What clinical sign commonly indicates neutropenia?

• A. Rash
• B. Fatigue
• C. Fever and increased infection risk; absolute neutrophil count < 1.5 x 10^9/L
• D. Headache

Answer: (C)

When neutrophils are low, the body’s first line of defense against bacteria is diminished, so infections can occur with fewer or less obvious local signs. Fever becomes a key clinical clue because it often marks an infection even when other inflammatory signs are blunted. Neutropenia is defined by an absolute neutrophil count below 1.5 x 10^9/L, and fever in this setting is especially worrisome and clinically actionable.

So the best choice combines the typical clinical sign (fever indicating possible infection) with the lab finding that confirms neutropenia. The other symptoms—rash, fatigue, and headache—are nonspecific and don’t specifically indicate neutropenia or its infection risk.