My child has chickenpox — do they need antiviral medication?

In otherwise healthy children, chickenpox (varicella) is a self-limiting illness managed with paracetamol for fever and discomfort, and calamine lotion or antihistamines for itch. Antiviral medication (aciclovir) is not routinely recommended for healthy children because the illness resolves without it and antibiotic stewardship principles apply equally to antivirals. Aciclovir is indicated for children or adults who are immunocompromised, pregnant women with varicella, neonates exposed at delivery, adults with primary varicella (who experience more severe disease), or anyone with complications such as pneumonia or encephalitis.

What is Kawasaki disease and why does it require urgent treatment?

Kawasaki disease is an immune-mediated inflammatory illness of unknown cause affecting medium-sized blood vessels, predominantly in children under 5 years. It causes fever lasting 5 or more days alongside characteristic features: bilateral non-purulent conjunctivitis, a polymorphous rash, red and cracked lips or strawberry tongue, swelling and redness of the hands and feet, and cervical lymphadenopathy. Without treatment, approximately 25% of children develop coronary artery aneurysms, which can lead to heart attack. IVIG 2 g/kg given within 10 days of fever onset reduces this risk to under 5%. This is why any child with fever lasting 5 or more days warrants urgent consideration of Kawasaki disease.

My child got a rash after taking amoxicillin during a glandular fever infection — is this a penicillin allergy?

No. A maculopapular (flat, widespread) rash appearing during Epstein-Barr virus (glandular fever, EBV) infection after amoxicillin or ampicillin is called Hoagland's sign — it occurs in up to 90% of EBV patients given aminopenicillins. This is not an IgE-mediated allergic reaction and is not a true penicillin allergy. It is crucial not to document this as a penicillin allergy in the child's records, because incorrectly labelling a child with penicillin allergy restricts access to first-line antibiotics for years and increases risk from second-line alternatives.

When is a rash with fever an emergency requiring immediate hospital care?

Seek emergency care immediately if: the rash is petechial (small, flat, dark red or purple spots that do not fade when pressed) or purpuric (larger bruise-like patches) — this pattern with fever suggests meningococcaemia and antibiotics must be given before any other investigation; the rash involves the mucous membranes (mouth, eyes, genitals) with skin blistering or peeling, suggesting Stevens-Johnson syndrome or toxic epidermal necrolysis; the child has a known atopic eczema and develops vesicles with fever suggesting eczema herpeticum; or the child looks toxic, is struggling to breathe, has drooling or difficulty swallowing, or is unusually drowsy or difficult to rouse.

Which childhood rashes require notification to public health authorities?

In Australia, measles is the most urgent — notify the same day by phone to the state public health unit; airborne isolation is required. Other nationally or state-notifiable conditions include rubella, mumps, invasive meningococcal disease (which can present with a rash), invasive group A streptococcal disease (including severe scarlet fever complications), pertussis, and varicella (notifiable in some states). HFMD, roseola, and parvovirus B19 are not notifiable. Your GP will notify on your behalf when a notifiable condition is suspected. The CDNA Series of National Guidelines provides disease-specific notification criteria.

Childhood viral exanthems and hand-foot-mouth disease

Childhood viral exanthems: recognition, treatment, and not-to-miss mimics

By Dr HB Lo, FACRRM Reviewed 18 July 2026 11 min read

Most childhood viral rashes — parvovirus B19 (slapped cheek), roseola, varicella, and HFMD — are self-limiting and managed supportively. Scarlet fever (group A streptococcus) is the exception: 10 days of phenoxymethylpenicillin is required to prevent acute rheumatic fever.

Critical not-to-miss mimics: Kawasaki disease (fever ≥5 days — IVIG within 10 days; untreated coronary aneurysm risk ~25%), meningococcaemia (petechial or purpuric rash with fever — immediate antibiotics), and Stevens-Johnson syndrome (mucosal blistering — emergency admission).

NIP vaccination prevents measles, rubella, and varicella. Pregnant contacts require urgent serology and specialist obstetric review.

Childhood rashes are among the most common presentations in Australian general practice, particularly during the winter and spring seasons. Most are self-limiting viral exanthems requiring only supportive care and parental reassurance. However, several conditions that can initially appear to be a routine rash represent genuine emergencies — and recognising them promptly can prevent catastrophic outcomes.

The key clinical skill is not memorising every rash pattern, but reliably identifying the critical not-to-miss conditions at every assessment: meningococcaemia, Kawasaki disease, Stevens-Johnson syndrome (SJS), and eczema herpeticum. All four require immediate action and are identifiable on clinical assessment.

This article covers the common viral exanthems encountered in Australian general practice, the bacterial cause (scarlet fever) requiring antibiotic treatment, the critical mimics, vaccination context, and mandatory notification requirements.

A. Core clinical — the AU general-practice framework

Measles (rubeola)

Measles is highly contagious (airborne; ~90% attack rate in non-immune contacts) and remains a risk through imported cases despite Australian elimination in 2014. The prodrome runs 2–4 days with cough, coryza, conjunctivitis (the “3 Cs”), and high fever. Koplik spots — small white spots on the buccal mucosa appearing 1–2 days before the rash — are pathognomonic when seen. The rash is maculopapular, beginning at the hairline and spreading head-to-foot, becoming confluent over 5–7 days.

Complications include otitis media (~10%), pneumonia (~5%), and encephalitis (~1 in 1,000). Measles is notifiable same-day to the state public health unit; airborne isolation is required. Vitamin A is recommended for confirmed measles (WHO recommendation) — reduce morbidity and complications.

Rubella (German measles)

Rubella causes a mild pinkish maculopapular rash beginning on the face, spreading to trunk and extremities over 3 days, with characteristic posterior auricular and suboccipital lymphadenopathy. Adult women frequently experience arthralgia. The clinical illness is mild, but rubella is a devastating teratogen — congenital rubella syndrome (cataracts, sensorineural deafness, cardiac defects) occurs with first-trimester exposure. Rubella is notifiable. Pregnancy contact tracing is the clinical priority. Incidence is greatly reduced post-MMR vaccination.

Parvovirus B19 (erythema infectiosum, “slapped cheek”, fifth disease)

The characteristic presentation is a “slapped cheek” facial rash (bright erythema of both cheeks with circumoral pallor), followed 1–4 days later by a lacy or reticulated rash on the extremities that waxes and wanes with heat and sun exposure over weeks. The child is often unwell with mild fever before the rash and well-looking once the rash appears.

Critical considerations:

Aplastic crisis in patients with chronic haemolytic anaemia (sickle cell disease, hereditary spherocytosis, thalassaemia) — present with severe anaemia; admission and transfusion
Pregnancy — fetal hydrops and intrauterine death, especially before 20 weeks; urgent serology and specialist fetal medicine referral

Adult joint involvement (symmetric polyarthritis) is a common but often unrecognised presentation.

Roseola (exanthem subitum, sixth disease — HHV-6)

Roseola affects infants and toddlers 6–24 months. High fever for 3–5 days in an otherwise surprisingly well-looking child, followed by defervescence and emergence of a pink maculopapular rash on the trunk and neck. The rash appears as the fever breaks and lasts 1–2 days. A febrile convulsion during the high fever phase is common. Management is supportive; the key diagnostic clue is the characteristic sequence of high fever → sudden defervescence → rash.

Varicella (chickenpox)

Varicella (primary VZV infection) produces a vesicular rash in crops, with lesions simultaneously in different stages (papule, vesicle, pustule, crust) across the scalp, face, trunk, and extremities. The rash is intensely pruritic. The child is contagious from 1–2 days before the rash appears until all lesions have crusted (approximately 5–7 days).

Per eTG and AMH: aciclovir is not routinely recommended for otherwise healthy children. It is indicated for immunocompromised patients, adults with primary varicella (more severe), pregnant women with varicella, neonates with maternal exposure at delivery, and anyone with complications (pneumonia, encephalitis). Avoid aspirin in varicella — Reye syndrome risk. Incidence has fallen markedly since introduction of varicella vaccine on the NIP.

Varicella reactivation as herpes zoster is addressed in the herpes-simplex-zoster article.

Scarlet fever (group A streptococcus)

Scarlet fever is a bacterial exanthem requiring antibiotic treatment. The rash is a fine punctate erythema (“sandpaper texture”) beginning on the trunk and spreading outwards, with circumoral pallor and strawberry tongue (enlarged red papillae). It accompanies or follows group A streptococcal pharyngitis (sore throat, exudative tonsillitis, tender cervical nodes). Palmar and plantar desquamation occurs 1–2 weeks after the rash.

Treatment is essential to prevent acute rheumatic fever and post-streptococcal glomerulonephritis: phenoxymethylpenicillin (weight-based) for 10 days — a shorter course is inadequate for rheumatic fever prevention. Alternative: amoxicillin or cefalexin for penicillin allergy. Global re-emergence of scarlet fever has been noted since approximately 2014.

Hand-foot-mouth disease (HFMD)

HFMD is caused by coxsackie virus A6, A16, or enterovirus 71. The characteristic presentation is vesicles or erosions on the palms, soles, and oral mucosa (painful ulcers), often with a macular rash on the buttocks and mild fever. Childcare outbreaks are common in the warm season.

Management is supportive only — analgesia (paracetamol), oral fluids, soft or cold foods for oral ulcers. RCH guidelines recommend school and childcare exclusion until lesions are dry. Transient nail loss (onychomadesis) occurring 1–2 months later is a recognised but harmless post-infectious phenomenon. Severe HFMD with neurological features (encephalitis, brainstem involvement) is associated with enterovirus 71 and is uncommon in Australia but significant in South-East Asia.

B. Critical mimics — never miss these

Kawasaki disease

Kawasaki disease is a medium-vessel vasculitis of unknown aetiology, predominantly affecting children under 5 years. Coronary artery aneurysms develop in approximately 25% of untreated children, making early recognition essential.

Classic diagnostic criteria: fever ≥5 days plus ≥4 of:

Bilateral non-purulent conjunctivitis
Polymorphous rash (not vesicular)
Mucosal changes — red or cracked lips, strawberry tongue, oropharyngeal erythema
Extremity changes — palmar/plantar erythema or oedema; later periungual desquamation
Cervical lymphadenopathy ≥1.5 cm (often unilateral)

“Incomplete Kawasaki” occurs when fewer than 4 criteria are met — maintain suspicion in any child with unexplained fever ≥5 days.

Treatment: Admit immediately. IVIG 2 g/kg as a single infusion within 10 days of fever onset reduces coronary aneurysm incidence to under 5%. Aspirin is given concurrently (anti-inflammatory dose, then antiplatelet). Echocardiogram at baseline and 6–8 weeks. Cardiology follow-up for coronary abnormalities.

Meningococcaemia

A petechial or purpuric rash with fever in a child is meningococcaemia until proven otherwise. The rash begins as petechiae (pinhead-sized non-blanching spots) and rapidly expands to large purpuric lesions. The child may progress to septic shock, DIC, and Waterhouse-Friderichsen syndrome within hours.

Do not wait to investigate — administer antibiotics first: IV or IM ceftriaxone (or benzylpenicillin) immediately, then transfer to emergency department. Notification to the public health unit triggers contact prophylaxis (rifampicin or ciprofloxacin for close contacts).

Stevens-Johnson syndrome (SJS) / toxic epidermal necrolysis (TEN)

SJS and TEN are severe, potentially life-threatening drug hypersensitivity reactions causing mucosal involvement (oral, ocular, urogenital) alongside extensive skin blistering and detachment. SJS involves <10% body surface area; TEN ≥30%; overlap 10–30%. High-risk drugs include aromatic anticonvulsants (carbamazepine — especially in patients of Han Chinese or South-East Asian ancestry carrying HLA-B*1502 allele), lamotrigine, allopurinol, sulfonamides, NSAIDs, and some antibiotics.

If SJS/TEN is suspected: cease the offending drug immediately, transfer to emergency department, and arrange burns-unit or dermatology consultation. Mortality from TEN ranges from 10–40%.

Eczema herpeticum

In a child with atopic dermatitis who develops vesicles, erosions, fever, and looks unwell, suspect eczema herpeticum — HSV infection spreading across eczematous skin. This can be widespread and severe, including ophthalmic involvement. Emergency treatment with aciclovir (IV for severe; oral for milder cases) is required. See the atopic-dermatitis article for details.

C. Vaccination, treatment, and notification

Vaccination — National Immunisation Program

The NIP schedule protects against measles, mumps, rubella, and varicella:

MMR (12 months) + MMRV (18 months) — combined measles-mumps-rubella-varicella
Varicella: incorporated in MMRV at 18 months; or separate varicella vaccine if not already immune
HPV: 12–13 years (school-based, single dose since 2023)
Meningococcal ACWY: 12 months + 14–16 years (NIP); MenB for high-risk groups
dTpa: 14–16 years adolescent boost + maternal dTpa in pregnancy

Check vaccination status at every paediatric acute encounter — especially measles and varicella, where catch-up is critical.

Post-exposure prophylaxis:

MMR within 72 hours for non-immune measles contacts — effective if given promptly
Varicella zoster immunoglobulin (VZIG) within 10 days for high-risk varicella contacts (non-immune pregnant women, immunocompromised, neonates) — Authority Required; coordinate via specialist and Lifeblood

Treatment summary

Condition	Treatment
Measles	Supportive; vitamin A for confirmed cases; notify same day
Rubella	Supportive; notify; urgent obstetric review if pregnant contact
Parvovirus B19	Supportive (immunocompetent); transfusion for aplastic crisis; obstetric review if pregnant contact
Roseola	Supportive
Varicella (healthy child)	Supportive; paracetamol; calamine; avoid aspirin
Varicella (severe/complicated)	Aciclovir; dose per AMH weight-based guidance
Scarlet fever	Phenoxymethylpenicillin 10 days (weight-based)
HFMD	Supportive; analgesia; childcare exclusion until dry
Kawasaki	IVIG 2 g/kg + aspirin; admit; echo
Meningococcaemia	Ceftriaxone immediately + 000
SJS/TEN	Cease drug; emergency transfer
Eczema herpeticum	Aciclovir; emergency management

D. Australian operations

MBS items (verify before billing)

Standard consultations: items 3 / 23 / 36 / 44
ATSI Health Assessment: item 715; Healthy Kids Check: item 709
Practice nurse vaccination: item 10987
GPCCMP: items 965 / 967 — for chronic sequelae (post-Kawasaki coronary disease, recurrent infections)
Mental Health Care Plan: items 2715 / 2717 — carer stress and burnout from repeated paediatric illness is common and deserves its own conversation

Mandatory notification requirements

Same-day phone notification to the state public health unit is required for:

Measles — highest priority; airborne isolation; contact tracing
Rubella, mumps
Invasive meningococcal disease (all serogroups)
Invasive group A streptococcal disease (complicated scarlet fever, necrotising fasciitis)
Pertussis, polio, COVID-19, influenza A (novel strains)
Varicella — notifiable in some states (check local requirements)

The GP notifies; reporting forms and procedures are available through the Department of Health and the CDNA SoNG for each disease.

Pregnancy contacts

Advise urgent obstetric review and same-day serology for any pregnant woman exposed to:

Measles — MMR PEP within 72 hours if non-immune
Rubella — serology; if non-immune, post-exposure immunoglobulin (specialist input)
Parvovirus B19 — serial USS for fetal hydrops if maternal infection confirmed, especially before 20 weeks
Varicella — VZIG within 10 days if non-immune

School and childcare exclusion

Per NHMRC Staying Healthy guidelines:

Condition	Exclusion period
Measles	Until 4 days after rash onset
Rubella	Until 4 days after rash onset
Varicella	Until all lesions have crusted
Scarlet fever	Until 24 hours of antibiotic + clinically well
HFMD	Until lesions are dry
Roseola, parvovirus B19	No exclusion once well enough to attend

E. Special populations

Immunocompromised children. Varicella can be life-threatening in children on chemotherapy, post-haematopoietic stem cell transplant, or with primary immunodeficiency. Measles can cause fatal giant-cell pneumonitis. Any rash in an immunocompromised child warrants urgent specialist review. Aciclovir for varicella; ceftriaxone + urgent admission for suspected meningococcaemia; VZIG for varicella exposure. The Australian Immunisation Handbook provides vaccination guidance for immunocompromised children.

Infants under 12 months. Not yet fully vaccinated for measles and varicella. Any febrile rash warrants careful assessment. Maternal MMR and varicella vaccine history and serological status inform exposure risk. Neonatal varicella (maternal infection 5 days before to 2 days after delivery) is severe — VZIG urgently.

Aboriginal and Torres Strait Islander children. Higher risk of serious infectious disease complications; ensure NIP is current at every opportunity. Rheumatic fever risk from group A streptococcal infections (including scarlet fever) is substantially higher in ATSI communities, particularly in remote and regional areas — 10-day antibiotic course completion is critical.

Carer mental health. Repeated childcare-aged illness — particularly during overlapping viral seasons — places significant stress on working parents and caregivers. Validate this burden during the consultation; the GP encounter is an opportunity to also check in on carer wellbeing.

When to escalate

Call 000 or transfer to ED immediately:

Petechial or purpuric rash with fever — meningococcaemia; give ceftriaxone before transport if available
Suspected SJS/TEN — mucosal involvement + skin blistering; cease drug; emergency transfer
Eczema herpeticum — widespread vesicles on eczematous skin with fever; urgent IV aciclovir
Suspected epiglottitis — drooling, stridor, tripod posture; do not examine throat; call 000
Any child with rash who is in septic shock, unconscious, or in severe respiratory distress

Same-day or next-day urgent review:

Suspected Kawasaki disease — fever ≥5 days with any supporting features; admit for IVIG
Pregnant woman exposed to measles, rubella, parvovirus B19, or varicella — serology and obstetric review
Aplastic crisis in haemolytic anaemia patient with parvovirus B19 — FBC urgently

Routine specialist referral:

Confirmed post-Kawasaki coronary abnormalities — paediatric cardiology
Persistent or recurrent group A strep infection in ATSI child in high-rheumatic-fever-risk area — CARPA guidelines

What this article is and is not

This is general health information drawn from current Australian guidelines — RCH Melbourne Clinical Practice Guidelines, the Australian Immunisation Handbook, Therapeutic Guidelines (eTG), the Australian Medicines Handbook, NHMRC Staying Healthy guidelines, and the Department of Health notifiable disease framework. It is not personal medical advice and does not replace assessment by your child’s GP or treating clinician.

For Australian consumer resources: HealthDirect — Childhood rashes, RCH Kids Health Information, Better Health Channel — Chickenpox.

For acute emergency: call 000 if your child has a petechial rash with fever, is struggling to breathe, is unusually difficult to rouse, or you are concerned about their immediate safety.

Sources cited

Frequently asked questions

My child has chickenpox — do they need antiviral medication?

In otherwise healthy children, chickenpox (varicella) is a self-limiting illness managed with paracetamol for fever and discomfort, and calamine lotion or antihistamines for itch. Antiviral medication (aciclovir) is not routinely recommended for healthy children because the illness resolves without it and antibiotic stewardship principles apply equally to antivirals. Aciclovir is indicated for children or adults who are immunocompromised, pregnant women with varicella, neonates exposed at delivery, adults with primary varicella (who experience more severe disease), or anyone with complications such as pneumonia or encephalitis.
What is Kawasaki disease and why does it require urgent treatment?

Kawasaki disease is an immune-mediated inflammatory illness of unknown cause affecting medium-sized blood vessels, predominantly in children under 5 years. It causes fever lasting 5 or more days alongside characteristic features: bilateral non-purulent conjunctivitis, a polymorphous rash, red and cracked lips or strawberry tongue, swelling and redness of the hands and feet, and cervical lymphadenopathy. Without treatment, approximately 25% of children develop coronary artery aneurysms, which can lead to heart attack. IVIG 2 g/kg given within 10 days of fever onset reduces this risk to under 5%. This is why any child with fever lasting 5 or more days warrants urgent consideration of Kawasaki disease.
My child got a rash after taking amoxicillin during a glandular fever infection — is this a penicillin allergy?

No. A maculopapular (flat, widespread) rash appearing during Epstein-Barr virus (glandular fever, EBV) infection after amoxicillin or ampicillin is called Hoagland's sign — it occurs in up to 90% of EBV patients given aminopenicillins. This is not an IgE-mediated allergic reaction and is not a true penicillin allergy. It is crucial not to document this as a penicillin allergy in the child's records, because incorrectly labelling a child with penicillin allergy restricts access to first-line antibiotics for years and increases risk from second-line alternatives.
When is a rash with fever an emergency requiring immediate hospital care?

Seek emergency care immediately if: the rash is petechial (small, flat, dark red or purple spots that do not fade when pressed) or purpuric (larger bruise-like patches) — this pattern with fever suggests meningococcaemia and antibiotics must be given before any other investigation; the rash involves the mucous membranes (mouth, eyes, genitals) with skin blistering or peeling, suggesting Stevens-Johnson syndrome or toxic epidermal necrolysis; the child has a known atopic eczema and develops vesicles with fever suggesting eczema herpeticum; or the child looks toxic, is struggling to breathe, has drooling or difficulty swallowing, or is unusually drowsy or difficult to rouse.
Which childhood rashes require notification to public health authorities?

In Australia, measles is the most urgent — notify the same day by phone to the state public health unit; airborne isolation is required. Other nationally or state-notifiable conditions include rubella, mumps, invasive meningococcal disease (which can present with a rash), invasive group A streptococcal disease (including severe scarlet fever complications), pertussis, and varicella (notifiable in some states). HFMD, roseola, and parvovirus B19 are not notifiable. Your GP will notify on your behalf when a notifiable condition is suspected. The CDNA Series of National Guidelines provides disease-specific notification criteria.

Source quality

Sources grouped by evidence tier. AU primary tier first; international where AU is silent or lagging; named-author reconstruction where guidelines have not yet caught up. How tiers work.

T1 AU primary 12 sources