A 5-year-old unimmunised child has fever for 3 days, coryza, conjunctivitis, and a blotchy maculopapular rash starting at the hairline. Koplik's spots are seen on the buccal mucosa. Which immunological defect is the most important complication following measles infection?
- A Lymphopenia with measles-induced 'immune amnesia' depleting memory B and T cells ✓
- B Persistent B-cell immunodeficiency
- C IgA deficiency causing recurrent sinopulmonary infections
- D Complement C3 deficiency
Explanation
Measles causes profound and prolonged immunosuppression through multiple mechanisms. The most critical is 'immune amnesia' — measles virus infects and destroys memory B and T lymphocytes (including pre-existing vaccine-induced memory cells), potentially wiping out years of protective immunity acquired before the measles infection. This increases susceptibility to a wide range of secondary infections for 2–3 years after recovery. Lymphopenia is characteristic during acute measles. Koplik's spots (pathognomonic) appear before the rash. Vitamin A supplementation reduces measles morbidity and mortality.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.