Differential Diagnosis for a 2-Week-Old with Large Bullae
Single Most Likely Diagnosis
- Epidermolysis Bullosa (EB): A group of genetic conditions that result in fragile skin and mucous membranes, leading to the formation of bullae. The absence of a history of STD or reproductive tract infections in the mother and the presence of large bullae in a newborn make EB a strong consideration.
Other Likely Diagnoses
- Staphylococcal Scalded Skin Syndrome (SSSS): Caused by staphylococcal toxins that lead to exfoliation and bullae formation. It's a common cause of bullous lesions in infants.
- Congenital Impetigo: A bacterial infection of the skin that can cause bullae, though it's less common in the first two weeks of life.
- Incontinentia Pigmenti: A genetic disorder that affects the skin, hair, teeth, and nails, and can present with bullous lesions at birth or shortly after.
Do Not Miss Diagnoses
- Herpes Simplex Virus (HSV) Infection: Although the mother has no history of STDs, neonatal HSV can be acquired during delivery from an asymptomatic mother. It's crucial to consider due to its high morbidity and mortality if left untreated.
- Sepsis: Bacterial sepsis can cause a wide range of skin manifestations, including bullae, and is a medical emergency.
Rare Diagnoses
- Autoimmune Bullous Diseases: Such as pemphigus or pemphigoid, which are extremely rare in neonates but can present with bullae.
- Erythema Multiforme: A skin condition characterized by target lesions, which can occasionally include bullae, though it's uncommon in newborns.
- Bullous Mastocytosis: A rare condition associated with mast cell proliferation and can present with bullae, though it's exceptionally rare in neonates.