Differential Diagnosis for an Eight Year Old Afebrile Female with a Sunburn-Looking Diffuse Rash

• Single Most Likely Diagnosis
  • Erythema multiforme: This condition is characterized by a skin rash that can appear as target lesions or a diffuse erythematous rash, often triggered by infections or medications. The sunburn-like appearance and the absence of fever make it a plausible diagnosis.
• Other Likely Diagnoses
  • Contact dermatitis: An allergic reaction to something that came into contact with the skin, such as a plant (like poison ivy) or a chemical, could cause a diffuse rash. The lack of fever and the description of the rash are consistent with this diagnosis.
  • Atopic dermatitis (eczema): Although typically associated with itching and more localized lesions, atopic dermatitis can sometimes present with a more diffuse rash, especially in children.
  • Viral exanthem: Various viral infections can cause rashes in children, and while fever is often present, some cases can be afebrile. The rash's appearance can vary widely.
• Do Not Miss Diagnoses
  • Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN): These are severe skin conditions usually triggered by medications or infections. They can start with a diffuse rash and progress to blistering and peeling of the skin. Although rare, they are medical emergencies due to the risk of severe complications and death.
  • Kawasaki Disease: An acute febrile illness of childhood that can sometimes present without fever early on. It includes symptoms like rash, conjunctivitis, and changes to the lips and oral cavity. It's crucial to consider due to the risk of cardiac complications if untreated.
• Rare Diagnoses
  • Juvenile Dermatomyositis: An autoimmune condition that affects the skin and muscles. It can present with a characteristic heliotrope rash (around the eyes) and Gottron's papules (on the knuckles), but a diffuse rash can also be seen.
  • Systemic Lupus Erythematosus (SLE): A chronic autoimmune disease that can affect various parts of the body, including the skin, joints, and organs. A diffuse rash, especially a malar rash (butterfly-shaped across the cheeks), can be a presenting feature, although it's rare in children.