Which radiographic finding is classically associated with beta-thalassemia major?

• A. Hair-on-end appearance
• B. Normal skull
• C. Patchy bone thinning
• D. Enlarged frontal sinus

Answer: (A)

Beta-thalassemia major causes severe, chronic anemia that drives rapid expansion of hematopoietic marrow in the skull. As the marrow fills the diploic spaces, the cranial bones become thinner and the trabeculae align in dense vertical patterns. This remodeling produces the distinctive hair-on-end appearance on skull radiographs, a hallmark radiographic sign of the disease and a result of persistent marrow hyperplasia.

Normal skull anatomy would not show this pattern, and other nonspecific changes like patchy thinning or isolated frontal sinus enlargement lack the characteristic dense, parallel vertical trabeculae seen with marrow expansion.