FCPS Paediatrics TOACS · Interactive Station
🩺 Neonatal Rash — Erythema Toxicum Neonatorum (ETN) · Recognition, Differential Diagnosis & Parental Counseling
📚 Paeds Online – paeds.online
⚕️ OBSERVED STATION · CPSP FORMAT · 6-8 MINUTES · NEONATAL DERMATOLOGY
📖 Problem-Oriented Clinical Scenario + Image (Neonatal Rash)
👶🏻 Clinical Scenario (read aloud – 2 minutes):
A 2-day-old term neonate born at 39 weeks by normal spontaneous vaginal delivery is brought to the newborn nursery for routine evaluation. The baby was discharged home at 24 hours of age after an uneventful course. The mother reports that today she noticed multiple “red bumps with white centres” on the infant’s trunk and proximal extremities. The infant is exclusively breastfed, feeds well (every 2–3 hours), is alert, and has normal urine and stool output. There is no fever, no irritability, and no respiratory distress.
On examination, vital signs are normal (temperature 36.8°C, HR 140/min, RR 40/min, SpO2 98% on room air). You observe multiple 1–3 mm erythematous macules and papules with central vesicles/pustules (“flea-bitten” appearance) scattered over the chest, back, and proximal arms. The palms, soles, and mucous membranes are clear. The rash is non-confluent and individual lesions appear at different stages. The infant is otherwise thriving and well-appearing.
Image: A representative clinical photograph of the rash is shown below (Erythema toxicum neonatorum).
Task: Describe the rash, propose the most likely diagnosis, discuss differential diagnoses, answer examiner questions regarding benign neonatal rashes, and counsel the parents.
A 2-day-old term neonate born at 39 weeks by normal spontaneous vaginal delivery is brought to the newborn nursery for routine evaluation. The baby was discharged home at 24 hours of age after an uneventful course. The mother reports that today she noticed multiple “red bumps with white centres” on the infant’s trunk and proximal extremities. The infant is exclusively breastfed, feeds well (every 2–3 hours), is alert, and has normal urine and stool output. There is no fever, no irritability, and no respiratory distress.
On examination, vital signs are normal (temperature 36.8°C, HR 140/min, RR 40/min, SpO2 98% on room air). You observe multiple 1–3 mm erythematous macules and papules with central vesicles/pustules (“flea-bitten” appearance) scattered over the chest, back, and proximal arms. The palms, soles, and mucous membranes are clear. The rash is non-confluent and individual lesions appear at different stages. The infant is otherwise thriving and well-appearing.
Image: A representative clinical photograph of the rash is shown below (Erythema toxicum neonatorum).
Task: Describe the rash, propose the most likely diagnosis, discuss differential diagnoses, answer examiner questions regarding benign neonatal rashes, and counsel the parents.
🔍 Figure: Erythema toxicum neonatorum (ETN). Note the scattered erythematous macules with central papules/pustules (classic “flea-bitten” appearance) on the trunk. The infant is otherwise well, no systemic symptoms. This is the most common benign pustular rash in newborns.
💡 Examiner instruction (interactive): The candidate will describe the image, identify the condition, differentiate from other neonatal pustular/vesicular rashes (HSV, candidiasis, miliaria, transient neonatal pustular melanosis, etc.), discuss pathophysiology, and provide appropriate parental counseling.
🔍 Examiner Q&A – Neonatal Rash (ETN)
❓ Q1 (Examiner): “Describe the findings in the image and give the most likely diagnosis.”
✅ Candidate’s structured answer:
• Findings: Multiple 1–3 mm erythematous macules and papules with central vesicles/pustules (pustule on an erythematous base) distributed mainly on trunk and proximal extremities. Palms, soles, mucosa spared. Lesions at different stages of evolution.
• Diagnosis: Erythema toxicum neonatorum (ETN) – also called “erythema neonatorum toxicum.”
• Key point: Benign, self-limited, idiopathic rash of term newborns, typically appears within first few days of life.
• Findings: Multiple 1–3 mm erythematous macules and papules with central vesicles/pustules (pustule on an erythematous base) distributed mainly on trunk and proximal extremities. Palms, soles, mucosa spared. Lesions at different stages of evolution.
• Diagnosis: Erythema toxicum neonatorum (ETN) – also called “erythema neonatorum toxicum.”
• Key point: Benign, self-limited, idiopathic rash of term newborns, typically appears within first few days of life.
❓ Q2 (Examiner): “What is the typical age of onset and incidence of Erythema toxicum neonatorum?”
✅ Candidate's answer:
• Onset: usually between 24 and 72 hours of life; can be present at birth but rare.
• Incidence: affects approximately 30–70% of full-term newborns; less common in preterm infants.
• No gender or racial predilection; more common in infants with higher birth weight.
• Onset: usually between 24 and 72 hours of life; can be present at birth but rare.
• Incidence: affects approximately 30–70% of full-term newborns; less common in preterm infants.
• No gender or racial predilection; more common in infants with higher birth weight.
❓ Q3 (Examiner): “What are the important differential diagnoses for a pustular/vesicular rash in a neonate?”
✅ Candidate's answer:
• Benign: Transient neonatal pustular melanosis (TNPM; more common in Black infants, pustules rupture leaving hyperpigmented macules), Miliaria (crystallina/rubra; due to heat/occlusion), Acropustulosis of infancy (recurrent, pruritic).
• Infectious (must rule out): Neonatal herpes simplex (vesicles, grouped, often on scalp/face, maternal history, sick infant), Congenital candidiasis (widespread, erythematous papules/pustules, can be present at birth or after), Staphylococcal pustulosis (periumbilical, perineal, often with systemic signs), Scabies (intense itching, family involvement).
• Key distinguishing feature of ETN: Well-appearing infant, eosinophilic pustules on smear, spontaneous resolution.
• Benign: Transient neonatal pustular melanosis (TNPM; more common in Black infants, pustules rupture leaving hyperpigmented macules), Miliaria (crystallina/rubra; due to heat/occlusion), Acropustulosis of infancy (recurrent, pruritic).
• Infectious (must rule out): Neonatal herpes simplex (vesicles, grouped, often on scalp/face, maternal history, sick infant), Congenital candidiasis (widespread, erythematous papules/pustules, can be present at birth or after), Staphylococcal pustulosis (periumbilical, perineal, often with systemic signs), Scabies (intense itching, family involvement).
• Key distinguishing feature of ETN: Well-appearing infant, eosinophilic pustules on smear, spontaneous resolution.
❓ Q4 (Examiner): “What is the proposed etiology/pathophysiology of Erythema toxicum neonatorum?”
✅ Candidate's answer:
• Exact cause unknown; considered a benign inflammatory reaction of the newborn skin.
• Theories: reaction to hair follicle/sweat gland colonization? immune response to meconium or vernix?
• Histology: intrafollicular subcorneal pustules containing numerous eosinophils; dermal perivascular eosinophilic infiltration.
• No evidence of infection; cultures are sterile.
• Exact cause unknown; considered a benign inflammatory reaction of the newborn skin.
• Theories: reaction to hair follicle/sweat gland colonization? immune response to meconium or vernix?
• Histology: intrafollicular subcorneal pustules containing numerous eosinophils; dermal perivascular eosinophilic infiltration.
• No evidence of infection; cultures are sterile.
❓ Q5 (Examiner): “Do you need any laboratory tests or workup for this infant? If yes, what?”
✅ Candidate's answer:
• In a well-appearing, afebrile term infant with typical ETN, no investigations are necessary.
• If diagnosis uncertain (e.g., sick infant, maternal history of HSV), obtain: Tzanck smear (multinucleated giant cells in HSV), Gram stain/culture of pustule (sterile in ETN, may show eosinophils – Giemsa or Wright stain shows eosinophils), and HSV PCR if vesicles present.
• Key point: ETN is a clinical diagnosis; over-investigation is discouraged.
• In a well-appearing, afebrile term infant with typical ETN, no investigations are necessary.
• If diagnosis uncertain (e.g., sick infant, maternal history of HSV), obtain: Tzanck smear (multinucleated giant cells in HSV), Gram stain/culture of pustule (sterile in ETN, may show eosinophils – Giemsa or Wright stain shows eosinophils), and HSV PCR if vesicles present.
• Key point: ETN is a clinical diagnosis; over-investigation is discouraged.
❓ Q6 (Examiner): “What is the natural history and prognosis of ETN?”
✅ Candidate's answer:
• Self-limited: lesions typically resolve spontaneously within 5–14 days without scarring.
• No treatment required; no recurrence after resolution.
• No systemic involvement; no association with later atopy or other diseases.
• Excellent prognosis; reassurance is the mainstay.
• Self-limited: lesions typically resolve spontaneously within 5–14 days without scarring.
• No treatment required; no recurrence after resolution.
• No systemic involvement; no association with later atopy or other diseases.
• Excellent prognosis; reassurance is the mainstay.
❓ Q7 (Examiner): “How will you counsel the parents of this infant?”
✅ Candidate's answer:
• “Your baby has a very common, harmless rash called Erythema toxicum neonatorum. It is not an infection, not contagious, and does not cause pain or itching.”
• Explain that it usually appears in the first few days, lasts about 1–2 weeks, then disappears on its own without any treatment.
• No creams, ointments, or discontinuation of breastfeeding needed; normal bathing and care.
• Advise warning signs that should prompt re-evaluation: fever, lethargy, poor feeding, progression to vesicles on palms/soles/mucosa, or if the infant appears ill.
• Reassure that this does NOT increase risk of allergies or future skin problems.
• “Your baby has a very common, harmless rash called Erythema toxicum neonatorum. It is not an infection, not contagious, and does not cause pain or itching.”
• Explain that it usually appears in the first few days, lasts about 1–2 weeks, then disappears on its own without any treatment.
• No creams, ointments, or discontinuation of breastfeeding needed; normal bathing and care.
• Advise warning signs that should prompt re-evaluation: fever, lethargy, poor feeding, progression to vesicles on palms/soles/mucosa, or if the infant appears ill.
• Reassure that this does NOT increase risk of allergies or future skin problems.
❓ Q8 (Examiner): “How do you differentiate ETN from transient neonatal pustular melanosis (TNPM)?”
✅ Candidate's answer:
• TNPM: pustules without erythema, present at birth or first 24h; pustules rupture easily leaving collarette of scale and hyperpigmented macules (“freckle-like”).
• More common in Black/African American infants.
• Smear: neutrophils (not eosinophils).
• ETN: erythematous base, appears later (24–72h), no residual hyperpigmentation; smear shows eosinophils.
• TNPM: pustules without erythema, present at birth or first 24h; pustules rupture easily leaving collarette of scale and hyperpigmented macules (“freckle-like”).
• More common in Black/African American infants.
• Smear: neutrophils (not eosinophils).
• ETN: erythematous base, appears later (24–72h), no residual hyperpigmentation; smear shows eosinophils.
❓ Q9 (Examiner): “A baby in nursery develops tiny clear vesicles on forehead and neck after being swaddled excessively. What is that, and how does it differ from ETN?”
✅ Candidate's answer:
• Miliaria crystallina (sudamina) – due to sweat duct occlusion. Clear, fragile vesicles without erythema; often in intertriginous areas, face, neck.
• ETN: erythematous papules with central pustule, on trunk, no relation to overheating.
• Miliaria rubra (prickly heat): erythematous papules/pustules, pruritic, occurs with heat/humidity; resolves with cooling.
• Miliaria crystallina (sudamina) – due to sweat duct occlusion. Clear, fragile vesicles without erythema; often in intertriginous areas, face, neck.
• ETN: erythematous papules with central pustule, on trunk, no relation to overheating.
• Miliaria rubra (prickly heat): erythematous papules/pustules, pruritic, occurs with heat/humidity; resolves with cooling.
❓ Q10 (Examiner): “What are the ‘red flags’ that should raise suspicion for serious infection in a neonate with a rash?”
✅ Candidate's answer:
• Ill-appearance: lethargy, poor feeding, temperature instability (hypo/hyperthermia), apnea, irritability.
• Maternal history: fever, HSV, rash, or positive serologies (syphilis, varicella).
• Rash characteristics: vesicles on palms/soles or mucous membranes (HSV), purpura/echymosis (congenital infection), pustules with surrounding cellulitis (bacterial).
• Rapid progression or systemic signs require immediate evaluation (CBC, CRP, blood culture, HSV PCR, CSF analysis as indicated).
• Ill-appearance: lethargy, poor feeding, temperature instability (hypo/hyperthermia), apnea, irritability.
• Maternal history: fever, HSV, rash, or positive serologies (syphilis, varicella).
• Rash characteristics: vesicles on palms/soles or mucous membranes (HSV), purpura/echymosis (congenital infection), pustules with surrounding cellulitis (bacterial).
• Rapid progression or systemic signs require immediate evaluation (CBC, CRP, blood culture, HSV PCR, CSF analysis as indicated).
❓ Q11 (Examiner): “Is ETN seen in premature infants? If not, what rash is more common in preterm?”
✅ Candidate's answer:
• ETN is less common in preterm infants, possibly due to immature pilosebaceous units.
• Preterm infants more often have: Miliaria (due to immature sweat ducts), Cutis marmorata (physiologic vasomotor), Benign neonatal pustulosis, or Candida if prolonged NICU stay. However, ETN can still occur in late preterm.
• ETN is less common in preterm infants, possibly due to immature pilosebaceous units.
• Preterm infants more often have: Miliaria (due to immature sweat ducts), Cutis marmorata (physiologic vasomotor), Benign neonatal pustulosis, or Candida if prolonged NICU stay. However, ETN can still occur in late preterm.
❓ Q12 (Examiner): “What specific treatment do you recommend for ETN?”
✅ Candidate's answer:
• No treatment required. Avoid topical steroids, antibiotics, or antifungals.
• Continue routine skin care: gentle cleansing with water, pat dry, no oily ointments.
• Parental reassurance and education on warning signs.
• Routine follow-up with pediatrician; the rash will clear without scarring.
• No treatment required. Avoid topical steroids, antibiotics, or antifungals.
• Continue routine skin care: gentle cleansing with water, pat dry, no oily ointments.
• Parental reassurance and education on warning signs.
• Routine follow-up with pediatrician; the rash will clear without scarring.
🗣️ Examiner’s high-yield probing points:
• “What would you tell a mother who is very anxious and wants antibiotics?” → Reassure that ETN is not an infection, and antibiotics are unnecessary and potentially harmful.
• “When do you refer to dermatology?” → Rarely needed; refer only if rash persists >3 weeks, vesicles evolve to ulcers, or systemic signs appear.
• “What stain is used to confirm eosinophils?” → Wright’s or Giemsa stain of pustule content.
• “What would you tell a mother who is very anxious and wants antibiotics?” → Reassure that ETN is not an infection, and antibiotics are unnecessary and potentially harmful.
• “When do you refer to dermatology?” → Rarely needed; refer only if rash persists >3 weeks, vesicles evolve to ulcers, or systemic signs appear.
• “What stain is used to confirm eosinophils?” → Wright’s or Giemsa stain of pustule content.
📘 Topic Summary: Erythema Toxicum Neonatorum (ETN)
🔍 Definition
Benign, self-limited, idiopathic erythematous maculopapular rash with central pustules; occurs in 30–70% of term newborns within first 72 hours.
Benign, self-limited, idiopathic erythematous maculopapular rash with central pustules; occurs in 30–70% of term newborns within first 72 hours.
🧪 Pathogenesis
Unknown; likely inflammatory reaction to follicular/eccrine gland material. Histology: eosinophilic pustules, no organisms.
Unknown; likely inflammatory reaction to follicular/eccrine gland material. Histology: eosinophilic pustules, no organisms.
🩺 Clinical Features
Erythematous macules/papules with central 1–2 mm pustules; trunk and proximal extremities; palms/soles/mucosa spared. Infant well-appearing, afebrile.
Erythematous macules/papules with central 1–2 mm pustules; trunk and proximal extremities; palms/soles/mucosa spared. Infant well-appearing, afebrile.
⚖️ D/D (dangerous)
Neonatal HSV, congenital candidiasis, staphylococcal pustulosis, scabies, enteroviral vesicles, congenital syphilis rash.
Neonatal HSV, congenital candidiasis, staphylococcal pustulosis, scabies, enteroviral vesicles, congenital syphilis rash.
🕒 Course
Onset: 24–72 h of life; resolves spontaneously within 5–14 days; no scarring or recurrence. No treatment needed.
Onset: 24–72 h of life; resolves spontaneously within 5–14 days; no scarring or recurrence. No treatment needed.
📢 Parental counseling
Reassure that it’s harmless, not contagious, not allergic. No creams or antibiotics needed. Educate on red flags (fever, lethargy, poor feeding).
Reassure that it’s harmless, not contagious, not allergic. No creams or antibiotics needed. Educate on red flags (fever, lethargy, poor feeding).
⭐ High-yield TOACS pearls – Neonatal Rash:
• Always assess the systemic well-being of the infant first. A well infant with classic ETN needs no workup.
• For any vesiculopustular rash in a sick neonate → Rule out HSV (maternal history, Tzanck, PCR).
• Transient neonatal pustular melanosis – present at birth, pustules without erythema, residual hyperpigmentation; common in Black infants.
• Miliaria – due to overheating; clear vesicles (crystallina) or erythematous papules (rubra).
• Congenital candidiasis – presents as widespread erythematous papules/pustules, can be present at birth or within first week; often associated with maternal vaginal candidiasis; treat with topical/immediate antifungals.
• Key message: Erythema toxicum is a diagnosis of reassurance – never dismiss a rash without checking the whole infant.
• Always assess the systemic well-being of the infant first. A well infant with classic ETN needs no workup.
• For any vesiculopustular rash in a sick neonate → Rule out HSV (maternal history, Tzanck, PCR).
• Transient neonatal pustular melanosis – present at birth, pustules without erythema, residual hyperpigmentation; common in Black infants.
• Miliaria – due to overheating; clear vesicles (crystallina) or erythematous papules (rubra).
• Congenital candidiasis – presents as widespread erythematous papules/pustules, can be present at birth or within first week; often associated with maternal vaginal candidiasis; treat with topical/immediate antifungals.
• Key message: Erythema toxicum is a diagnosis of reassurance – never dismiss a rash without checking the whole infant.
🗣️ Candidate Role-Play & Examiner Feedback (TOACS Observed Station)
💬 To the candidate (role-play): You are expected to:
1. Greet the mother, obtain consent, and explain the examination.
2. Perform a focused neonatal examination – assess vital signs, look for distribution of rash, check for systemic illness, examine oral mucosa, palms, soles.
3. Verbally describe the rash: “multiple erythematous macules with central pustules on trunk, infant is alert and well.”
4. State diagnosis: Erythema toxicum neonatorum.
5. Answer examiner questions concisely (see Q&A tab).
6. Counsel parents with empathy: “This is very common, harmless, goes away on its own; no treatment needed. Please watch for fever or lethargy, which would need re-evaluation.”
1. Greet the mother, obtain consent, and explain the examination.
2. Perform a focused neonatal examination – assess vital signs, look for distribution of rash, check for systemic illness, examine oral mucosa, palms, soles.
3. Verbally describe the rash: “multiple erythematous macules with central pustules on trunk, infant is alert and well.”
4. State diagnosis: Erythema toxicum neonatorum.
5. Answer examiner questions concisely (see Q&A tab).
6. Counsel parents with empathy: “This is very common, harmless, goes away on its own; no treatment needed. Please watch for fever or lethargy, which would need re-evaluation.”
📝 Examiner Marking Grid (ETN station – CPSP format):
- ✅ Identifies the rash morphology correctly (macules, papules, central pustules on trunk)
- ✅ Distinguishes benign from serious causes (mentions HSV, candidiasis, miliaria)
- ✅ States ETN as the most likely diagnosis
- ✅ Describes typical age of onset and self-limited course
- ✅ Appropriately avoids unnecessary investigations
- ✅ Provides excellent parental counseling (reassurance, red flags)
- ✅ Demonstrates gentle, respectful communication with mother
- ✅ Summarizes key teaching points: no treatment, benign, good prognosis
- ✅ Mentions that no isolation or discontinuation of breastfeeding needed
📚 Key references: Nelson Textbook of Pediatrics (22nd ed) – Neonatal Dermatology; Remington & Klein’s Infectious Diseases of the Fetus and Newborn; CPSP guidelines on common neonatal problems; Paeds.Online neonatal rash module.
💡 Common candidate pitfalls to avoid:
• Calling it “baby acne” (neonatal acne presents later at 3–4 weeks).
• Prescribing topical steroids or antifungals for ETN.
• Failing to differentiate from HSV – if any maternal history or ill appearance, must investigate.
• Not emphasizing that ETN does NOT require follow-up for the rash itself.
• Forgetting to check palms, soles, and mucous membranes.
• Calling it “baby acne” (neonatal acne presents later at 3–4 weeks).
• Prescribing topical steroids or antifungals for ETN.
• Failing to differentiate from HSV – if any maternal history or ill appearance, must investigate.
• Not emphasizing that ETN does NOT require follow-up for the rash itself.
• Forgetting to check palms, soles, and mucous membranes.