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Key Learning Points: NICE Fever in Under 5s

Dr Nazia Hussain Identifies Five Key Learning Points for Primary Care from the Updated NICE Guideline on the Assessment and Initial Management of Fever in Children Under 5 Years Old

Read This Article to Learn More About:
  • recognising when symptoms may indicate Kawasaki disease
  • using the traffic light system to determine the risk of serious illness
  • providing appropriate safety netting advice.

Find implementation actions for STPs and ICSs at the end of this article

NICE Guideline (NG) 143 on Fever in under 5s: assessment and initial management1 was published in November 2019 and supersedes Clinical Guideline (CG) 160, published in 2013. The updated guideline aims to improve clinical assessment and help healthcare professionals diagnose serious illness, such as Kawasaki disease, among children who present with fever.

Fever usually indicates underlying infection. For the purposes of this guideline, fever was defined as an elevation of body temperature above the normal daily variation.1 In more practical terms, a temperature above 38°C is considered abnormal.2

Fever is a common presentation in young children and is a cause of concern for parents and carers. Around 20 to 39% of parents report feverish illness each year in young children.3 Despite advances in healthcare, infection remains a leading cause of death in children under the age of 5 years in the UK.1,4

Fever can present a diagnostic conundrum early on in the course of illness, as is often the case with presentations in primary care. Fever is mostly caused by a self-limiting viral infection, but it may signal serious bacterial infection, such as meningitis or pneumonia. Often, there is no obvious cause of fever despite careful assessment.1

Further difficulties in assessing fever in young children include:

  • the child not being able to communicate their symptoms—practitioners must rely upon the observations and concerns of parents or carers
  • the clinical picture is often changing rapidly—it can be challenging to base a decision on only 10 minutes of consulting time
  • the child’s behaviour may not reflect the seriousness of their illness—the child who seemed to be alert and playful may deteriorate seriously within hours, whereas the clingy, quiet child may become more active after being treated with anti-pyretic medications.

NICE Guideline 143 should be read in conjunction with the following guidelines:

What Has Been Updated?

Following an evidence review, NICE has made new recommendations on assessment for Kawasaki disease, which are discussed in key learning point 1, below. The remaining four learning points summarise other important areas relevant to general practice, which have not been reviewed and updated in the 2019 guideline.

1. Be Aware of Kawasaki Disease

Kawasaki disease is an acute febrile illness of unknown aetiology that mainly affects children aged under 5 years. Although rare, it is the commonest cause of acquired heart disease in children in the UK, with an incidence estimated to be 9.1 per 100,000 in children under 5.11 The illness can present with a variety of clinical features, making it difficult to distinguish from other causes of self-limiting febrile illness. There is currently no diagnostic test for Kawasaki disease. The American Heart Association’s clinical diagnostic criteria for Kawasaki disease are:12

  • persistent fever (for 5 days or longer), plus at least four of the following:
    • changes in extremities
    • polymorphous rash
    • bilateral conjunctivitis
    • oral cavity involvement
    • cervical lymphadenopathy.

The underlying pathology is a vasculitis from which the coronary arteries are particularly susceptible to damage. Coronary artery aneurysms occur in 15–25% of cases.12 Treatment with intravenous immunoglobulin within the first 10 days reduces the risk of coronary artery aneurysms by 26% compared with treatment with placebo.13 Thus, a delayed diagnosis may result in a missed opportunity to prevent serious cardiac complications.

NICE recommends that practitioners should be aware of the possibility of Kawasaki disease in children with fever that has lasted 5 days or longer. Additional features of Kawasaki disease may include [see NG143; 1.2.26]:1

  • bilateral conjunctival injection without exudate
  • erythema and cracking of lips; strawberry tongue; or erythema of oral and pharyngeal mucosa
  • oedema and erythema in the hands and feet
  • polymorphous rash
  • cervical lymphadenopathy.

Ask parents or carers about the presence of these features since the onset of fever, because they may have resolved by the time of assessment [see NG143; 1.2.27]. Be aware that children under 1 year old may present with fewer clinical features of Kawasaki disease in addition to fever, but may be at higher risk of coronary artery abnormalities than older children [see NG143; 1.2.28].1

Unfortunately, there is no existing evidence on how accurate most signs or symptoms are at confirming or excluding Kawasaki disease in a group of children with fever. The guideline committee made a research recommendation for a diagnostic accuracy study in this area to allow more specific recommendations to be made when the guideline is next updated.1

In the previous version of the guideline (CG160), it was recommended that Kawasaki disease should be considered when a child had a fever lasting more than 5 days and had four of the five principal features specified by the American Heart Association diagnostic criteria. However, the evidence from case-series suggested that often fewer than four features are present early in the course of the illness, and some children may have ‘incomplete’ Kawasaki disease, in which fewer than four features are present throughout the course of the illness. Because of this, clinicians should consider Kawasaki disease in all children who have a fever lasting 5 days or longer, even when no additional features are present, and should be aware of the principal features of Kawasaki disease that would increase the probability of a Kawasaki disease diagnosis.1

The new recommendations should prompt clinicians to think about Kawasaki disease in children with fewer clinical features, which may result in more children being referred for assessment in secondary care. However, prompt identification and treatment of children with Kawasaki disease should reduce the number of children with long-term cardiac complications, which in turn should reduce long-term costs for the NHS.

2. Measure the Child’s Temperature Accurately

In infants under the age of 4 weeks, measure body temperature with an electronic thermometer in the axilla [see NG143; 1.1.2].1 In children aged 4 weeks to 5 years, measure body temperature by one of the following methods [see NG143; 1.1.3]:1

  • electronic thermometer in the axilla
  • chemical dot thermometer in the axilla
  • an infra-red tympanic thermometer.

Parental perception of fever should be seen as valid and taken seriously [see NG143; 1.1.6].1

Children younger than 3 months with a temperature of 38°C or higher are in a high-risk group for serious illness and children aged 3–6 months with a temperature of 39°C or higher are in at least an intermediate-risk group for serious illness [see NG143; 1.2.12 and 1.2.13].1

In children older than 6 months, do not use height of body temperature alone to identify those with serious illness [see NG143; 1.2.11].1 When a child has been given antipyretics, do not rely on a decrease or lack of decrease in temperature to differentiate between serious and non-serious illness [see NG143; 1.4.8].Do not use duration of fever to predict the likelihood of serious illness; however, children with a fever lasting 5 days or longer should be assessed for Kawasaki disease [see NG143; 1.2.14].1

3. Document a Thorough Examination of the Child

In primary care, children often become shy and fractious in the consulting room. If possible, it can be very helpful to observe them in the waiting area; seeing a child playing and running around can provide reassurance that the diagnosis is a simple viral illness. If there is doubt, invite them to return for a re-assessment later the same day, or on the next day.

Practitioners should perform examinations opportunistically—examine the chest when the child is settled at the start and leave more distressing examinations, like that of the throat, until the end. Ensure adequate exposure of the skin surface to be confident that there are no rashes.

First, identify any immediately life-threatening features, including compromise of the airway, breathing, or circulation; decreased level of consciousness; and consider the possibility of sepsis [see NG143; 1.2.1 and 1.2.2].1

Children with fever should then be assessed for the presence or absence of symptoms and signs that can be used to predict the risk of serious illness using the traffic light system (see Table 1) [see NG143; 1.2.3].Children with fever and any of the symptoms or signs in the ‘Red—high risk’ column should be recognised as being at high risk. Children with fever and any of the symptoms or signs in the ‘Amber—intermediate risk’ column and none in the red column should be recognised as being at intermediate risk. Children with symptoms and signs in the ‘Green—low risk’ column and none in the amber or red columns are at low risk of serious illness.1

When assessing children with learning disabilities, it is important to take the individual child’s learning disability into account when interpreting their symptoms using the traffic light table [see NG143; 1.2.4].1

Measure and record temperature, heart rate, respiratory rate, and capillary refill time as part of the routine assessment of a child with fever [see NG143; 1.2.8].1

Table 1: Traffic Light System for Identifying Risk of Serious Illness1

  Green—Low Risk Amber—Intermediate Risk Red—High Risk
Colour (of skin, lips or tongue) 
  • Normal colour
  • Pallor reported by parent/carer
  • Pale/mottled/ashen/blue
  • Responds normally to social cues
  • Content/smiles
  • Stays awake or awakens quickly
  • Strong normal cry/not crying
  • Not responding normally to social cues
  • No smile
  • Wakes only with prolonged stimulation
  • Decreased activity
  • No response to social cues
  • Appears ill to a healthcare professional
  • Does not wake or if roused does not stay awake
  • Weak, high-pitched or continuous cry
Respiratory  --
  • Nasal flaring
  • Tachypnoea: respiratory rate
    • >50 breaths/minute, age 6–12 months;
    • >40 breaths/minute, age >12 months
  • Oxygen saturation ≤95% in air
  • Crackles in the chest
  • Grunting
  • Tachypnoea: respiratory rate >60 breaths/minute
  • Moderate or severe chest indrawing
Circulation and hydration
  • Normal skin and eyes
  • Moist mucous membranes
  • Tachycardia:
    • >160 beats/minute, age <12 months
    • >150 beats/minute, age 12–24 months
    • >140 beats/minute, age 2–5 years
  • Capillary refill time ≥3 seconds
  • Dry mucous membranes
  • Poor feeding in infants
  • Reduced urine output
  • Reduced skin turgor
  • None of the amber or red symptoms or signs
  • Age 3–6 months, temperature ≥39°C
  • Fever for ≥5 days
  • Rigors
  • Swelling of a limb or joint
  • Non-weight bearing limb/not using an extremity
  • Age <3 months, temperature ≥38°C*
  • Non-blanching rash
  • Bulging fontanelle
  • Neck stiffness
  • Status epilepticus
  • Focal neurological signs
  • Focal seizures
* Some vaccinations have been found to induce fever in children aged under 3 months
This traffic light table should be used in conjunction with the recommendations in the NICE guideline on fever in under 5s.
© NICE 2019. Fever in under 5s: assessment and initial management. Available from: All rights reserved. Subject to Notice of rights. NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication. See for further details.

4. Establish a Working Diagnosis

The history and examination should help form a working diagnosis of the cause of the fever. Explore any unwell contacts at home, nursery/school, and any recent travel abroad (e.g. malaria endemic regions). Consider the possibility of imported infections according to the region visited [see NG143; 1.2.29].1

It may be difficult to establish the cause of fever, especially in the early stages of febrile illness. The traffic light system can help triage the next course of action [see NG143; 1.4.2–1.4.5]:1

  • children with any features of a life-threatening illness—refer immediately via 999
  • children with ‘red’ features (not immediately life-threatening)—refer urgently to a paediatric specialist
  • children with ‘amber’ features and no diagnosis—provide parents or carers with a ‘safety net’ or refer to specialist paediatric care for further assessment
  • children with ‘green’ features—manage at home with appropriate safety-netting.

See key learning point 5, below, for further recommendations on safety-netting.

The principles of assessing the risk of serious illness can also be applied to telephone consultations. There should be a low threshold for arranging face-to-face reviews and this should be guided by the traffic light system [see NG143; 1.3.2–1.3.5]:1

  • children with features of a life-threatening illness—refer immediately via 999
  • children with any ‘red’ features—arrange a face-to-face review by a medical practitioner within 2 hours
  • children with ‘amber’ features but no ‘red’ features—arrange for them to be assessed by a medical practitioner in a face-to-face setting in an appropriate time-frame. Generally, it is sensible for the child to attend as soon as possible
  • children with ‘green’ features but no ‘amber’ or ‘red’ features—manage at home with appropriate safety-netting.

Clinical judgement is vital; if a child looks unwell or there is significant parental anxiety, it is better to refer these children into hospital for assessment and a period of clinical observation. Not all children will fit perfectly into one category.

Look for a source of fever and check for the presence of symptoms and signs that are associated with specific diseases (see Table 2) [see NG143; 1.2.17].These specific diseases (other than Kawasaki disease) include bacterial meningitis, herpes simplex encephalitis, meningococcal disease, pneumonia, septic arthritis, and urinary tract infection.

Table 2: Summary Table for Symptoms and Signs Suggestive of Specific Diseases1

Diagnosis to be Considered Symptoms and Signs in Conjunction with Fever
Meningococcal disease

Non-blanching rash, particularly with 1 or more of the following:

  • an ill-looking child
  • lesions larger than 2 mm in diameter (purpura)
  • capillary refill time of ≥3 seconds
  • neck stiffness
Bacterial meningitis

Neck stiffness

Bulging fontanelle

Decreased level of consciousness

Convulsive status epilepticus

Herpes simplex encephalitis

Focal neurological signs

Focal seizures

Decreased level of consciousness


Tachypnoea (respiratory rate >60 breaths/minute, age 0–5 months; >50 breaths/minute, age 6–12 months; >40 breaths/minute, age >12 months)

Crackles in the chest

Nasal flaring

Chest indrawing


Oxygen saturation ≤95%

Urinary tract infection


Poor feeding



Abdominal pain or tenderness

Urinary frequency or dysuria

Septic arthritis

Swelling of a limb or joint

Not using an extremity

Non-weight bearing

Kawasaki disease [2019]

Fever for 5 days or longer and may have some of the following:

  • bilateral conjunctival injection without exudate
  • erythema and cracking of lips; strawberry tongue; or erythema of oral and pharyngeal mucosa
  • oedema and erythema in the hands and feet
  • polymorphous rash
  • cervical lymphadenopathy
© NICE 2019. Fever in under 5s: assessment and initial management. Available from: All rights reserved. Subject to Notice of rights. NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication. See for further details.

5. Provide Appropriate Management and Safety-netting Advice

Antipyretic agents do not prevent febrile convulsions and should not be used specifically for this purpose. Tepid sponging is not recommended, and children should not be underdressed or over-wrapped [see NG143; 1.6.1–1.6.3].1

When using paracetamol or ibuprofen in children with fever [see NG143; 1.6.6]:1

  • continue only as long as the child appears distressed
  • consider changing to the other agent if the child’s distress is not alleviated
  • do not give both agents simultaneously
  • only consider alternating these agents if the distress persists or recurs before the next dose is due.

Safety-netting advice is a vital part of any consultation. This advice should include one or more of the following [see NG143; 1.4.4]:1

  • providing verbal and/or written information on warning symptoms and how further healthcare can be accessed
  • arranging further follow-up at a specified time and place
  • liaising with other healthcare professionals, including out-of-hours providers, to ensure direct access for the child if further assessment is required.

Parents or carers should be advised [see NG143; 1.7.2]:1

  • to encourage regular fluids and consider seeking advice if they detect the following signs of dehydration:
    • sunken fontanelle
    • dry mouth
    • sunken eyes
    • absence of tears
    • poor overall appearance
  • how to identify a non-blanching rash
  • to check their child during the night
  • to keep their child away from nursery or school while the child’s fever persists but to notify the school or nursery of the illness.

Parents or carers should seek medical attention if [see NG143; 1.7.3]:1

  • the child has a fit
  • the child develops a non-blanching rash
  • they feel the child is less well or they are more worried than when they previously sought advice
  • the fever lasts 5 days or longer
  • they are distressed, or concerned that they are unable to look after their child.


Fever in children under 5 years is a common presentation to primary care with a wide variety of causes. The traffic light system can help assess the risk of serious illness. Be aware of Kawasaki disease in children with fever for 5 days or longer. Children with Kawasaki disease may have few additional clinical features to fever, especially children under 1 year.

Dr Nazia Hussain

GP, Gwent

Member of the NG143 Guideline Development Group

Implementation Actions for STPs and ICSs

Written by Dr David Jenner, GP, Cullompton, Devon

The following implementation actions are designed to support STPs and ICSs with the challenges involved with implementing new guidance at a system level. Our aim is to help you consider how to deliver improvements to healthcare within the available resources.

  • Establish a multi-professional team led by paediatricians to consider these guidelines and the challenges of applying them in both primary and secondary care
  • Review any triage systems in operation by GP, out-of-hours providers, and 111 services to ensure that they have been updated to accommodate these guidelines
  • Ensure any digital consultation tools are also compliant with these guidelines, including those using artificial intelligence or ‘chatbots’
  • Consider providing (or signposting to) online symptom checkers for members of the public to access, and advertise their presence on other nationally provided services such as NHS 111 online
  • Publish and disseminate the useful ‘traffic light’ guidance charts to all frontline health providers, including pharmacies.

STP=sustainability and transformation partnership; ICS=integrated care system

The guideline discussed in this article was produced by the Guideline Updates Team for the National Institute for Health and Care Excellence (NICE). The views expressed in this article are those of the author and not necessarily those of NICE.

National Institute for Health and Care Excellence (2019). Fever in under 5s: assessment and initial management. Available from