The presence of a radiographic sinusal opacification without any other clinical sign or symptom cannot lead to the diagnosis of "Sinusitis", if considered alone. In a previous paper we observed a high prevalence of patients with both clinical and radiographic signs of sinusitis and a high prevalence of neutrophils in the nasal secretions, now we tried to discover which clinical signs and symptoms are more likely to indicate an acute sinusitis. We compared cough, headache, bacteriological culture of nasal secretions with a sinusal CT scan, without finding any relationship. On the contrary, neutrophils in the nasal secretions and Rx are strictly inter-related with CT scan, with a sensitivity of 77% and a specificity of 100%.