Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Fever or infection in an immunocompromised child
Paediatrics and child health · UK scope · Sources checked 27 Aug 2026 · Clinical review pending
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Suspected neutropenic sepsis
After anticancer treatment, NICE defines neutropenic sepsis as an absolute neutrophil count of 0.5 × 10^9/L or lower with temperature above 38°C or other signs or symptoms consistent with clinically significant sepsis. Fever may be absent during profound immunosuppression, so new deterioration, rigors, hypotension, respiratory change or line symptoms are also emergencies.
Action: Transfer urgently to the child's designated oncology or specialist centre, assess ABCDE and obtain cultures and initial blood tests without delaying antimicrobials. Give immediate intravenous empirical therapy; NICE recommends piperacillin with tazobactam monotherapy unless patient-specific or local microbiological contraindications apply. Involve senior paediatrics, oncology or immunology and critical care early, and follow the child's emergency plan and local resistant-organism pathway.
Overview
Recognise infection despite muted signs, treat febrile neutropenia as an emergency, tailor investigations and antimicrobials to the immune defect, and escalate deterioration without waiting for microbiological proof.
An immunocompromised child has impaired defence because of disease or treatment. Important groups include anticancer chemotherapy, haematopoietic or solid-organ transplant, severe primary immunodeficiency, HIV, biologic or high-dose steroid treatment, asplenia and complement inhibition.
The affected immune component predicts organisms. Neutropenia increases rapidly invasive Gram-negative and Gram-positive bacterial infection and fungal disease; T-cell defects increase viral, fungal and intracellular pathogens; antibody or splenic defects increase encapsulated bacteria.
Mucosal damage and central venous access add separate risks. Chemotherapy injures gut epithelium and permits endogenous flora to cross into blood, while a catheter bypasses skin and can support biofilm infection.
Signs can be muted. Profound neutropenia limits pus, steroid treatment reduces inflammation and fever, and transplant medicines alter organ response. A child or parent reporting that something is wrong may therefore precede an abnormal examination.
Practice
Two practice questions
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Paediatrics and child healthOriginal SBA
Immediate neutropenic-sepsis treatment
A 6-year-old receiving chemotherapy has a temperature of 38.2°C, neutrophils of 0.3 × 10^9/L and no focal source. The child is haemodynamically stable. What is the best initial management?
Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources
Sources and review status
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
Piperacillin with tazobactam SmPCPaediatric and adolescent neutropenic-fever dosing, infusion, renal adjustment and safety information.
Green Book chapter 7 underlying conditionsImmune-risk categories and protection of immunosuppressed, asplenic and complement-deficient children and their close contacts.
Use the child's specialist emergency letter where available, but do not delay generic sepsis care while searching for it. Obtain treatment phase, date of last chemotherapy, expected neutrophil nadir, line type, prophylaxis, allergies and previous resistant isolates.
NICE uses temperature above 38°C rather than requiring 38.5°C in its neutropenic-sepsis definition after anticancer treatment. Local paediatric oncology pathways may deliberately use an equally or more sensitive contact threshold.
Assess ABCDE and obtain current weight. Look carefully at mouth and mucosa, skin and catheter, lungs, abdomen and perianal symptoms, urine, joints and nervous system, but avoid rectal temperature, suppositories and digital rectal examination during neutropenia.
The first antimicrobial dose is time critical. Cultures improve targeting, but inability to obtain a peripheral specimen or central-line access problems must not delay treatment in a deteriorating child.
Piperacillin with tazobactam covers many expected Gram-negative, anaerobic and Gram-positive organisms and is recommended as initial monotherapy by NICE. Previous resistant colonisation, severe beta-lactam allergy or a specific focus changes the regimen through local microbiology advice.
Routine aminoglycoside addition increases toxicity without sufficient benefit, and a glycopeptide is not automatically needed for every central line. Shock, skin or line infection, known resistant Gram-positive colonisation and culture results are examples that may justify escalation.
Fever can persist despite appropriate treatment because of delayed inflammatory resolution, viral disease, fungal infection, drug fever, malignancy or tissue injury. Change therapy for a new clinical or microbiological reason, not the temperature curve alone.
Risk stratification is dynamic. NICE recommends a validated risk-assessment tool within 24 hours for patients having anticancer treatment, with daily reassessment; the rule must be validated for children and the local service.
Only a specialist team should classify a child as low risk for outpatient treatment. The family needs reliable transport, telephone access, understanding, rapid return, a responsible service and no evolving physiological or social concern.
Prolonged profound neutropenia increases invasive mould and yeast risk. Persistent or recurrent fever prompts infection-specialist review, CT or other site-directed imaging, fungal biomarkers where useful and pre-emptive or empirical antifungal treatment under the local pathway.
In transplant or T-cell compromise, timing after transplant and prophylaxis shape risk from CMV, EBV, adenovirus, Pneumocystis, HSV and VZV. Send targeted molecular tests and start syndrome-directed treatment when delay is dangerous.
Discharge is a clinical handover, not simply an afebrile reading. Define antibiotic duration, culture and fungal-result ownership, line plan, neutrophil recovery, prophylaxis restart and exact return thresholds.
Key points
Immunocompromise is not one diagnosis: define whether neutrophils, T cells, B cells or antibody, complement, splenic function or physical barriers are impaired.
Ask for the named condition, current and recent chemotherapy, transplant, biologic and steroid doses, prophylaxis, central access, colonisation, previous organisms and the written emergency plan.
After anticancer treatment, fever above 38°C with neutrophils 0.5 × 10^9/L or lower meets the NICE neutropenic-sepsis definition; clinical sepsis can meet it without documented fever.
Treat suspected neutropenic sepsis as an acute medical emergency and give empirical antibiotics immediately; do not wait for the neutrophil count, C-reactive protein, imaging or culture result.
Initial tests are FBC with differential, renal and liver profile including albumin, CRP, lactate and blood culture; take cultures from each relevant line lumen and a peripheral sample when possible.
For children under 5, perform urinalysis as part of initial assessment. Do not request a routine chest radiograph unless respiratory signs or another clinical indication exists.
NICE first-line empirical treatment is intravenous piperacillin with tazobactam
Aetiology
01
Endogenous flora translocation
Chemotherapy-damaged oral or gastrointestinal mucosa permits Gram-negative, Gram-positive and anaerobic flora to enter blood during neutropenia.
02
Central-line infection
Skin organisms or hub contamination colonise intravascular-catheter biofilm and may cause intermittent bacteraemia, rigors, thrombosis or metastatic infection.
03
Opportunistic or reactivated infection
T-cell suppression and prolonged neutropenia permit invasive fungi, Pneumocystis and latent herpesviruses to cause severe organ-specific or disseminated disease.
04
Community or healthcare exposure
Respiratory viruses, urinary infection, enteric pathogens and resistant healthcare-associated bacteria remain important and can coexist with opportunistic infection.
Pathophysiology
1
Neutrophil defence failure
Reduced phagocyte number and function impairs rapid containment of bacteria and fungi, so a small inoculum can progress without pus.
2
Barrier disruption
Mucositis, wounds and vascular devices breach epithelial protection, creating portals from colonised skin or gut into normally sterile tissue.
3
Cell-mediated immune failure
Impaired T-cell activation weakens control of viruses, fungi and intracellular organisms, allowing latent pathogens to reactivate and disseminate.
4
Humoral or splenic failure
Deficient antibody, complement or splenic clearance reduces opsonisation of encapsulated bacteria and permits sudden high-grade bloodstream infection.
5
Blunted inflammatory signalling
Steroids, cytotoxic treatment and immune dysfunction reduce fever, local inflammation and laboratory responses, making severity appear deceptively mild.
Clinical features and red flags
Define immune defect
Identify neutrophil, T-cell, antibody, complement or splenic impairment and the exact treatment phase before ranking pathogens.
Confirm fever threshold
Measure temperature safely and use the child's emergency plan; absence of fever does not exclude clinically significant sepsis.
Assess physiology early
Record mental state, respiratory effort, oxygen need, heart rate, perfusion, blood pressure, urine output, glucose and lactate.
Inspect portals carefully
Examine mouth, skin, catheter and wounds and ask about respiratory, urinary, abdominal, perianal and neurological symptoms.
Map microbial history
Retrieve previous cultures, resistant colonisation, prophylaxis, recent antibiotics, hospital exposure, travel and household or varicella contact.
Recognise muted inflammation
Do not seek pus or high CRP as prerequisites; profound neutropenia and steroids may remove both findings.
Recognise fungal trajectory
Persistent or recurrent fever with prolonged neutropenia, lung, sinus, skin or neurological findings warrants an invasive-fungal pathway.
Red flags requiring action
Any temperature above the child's oncology threshold, or feeling acutely unwell without fever, requires immediate contact with the designated treatment centre and must not wait for a routine appointment.
Investigations
01First-line: blood cultureFirst stepFirst line
Why
Identify bacteraemia and guide narrowing, resistance management and catheter decisions.
Interpretation and limitations
Culture each relevant central-line lumen and obtain a peripheral culture when possible before antibiotics; do not delay the first dose if access or sampling is difficult.
02First-line: FBC with differentialFirst line
Why
Measure absolute neutrophil count, anaemia and thrombocytopenia and establish treatment safety.
Interpretation and limitations
NICE neutropenic sepsis after anticancer treatment uses neutrophils 0.5 × 10^9/L or lower plus fever above 38°C or clinical sepsis; act before the result when suspected.
03First-line: metabolic and inflammatory panelFirst line
Why
Detect organ dysfunction and establish a trend for response and drug dosing.
Interpretation and limitations
Send renal and liver profile including albumin, CRP and lactate; add glucose, gas, coagulation and other sepsis tests from physiology and local pathway.
04
Differential diagnosis
01
Bacterial bloodstream infection
Endogenous gut organisms, skin flora and catheter pathogens can cause fever alone before shock or a focal source becomes apparent.
02
Viral or fungal infection
Respiratory viruses, HSV, VZV, CMV, adenovirus, Candida and moulds depend on immune defect, prophylaxis, exposure and duration.
03
Neutropenic enterocolitis
Fever with abdominal pain, distension, diarrhoea or bowel-wall thickening during neutropenia represents dangerous inflammatory and microbial bowel injury.
04
Drug or transfusion reaction
Temporal relation to chemotherapy, antimicrobial, blood product or colony-stimulating factor may explain fever but infection must be excluded urgently.
05
Disease-related inflammation
Malignancy progression, haemophagocytic lymphohistiocytosis, graft-versus-host disease and immune reconstitution can mimic infection and require specialist synthesis.
Management
01First hourTreat before test resultsFirst stepA child after anticancer treatment has fever above the agreed threshold or signs consistent with clinically significant sepsis.+
1Activate the oncology or specialist emergency pathway, assess ABCDE and glucose, obtain current weight and involve senior paediatrics and the responsible treatment centre.
2Take central and peripheral cultures where possible plus FBC, renal and liver profile, albumin, CRP and lactate without delaying therapy.
3EscalationGive intravenous piperacillin with tazobactam immediately unless allergy, previous resistance or local microbiology dictates a different empirical regimen, and escalate organ support early.
02DeteriorationEscalate by physiology and historyEscalationShock, organ dysfunction, a new focus or resistant-organism risk appears during initial treatment.
Complications
01
Septic shock
Rapid vasodilation, capillary leak and myocardial dysfunction can cause hypotension, impaired perfusion, lactate rise and death within hours.
02
Multiorgan injury
Hypoxia and inflammatory injury can produce respiratory failure, acute kidney injury, coagulopathy, encephalopathy and hepatic dysfunction.
03
Invasive fungal disease
Prolonged neutropenia permits pulmonary, sinus, cerebral or disseminated mould and yeast infection with high mortality and subtle early signs.
04
Disseminated viral disease
HSV, VZV, CMV or adenovirus can cause pneumonitis, hepatitis, encephalitis, marrow suppression and widespread skin or visceral infection.
05
Treatment disruption
Infection, organ injury and antimicrobial toxicity can delay chemotherapy or transplantation, reduce dose intensity and complicate long-term disease control.
Monitoring and follow-up
Record frequent age-adjusted observations, mental state, capillary refill, blood pressure, oxygen requirement, urine output and lactate until physiology and trajectory are stable.
Review culture status and every previous isolate or resistance result at least daily and sooner when the laboratory reports growth; document narrowing or escalation rationale.
Trend FBC and neutrophil recovery, renal and liver function, electrolytes, CRP and drug-specific toxicity at a frequency matched to illness and treatment.
Inspect the central line, mouth, skin and abdomen repeatedly because a focus may emerge after the first antimicrobial dose and local inflammation may remain minimal.
Complete a validated risk assessment within 24 hours of presentation after anticancer treatment and repeat daily during inpatient management.
For persistent or recurrent fever, track duration and depth of neutropenia, fungal prophylaxis, CT and biomarker results and ownership of tissue or bronchoscopy decisions.
Before discharge, confirm cultures and outstanding-test ownership, antimicrobial stop or step-down criteria, line plan, prophylaxis, specialist follow-up and a written 24-hour return route.
Special situations
Afebrile does not mean uninfected
Steroids and profound immune failure can suppress fever, so altered behaviour or physiology may be the only early signal.
Neutropenia removes pus
A bland throat, line site or radiograph offers less reassurance when the cells that create inflammation are absent.
Cultures guide but never gate
Obtain good central and peripheral samples, but do not let difficult access delay the first empirical antibiotic dose.
A line is risk, not automatic vancomycin
Central access increases bloodstream infection, yet glycopeptide addition still needs a specific clinical or microbiological indication.
Persistent fever is a new assessment
The next step is repeated examination and risk-directed fungal or focal investigation, not reflex substitution of antibiotics.
The immune defect predicts pathogens
Neutrophil, T-cell, antibody, complement and splenic defects create different infection patterns and require different investigations.
Common pitfalls
01
Do not wait for an absolute neutrophil count before treating a child with suspected post-chemotherapy sepsis.
02
Do not require fever when an immunocompromised child has clinically significant deterioration or sepsis signs.
03
Do not delay the first antimicrobial dose while repeatedly attempting a peripheral culture.
04
Do not add an aminoglycoside routinely to initial piperacillin with tazobactam monotherapy.
05
Do not add a glycopeptide or remove the central line solely because the child has central access.
06
Do not order a routine chest radiograph without respiratory or another clinical indication.
07
Do not perform rectal temperature measurement, suppository insertion or digital rectal examination during neutropenia.
08
Do not
monotherapy unless allergy, previous resistance or local microbiology requires another regimen.
Do not routinely add an aminoglycoside, and do not add a glycopeptide solely because a central line is present. Additions require physiology, a suspected focus, colonisation or microbiological evidence.
Do not remove a central venous catheter during initial empirical management unless there is a specific clinical or microbiological indication.
Reassess repeatedly. Persistent fever alone in a stable child is not a reason to change broad-spectrum antibiotics; deterioration or microbiological evidence is.
Use a validated paediatric risk assessment within 24 hours and repeat it daily. Outpatient oral treatment is reserved for specialist-confirmed low risk with robust access and follow-up.
Prolonged neutropenia and persistent or recurrent fever require invasive-fungal assessment and specialist antifungal decisions; ordinary bacterial, viral and noninfectious causes remain possible.
Neutropenia may prevent pus and inflammation, steroids may suppress fever, and antibody deficiency may reduce serological responses; normal-looking findings do not offer ordinary reassurance.
Manage non-neutropenic immunocompromised fever through the immune defect and syndrome: transplant, primary immunodeficiency, asplenia and complement blockade have different likely pathogens and thresholds.
Hypotension, prolonged capillary refill, altered mental state, rising lactate, oliguria, increased oxygen requirement or mottling indicates sepsis with organ dysfunction and needs critical-care escalation.
Rigors during central-line use, tunnel erythema, discharge, line pain or haemodynamic change raises catheter-associated bloodstream infection, but a normal-looking line does not exclude it.
Vesicular rash, eye involvement, hepatitis, pneumonitis, encephalopathy or a significant varicella exposure can represent disseminated herpesvirus infection and needs immediate isolation and specialist antiviral advice.
New focal neurology, severe headache, meningism, seizure or reduced consciousness requires emergency CNS-infection assessment while considering thrombocytopenia and raised intracranial pressure before lumbar puncture.
Persistent fever with prolonged neutropenia, pleuritic pain, hypoxia, sinus symptoms, skin nodules or new lung lesions raises invasive fungal disease.
A child with asplenia, complement inhibition or primary immune deficiency can develop fulminant infection despite normal neutrophils and complete vaccination.
Abdominal pain, distension, diarrhoea, perianal pain or tenderness during neutropenia may indicate enterocolitis or invasive infection and requires urgent imaging and surgical or infection input without rectal examination.
Urine assessment
Why
Identify urinary infection, including in a child without localising symptoms.
Interpretation and limitations
NICE includes urinalysis in children younger than 5; obtain culture when indicated without invasive catheterisation solely for routine screening.
05Site-directed imaging
Why
Investigate respiratory, abdominal, sinus, neurological, line or bone and joint symptoms.
Interpretation and limitations
Do not perform routine chest radiography without a clinical indication. CT, ultrasound or MRI may be needed when ordinary radiographs and inflammatory signs are insensitive.
06Targeted viral and fungal testing
Why
Detect opportunistic infection according to immune defect, illness day and anatomical syndrome.
Interpretation and limitations
Use respiratory PCR, HSV or VZV, CMV or EBV viral load, fungal biomarkers and tissue or bronchoalveolar sampling with specialist advice; negative serum tests do not exclude local disease.
07Lumbar puncture when safe
Why
Diagnose CNS infection when neurological features make it clinically necessary.
Interpretation and limitations
Correct or account for thrombocytopenia, instability, focal signs and raised intracranial-pressure risk; antibiotics and antivirals must not wait for an unsafe procedure.
+
1Repeat ABCDE, lactate and organ assessment, call paediatric critical care and deliver sepsis oxygen, fluid and vasoactive support through the current protocol.
2Use previous isolates, colonisation, allergy, line and focus to broaden or add therapy with microbiology advice rather than applying the same combination to every child.
3Obtain source control and site-directed imaging, including line, abdominal, pulmonary, neurological or surgical review, without postponing stabilisation.
1Repeat the full examination, culture review, immune timeline and medicine history and look for a new line, abdominal, pulmonary, sinus, skin or neurological focus.
2Do not switch antibiotics for fever alone in a clinically stable child; modify when deterioration, microbiology or another clinical finding provides a reason.
3When neutropenia is prolonged, pursue fungal imaging and biomarkers and start pre-emptive or empirical antifungal treatment only through the specialist risk-based pathway.
04Lower-risk recoveryStep down only after specialist reviewThe child is clinically stable and a validated paediatric assessment indicates low risk after initial management.+
1Complete the validated risk assessment within 24 hours and repeat it daily, confirming culture status, focus, neutrophil trajectory and response.
2Use oral or outpatient treatment only when the specialist protocol permits and transport, telephone, adherence, home observation and rapid return are reliable.
3Provide exact return thresholds, named contact, next review and ownership of pending cultures or fungal tests before discharge or antibiotic cessation.
Key medicines and prescribing safety3 treatments · regimens, roles and cautions+
NICE-recommended initial intravenous monotherapy for suspected neutropenic sepsis when patient factors and local microbiology do not contraindicate it.
Piperacillin with tazobactam
For neutropenic fever in children aged 2 to 11 years, give 80 mg piperacillin plus 10 mg tazobactam per kg intravenously every 6 hours, maximum 4 g/0.5 g per dose infused over 30 minutes. From age 12 years give 4 g/0.5 g intravenously every 6 hours. Use the BNFC or specialist neonatal protocol below age 2.
Give immediately after cultures when sampling causes no delay. Check severe beta-lactam allergy, current weight, renal function, sodium burden and previous resistant organisms; adjust in renal impairment and monitor count, electrolytes, kidney and liver function.
Time-critical antiviral treatment for severe or disseminated herpesvirus disease in an immunocompromised child.
Intravenous aciclovir
For specialist-confirmed need in suspected disseminated HSV or VZV, give age 3 months to 11 years 500 mg/m² intravenously every 8 hours, or age 12 to 17 years 10 mg/kg every 8 hours; use the neonatal or renal-adjusted BNFC regimen where applicable.
Do not use routinely for undifferentiated fever. Infuse with adequate hydration, adjust for renal impairment and monitor creatinine and urine output because crystal nephropathy and neurotoxicity can occur; isolate suspected varicella appropriately.
change broad-spectrum antibiotics for persistent fever alone in a stable child without new evidence.
09
Do not discharge on a low-risk label without a validated paediatric pathway, reliable rapid return and named result ownership.
Treats suspected or proven invasive fungal disease during prolonged neutropenia or severe immune dysfunction.
Liposomal amphotericin B
When the specialist invasive-fungal pathway indicates empirical or targeted treatment, a common starting regimen is 3 mg/kg intravenously once daily; use up to 5 mg/kg or an alternative azole or echinocandin according to organism, site, prior prophylaxis and local protocol.
Not required for every persistent fever. Obtain fungal, imaging and microbiology input, check interactions and monitor renal function, potassium, magnesium, liver tests, blood count and infusion reactions.