What are the types, causes, and management of rashes in infants?

Types of Infant Rashes: Causes and Management

Common Benign Newborn Rashes (0-4 weeks)

Erythema Toxicum Neonatorum

This is the most common benign newborn rash, presenting as erythematous macules, papules, and pustules on the face, trunk, and extremities. 1, 2

• Appearance: Multiple uniform lesions that are very similar in shape and size 3
• Timing: Appears in first few days of life 1
• Management: Resolves spontaneously within 1 week; parental reassurance only 1, 2

Transient Neonatal Pustular Melanosis

• Appearance: Vesiculopustular rash that can be diagnosed clinically based on distinctive appearance 1
• Management: Self-limited; observation only 1

Milia

• Appearance: Tiny white papules, typically on face 1
• Cause: Immaturity of skin structures 1
• Management: Resolves spontaneously without intervention 1, 2

Miliaria (Heat Rash)

• Appearance: Tiny vesicles or papules caused by sweat retention 1, 2
• Management: Cooling measures (remove excess clothing, avoid overheating); resolves spontaneously 1, 2

Neonatal Acne (Birth to 6 weeks)

• Appearance: Comedones or erythematous papules on face, scalp, chest, and back 2
• Management: Typically resolves spontaneously; failure to resolve within 1 year warrants evaluation for androgen excess 2

Neonatal Cephalic Pustulosis

• Cause: Hypersensitivity to Malassezia furfur 2
• Management: Self-limited; severe cases treated with topical ketoconazole 2

Diaper Dermatitis

Contact Diaper Dermatitis

• Appearance: Erythema in diaper area, sparing skin folds 2
• Management: Keep diaper area clean, open air exposure, frequent diaper changes 2
• Topical treatment: Zinc oxide protects and helps treat diaper rash 4

Candidal Diaper Dermatitis

• Appearance: Bright red rash with satellite lesions, involving skin folds 2
• Management: Topical antifungals 2
• Warning: Do not use hydrocortisone for diaper rash without consulting a doctor 5

Atopic Dermatitis (Eczema)

Atopic eczema requires pruritus (or report of scratching in a child) plus three or more of the following: involvement of flexural areas, personal or family history of atopy, dry skin, and visible eczema. 6, 3

Clinical Features

• Age of onset: Before 6 months suggests atopic dermatitis 3
• Distribution: Flexural areas in older infants; cheeks, forehead, and outer limbs in children under 4 years 6, 3
• Key symptom: Pruritus with scratching or rubbing (mandatory criterion) 6, 3
• Associated features: Family history of asthma or hay fever 6, 3

Management

• First-line: Liberal use of emollients in adequate amounts 6
• Topical corticosteroids: Consider age, site, and extent of disease when prescribing 6
  • For children under 2 years: Ask a doctor before using hydrocortisone 5
  • For children 2 years and older: Apply hydrocortisone to affected area not more than 3-4 times daily 5
• Avoid contact with eyes when using topical steroids 5

Critical Complication: Eczema Herpeticum

This is a medical emergency requiring immediate systemic antiviral therapy with acyclovir, as it may progress rapidly to systemic infection. 7

• Recognition: Multiple uniform "punched-out" erosions or vesiculopustular eruptions that are very similar in shape and size 7
• Additional treatment: Empirical antibiotics (cephalexin or flucloxacillin) may be added to cover secondary bacterial infection 3, 7
• Diagnostic test: Tzanck smear if herpetic infection suspected 3

Seborrheic Dermatitis

• Appearance: Scaling on the scalp ("cradle cap") 2
• Distribution: Can also affect trunk and extremities 1
• Management:
  • Shampooing and removing scales with soft brush after applying mineral oil or petrolatum 2
  • Severe cases: Tar-containing shampoo, topical ketoconazole, or mild topical steroids 6, 2

Infectious Rashes Requiring Urgent Evaluation

When to Suspect Infection

• Signs of secondary bacterial infection: Crusts, discharge, erosions 3
• Deterioration of previously stable eczema: Suggests secondary infection requiring bacterial and viral cultures 3
• Systemic symptoms: Fever, irritability, poor feeding 8

Roseola (HHV-6)

• Key feature: High fever for 3-5 days, followed by rash appearing after fever resolves 8, 9
• Appearance: Pink maculopapular rash on trunk spreading to extremities 8

Scarlet Fever

• Appearance: Rash develops on upper trunk, spreads throughout body, sparing palms and soles 8
• Associated features: Fever, strawberry tongue, sandpaper-textured rash 8

Critical Diagnostic Pitfalls

Do Not Miss These Conditions

1. Herpetic infection (eczema herpeticum): Requires Tzanck smear and urgent antiviral treatment 3
2. Meningococcal infection: Can begin as maculopapular rash and progress to petechial rash; progresses more rapidly than Rocky Mountain spotted fever 6
3. Neonatal pustules: Always require investigation to exclude infectious disease 3

Key Distinguishing Features

• Duration of individual lesions:
  • Ordinary urticaria: 2-24 hours 6
  • Contact urticaria: Up to 2 hours 6
  • Urticarial vasculitis: Days 6
• Pruritus present: Atopic dermatitis, pityriasis rosea, molluscum contagiosum, tinea 8
• Fever present: Roseola, erythema infectiosum, scarlet fever 8

When to Refer to Specialist

Refer when there is diagnostic doubt, failure to respond to mildly potent steroids in children, need for second-line treatment, or when specialist opinion would be valuable in counseling. 6

• Failure to respond: To maintenance treatment with mildly potent steroids in children or moderately potent steroids in adults 6
• Dietary manipulation being considered: Requires professional supervision 6
• Severe or persistent cases: Requiring second-line treatment 6