Pink frothy sputum is caused by fluid infiltration from capillaries into the interstitial or alveolar spaces of the lungs. The common clinical forms of pulmonary edema are cardiogenic pulmonary edema and nephrogenic pulmonary edema. How do I diagnose if a patient is coughing up pink foamy sputum? The initial diagnosis of pink foamy sputum symptoms can be based on the color of the sputum. Coughing chocolate colored sputum: reddish-brown or chocolate colored sputum is seen in pulmonary amebiasis caused by an amebic liver abscess that has collapsed into the lungs. Yellow or green mucous sputum: suggests the presence of purulent infection in the respiratory tract. Green sputum is often due to bile, denatured hemoglobin or chlorophyll, and is seen in jaundice, slow-absorbing pneumococcal pneumonia, and pulmonary Pseudomonas aeruginosa infection. Bloody sputum: seen in lung cancer, pulmonary tuberculosis, bronchiectasis. Rust-colored sputum: seen in pneumococcal pneumonia. Pink or bloody foamy sputum: seen in acute pulmonary edema. Jam-like sputum: seen in pulmonary schistosomiasis, gray or black sputum, seen in various kinds of pneumoconiosis, such as coal pneumoconiosis, etc. Brown sputum: seen in pulmonary infarction, pulmonary iron-containing yellow sedimentation.