Differential Diagnosis for Vesicular Rash in Toddler

• Single most likely diagnosis
  • Varicella (Chickenpox): This is the most common cause of a vesicular rash in toddlers, characterized by a pruritic, centrifugal distribution of vesicles in different stages of healing.
• Other Likely diagnoses
  • Herpes Simplex Virus (HSV) infection: Can cause a vesicular rash, often localized to one area of the body, such as the mouth (herpes labialis) or genital area.
  • Hand, Foot, and Mouth Disease (HFMD): Typically caused by Coxsackievirus A, characterized by vesicles on the hands, feet, and inside the mouth.
  • Impetigo: A bacterial infection of the skin that can present with vesicles, although it more commonly presents with honey-colored crusts.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Staphylococcal Scalded Skin Syndrome (SSSS): A severe condition caused by staphylococcal toxins that can lead to widespread skin exfoliation and is life-threatening if not promptly treated.
  • Toxic Epidermal Necrolysis (TEN): A severe skin condition usually triggered by medications, leading to widespread skin necrosis and detachment, which is potentially fatal.
• Rare diagnoses
  • Incontinentia Pigmenti: A rare genetic disorder that can present with a vesicular rash in infancy, often accompanied by other systemic and dermatological manifestations.
  • Acute Hemorrhagic Edema of Infancy: A rare condition characterized by a distinctive pattern of edema and purpura, which can sometimes include vesicles, primarily affecting infants.