What is the most likely pathogen responsible for a 5-year-old boy's presentation of low-grade fever, sore throat, rash on the buttocks, hands, and feet, and oral vesicles, with a temperature of 38.3°C, tachycardia, and normal blood pressure?

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Differential Diagnosis

  • Single most likely diagnosis
    • C. Coxsackie A virus: This is the most likely diagnosis due to the presence of oral vesicles and a rash on the hands, feet, and buttocks, which is consistent with Hand, Foot, and Mouth Disease (HFMD), a common illness caused by Coxsackie A virus.
  • Other Likely diagnoses
    • E. Human herpes virus 6: This virus can cause roseola, which is characterized by a high fever and a rash that appears after the fever resolves. However, the presence of oral vesicles is not typical for roseola.
    • A. Herpes simplex virus 1: Although HSV-1 can cause oral vesicles, it typically does not cause a rash on the hands and feet.
  • Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
    • B. Varicella zoster virus: Although the rash is not typical for chickenpox, it's essential to consider this diagnosis due to the potential severity of the illness, especially if the child is immunocompromised.
    • G. Epstein-Barr virus: EBV can cause infectious mononucleosis, which can present with a sore throat and fever. Although a rash is not a typical symptom, it can occur, especially if the patient is taking certain medications like ampicillin.
  • Rare diagnoses
    • D. Rubella virus: Rubella is a rare illness in countries with widespread vaccination, and the symptoms do not perfectly match the presentation of rubella.
    • F. Parvovirus B19: This virus can cause erythema infectiosum (Fifth disease), which is characterized by a "slapped cheek" appearance and a lacy rash on the body. However, the presence of oral vesicles and the specific distribution of the rash make this diagnosis less likely.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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