'Hair-on-end' sign: an important finding in clinical practice.
A 35-year-old African-American female with significant medical history for asthma, chronic anemia and status post-splenectomy was admitted for marked anemia and dizziness. Her family history was unremarkable for hemoglobinopathies. A computed tomography of head without contrast revealed thickening of the calvarium with ‘hair-on-end’ appearance and enlarged opacified maxillary and sphenoid sinuses, completely filled with blood (Figure 1). Hemoglobin electrophoresis analysis revealed the following hemoglobin fractions Hb F 80%, Hb A1 16.6%, Hb A2 2.8% and Hb …