USS within 6 weeks for all febrile UTIs in children under 6 months and under 3 years with unusual organisms or recurrence.