A 4-year-old girl with chickenpox was noted to have fresh vesicles appearing yesterday. She is afebrile today and eating well. Her mother asks when she can safely return to school. The child may return when:
- A The last fresh vesicle has appeared
- B All lesions have crusted over ✓
- C Five days have passed since the first lesion appeared
- D All scabs have separated and fallen off
Correct answer: B. All lesions have crusted over
Explanation
A patient with varicella is infectious from 1 to 2 days before the rash until every lesion has crusted, usually 5 to 6 days after onset in immunocompetent children. Crusting marks the end of infectivity because vesicle fluid contains the virus while scabs do not. Waiting for scab separation, option D, unnecessarily prolongs exclusion by several weeks.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.