Limited thickening of the pleura of both lungs may be caused by pleurisy, pleural effusion, tuberculosis and so on. 1. Pleurisy: the stimulation of inflammation will cause abnormal proliferation of granulation tissue in the pleura, which will lead to limited thickening of pleura. 2. Pleural effusion: when there is effusion in the pleural cavity, the fibrin in the effusion will be deposited on the pleura, which will cause the proliferation of granulation tissue, thus leading to limited thickening of the pleura. 3. Tuberculosis: tuberculous pleurisy will lead to inflammatory exudation, and the sugar and protein components in the large amount of exudate will be deposited on the pleura, which will lead to limited thickening of the pleura. If you have limited thickening of pleura in both lungs, you need to go to the hospital in time for relevant examination to find out the cause of the disease and actively cooperate with the doctor for treatment.