On physical exam:
Bright red, sharply demarcated,<unk>  rash
Spead to the vulva or penis
Subcutaneous involvement suggestive of cellulitis is normally absent
Absence of systemic signs of infection
Perianal streptococcal dermatitis
Atopic dermatitis
Trichinosis
Diaper dermatitis
Contact vulvovaginitis
Erythema toxicum neonatorum
Acrodermatitis enteropathica
Neonatal acne