How we differentiated cough by virus or by bacteria only on clinical symptom?

Viral versus: Bacterial process can not be determined by symptoms only. Additional information needed to decide.

Not easy: There must be an evaluation of symptom intensity (bacterial usually worse and can be life-threatening and fast evolving). X- rays can help rule out bacterial. A blood white cell count will usually be low or normal with viral. A sputum culture taken to grow out pathogenic bacteria is quite definitive. Viral - itises are usually self-limiting, and antibiotics do not affect viral conditions.