Rheumatoid lung disease, pneumothorax, and eosinophilia

Four cases of the triad of rheumatoid lung disease, spontaneous pneumothorax, and peripheral blood eosinophilia are reported. Cavitation of a rheumatoid lung nodule caused the pneumothorax in at least 1 case. The significance of eosinophilia and its value as a marker of extra-articular manifestations of rheumatoid disease are discussed.