Differential Diagnosis for Erythematous Sunburn Appearing Diffuse Patch-like Rash in an Afebrile 8-Year-Old Female

• Single Most Likely Diagnosis
  • Sunburn: This is the most likely diagnosis given the description of the rash as erythematous and sunburn-like, especially if the child has been exposed to excessive sunlight without adequate protection.
• Other Likely Diagnoses
  • Contact Dermatitis: This could be a possibility if the child came into contact with an allergen or irritant, leading to a skin reaction that resembles a sunburn.
  • Viral Exanthem: Certain viral infections can cause rashes that might appear similar to sunburn, although these are often accompanied by other symptoms such as fever, which is not present in this case.
  • Photosensitive Reaction: Some medications or conditions can cause the skin to react abnormally to sunlight, leading to a rash that looks like sunburn.
• Do Not Miss Diagnoses
  • Stevens-Johnson Syndrome (SJS): Although rare and usually accompanied by fever and mucous membrane involvement, SJS can present with skin lesions that might initially resemble sunburn. It's a medical emergency due to its potential for severe complications.
  • Toxic Epidermal Necrolysis (TEN): Similar to SJS but more severe, TEN is a life-threatening condition that requires immediate medical attention. Early stages might resemble a severe sunburn.
• Rare Diagnoses
  • Porphyrias: A group of disorders that can cause the skin to be extremely sensitive to sunlight, leading to blistering, scarring, and possibly a rash that could be mistaken for sunburn.
  • Lupus Erythematosus: Systemic lupus erythematosus can cause a photosensitive rash, although it's rare in children and usually accompanied by other systemic symptoms.
  • Erythema Multiforme: A skin condition characterized by target lesions, which might appear after a viral infection or as a reaction to medication. It can sometimes resemble a sunburn in its early stages.