Increased lung markings are a common finding on a chest X-ray or CT scan.

The chest cavity houses several important structures, including the pulmonary arteries, pulmonary veins, trachea, and bronchi. On imaging, these structures appear as shadows resembling an upside-down tree. This pattern is referred to as lung markings. An increase in the prominence of these shadows is described as increased lung markings.

Causes

Increased lung markings can arise from various causes.

They may often be seen in healthy individuals. For example, they can simply reflect increased blood flow to the lungs, which is often normal, particularly in specific groups such as children, older adults, people who are overweight, and pregnant women. Similarly, lung congestion following exercise may also appear as increased markings.

Furthermore, long-term smoking can contribute to increased markings.

Some lung diseases can also cause increased markings. Common examples are chronic bronchitis, bronchiectasis, chronic obstructive pulmonary disease (COPD), and interstitial lung disease. These conditions can cause impaired mucus clearance (stasis), recurrent inflammation, or coughing, leading to congestion and edema of the airway walls and tissues, which thickens the markings on images.

Additionally, some heart conditions, such as left heart failure or other causes of left-sided heart dysfunction, can cause pulmonary edema, also resulting in increased lung markings.

Treatment

Typically, if increased lung markings are an incidental finding without associated symptoms, they do not necessarily indicate a significant health issue. Therefore, treatment is usually not required, though follow-up imaging may be recommended in some cases.

When symptoms like cough and sputum are present, increased markings are frequently caused by inflammation, though other conditions may be responsible. Diagnosing the underlying cause requires a comprehensive evaluation, including medical history, physical examination, laboratory tests, and further imaging studies. Consulting a healthcare provider is recommended for symptomatic individuals to determine appropriate management.