Pleural thickening is irreversible and may become progressively worse over time. Symptoms of pleural thickening vary from person to person and depending on the progression of the disease, pleural thickening can be a debilitating disease which can substantially deteriorate the quality of life of the sufferer. Pleural thickening may lead to a condition known as folded lung or rounded atelectasis, in which the pleural thickening compresses the underlying lung and along with the reduced lung function which can result from pleural thickening this can lead to sufferers experiencing tightness of the chest.Reduced air entry on examination is a clinical symptom of pleural thickening. Extensive pleural thickening can also result in blunting of the costophrenic angles i.e. the angles at the place where the ribs meet the diaphragm. For the purposes of qualification for Industrial Injuries Disablement Benefit the diffuse pleural thickening must be severe enough to obliterate the costophrenic angle.Benign pleural conditions such as diffuse pleural thickening and pleural plaques do not turn into mesothelioma but sufferers of diffuse pleural thickening are at an increased risk of developing other asbestos-related conditions, including mesothelioma, asbestos related lung cancer and asbestosis because of their past asbestos exposure.