Las enfermedades pulmonares intersticiales difusas (EPID) son entidades que afectan principalmente a las estructuras alvéolo-intersticiales del pulmón, vasculatura y vías aéreas. Se clasifican en idiopáticas, de etiología conocida y de etiología desconocida. Se manifiestan con disnea y tos, crepitantes secos y síntomas sistémicos. El intercambio gaseoso y los volúmenes pulmonares están disminuidos (patrón restrictivo). Son EPID granulomatosas la granulomatosis sarcoidea necrotizante, la granulomatosis asociada a poliangeítis, la granulomatosis eosinofílica con poliangeítis y la sarcoidosis.

Diffuse interstitial lung disease (DILD) are a group of disorders that involve mainly alveolar interstitium, lung vessels and airways. They are classified as idiopathic, associated with conditions of known aetiology and of unknown aetiology. Clinical manifestations are characterized by dyspnea, cough, dry crackles on auscultation and systemic symptoms. Both gas exchange and lung volumes are reduced (restrictive pattern). Necrotizing sarcoid granulomatosis, granulomatosis with polyangiitis (Wegener's), eosinophilic granulomatosis with polyangiitis and sarcoidosis are grouped as granulomatous DILD.