Differential Diagnosis for Abdominal Rash in a 12-year-old Girl

The patient presents with a vesicular rash on the abdomen. Considering the age and presentation, the following differential diagnoses are possible:

• Single most likely diagnosis
  • Varicella (Chickenpox): This is a common childhood illness characterized by a vesicular rash, which can appear anywhere on the body, including the abdomen. The rash typically starts on the trunk and spreads to other areas. Given the age of the patient and the nature of the rash, varicella is a strong consideration.
• Other Likely diagnoses
  • Contact Dermatitis: This condition can cause a vesicular rash if the skin comes into contact with an allergen or irritant. It's possible that the girl came into contact with something that caused a localized reaction on her abdomen.
  • Herpes Zoster (Shingles): Although less common in children, herpes zoster can cause a vesicular rash that is usually confined to one area of the body, such as the abdomen. It's a consideration, especially if the child has had varicella in the past or has been immunocompromised.
  • Impetigo: This is a bacterial skin infection that can cause vesicles or pustules, often starting around the mouth or nose but can spread to other areas, including the abdomen. It's contagious and common in children.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN): These are severe skin conditions usually triggered by medications or infections. They can start with a vesicular rash and progress to widespread skin necrosis and detachment. Early recognition is crucial for management and preventing severe outcomes.
  • Primary Herpes Simplex Virus (HSV) Infection: While more commonly associated with oral or genital lesions, HSV can cause a vesicular rash at any site, including the abdomen, especially in immunocompromised individuals.
• Rare diagnoses
  • Pemphigus Vulgaris: An autoimmune disease that causes blistering of the skin and mucous membranes. It's rare in children but could present with a vesicular rash.
  • Bullous Pemphigoid: Another autoimmune blistering disease that is rare in children but could be considered in the differential diagnosis of a vesicular rash.
  • Zinc Deficiency (Acrodermatitis Enteropathica): A rare genetic disorder that leads to zinc deficiency, causing skin lesions, including vesicles, among other symptoms.

Each of these diagnoses has different implications for treatment and management, emphasizing the importance of a thorough diagnostic workup.