What is the treatment for a 2-month-old baby with red bumps on the scalp?

Red Bumps on Scalp in a 2-Month-Old Infant

The most likely diagnosis is seborrheic dermatitis (cradle cap), which should be managed with gentle shampooing and scale removal using mineral oil or petrolatum, with ketoconazole shampoo reserved for severe cases. 1

Initial Diagnostic Approach

The age of onset and distribution pattern are critical for narrowing the differential diagnosis in this age group:

• Onset before 6 months suggests either seborrheic dermatitis, atopic dermatitis, or neonatal pustular conditions 2
• Scalp-predominant distribution strongly favors seborrheic dermatitis over atopic dermatitis, which typically spares the scalp and affects flexural areas 3, 2

Key Distinguishing Features to Assess

Seborrheic Dermatitis (Most Likely)

• Greasy, yellowish scaling on the scalp with or without erythema 1
• Typically not pruritic (unlike atopic dermatitis) 3
• May extend to face, neck, and diaper area 1
• Onset typically in first few months of life 4

Atopic Dermatitis (Less Likely at This Age/Location)

• Obligatory pruritus must be present for diagnosis 2
• Typically affects flexural areas (antecubital/popliteal fossae), not scalp 3, 2
• Associated with dry skin and family history of atopy 3

Neonatal Pustular Conditions (If Pustules Present)

• Neonatal cephalic pustulosis: caused by Malassezia furfur hypersensitivity, presents on face and scalp with pustules 1, 4
• Erythema toxicum neonatorum: typically resolves within first week of life 1, 4
• Transient neonatal pustular melanosis: self-limited, resolves spontaneously 4, 5

Treatment Algorithm for Seborrheic Dermatitis

First-Line Management

• Daily shampooing with gentle baby shampoo 1
• Apply mineral oil or petrolatum to soften scales, leave on briefly, then remove with soft brush 1
• This approach is sufficient for mild to moderate cases 1

Second-Line for Severe Cases

• Ketoconazole 2% shampoo or tar shampoo for refractory cases 1
• Apply once daily to affected areas 6
• Continue for 2-4 weeks or until clinical clearing 6
• Topical ketoconazole cream 2% can be applied once daily if shampoo formulation is insufficient 6, 1

When to Consider Topical Corticosteroids

• Low-potency topical steroids only if significant inflammation is present 1
• Avoid high-potency steroids on infant scalp due to absorption risk 7, 8
• Use sparingly and for limited duration to prevent skin atrophy 8

Critical Pitfalls to Avoid

• Do not use salicylic acid in infants due to risk of systemic absorption and salicylism 3
• Avoid lindane completely in neonates - it is contraindicated and has CNS toxicity risk 3
• Do not assume infection without appropriate clinical features; most neonatal scalp eruptions are benign and self-limited 4, 5
• Reassess diagnosis if condition does not respond to standard seborrheic dermatitis treatment within 2-4 weeks 6

When to Obtain Laboratory Confirmation

If the presentation is atypical or unresponsive to treatment:

• Scalp scraping with KOH preparation to rule out tinea capitis (though rare at this age) 3
• Fungal culture if dermatophyte infection suspected 3
• Consider bacterial culture if pustules are present and infection is suspected 5

Red Flags Requiring Further Evaluation

• Systemic symptoms: fever, poor feeding, lethargy suggest infection requiring urgent evaluation 3
• Failure to respond to appropriate treatment after 4 weeks 6
• Severe inflammation with erosions or crusting 3
• Associated lymphadenopathy (consider Gianotti-Crosti syndrome or infection) 9