A 2-day-old infant presents with flesh-colored papules on the face and trunk on an erythematous base; lesions contain eosinophils. What is the most likely diagnosis?

A 2-day-old infant presents with flesh-colored papules on the face and trunk on an erythematous base; lesions contain eosinophils. What is the most likely diagnosis?

• A. Neonatal herpes simplex infection
• B. Erythema toxicum neonatorum
• C. Erythema multiforme
• D. Congenital ichthyosis

Answer: (B)

Erythema toxicum neonatorum is the classic diagnosis when a newborn presents in the first days of life with small flesh-colored papules on an erythematous base, and the lesions contain eosinophils. This rash commonly appears within 24 to 72 hours after birth, can involve the face and trunk, and is benign and self-limited, typically resolving within a week or two without treatment. The presence of eosinophils in the pustules helps distinguish it from other neonatal eruptions. Neonatal herpes simplex infection would usually show vesicles that can be grouped and may be accompanied by fever or irritability and sometimes mucosal involvement, and it requires antiviral therapy pending confirmation. Erythema multiforme presents with target-like lesions, often on the hands and feet and sometimes mucosal involvement, and is not a newborn-compatible presentation. Congenital ichthyosis involves persistent dry, scaly skin from birth rather than pustular, eosinophil-rich lesions. So the described clinical picture fits erythema toxicum neonatorum — a common, benign neonatal rash with eosinophils in the lesions.

Erythema toxicum neonatorum is the classic diagnosis when a newborn presents in the first days of life with small flesh-colored papules on an erythematous base, and the lesions contain eosinophils. This rash commonly appears within 24 to 72 hours after birth, can involve the face and trunk, and is benign and self-limited, typically resolving within a week or two without treatment. The presence of eosinophils in the pustules helps distinguish it from other neonatal eruptions.

Neonatal herpes simplex infection would usually show vesicles that can be grouped and may be accompanied by fever or irritability and sometimes mucosal involvement, and it requires antiviral therapy pending confirmation. Erythema multiforme presents with target-like lesions, often on the hands and feet and sometimes mucosal involvement, and is not a newborn-compatible presentation. Congenital ichthyosis involves persistent dry, scaly skin from birth rather than pustular, eosinophil-rich lesions.

So the described clinical picture fits erythema toxicum neonatorum — a common, benign neonatal rash with eosinophils in the lesions.