Introduction: Post-COVID interstitial lung disease (ILD) may progress to a progressive fibrotic phenotype in some patients and overlap with other fibrotic ILD subtypes. This overlap complicates diagnostic differentiation and directly influences treatment strategies.

Clinical Case Description: A 62-year-old male presented with exertional dyspnea and dry cough. His history included COVID-19 pneumonia in 2021 requiring hospitalization. Since March 2023, he had been followed with a diagnosis of ILD and treated with nintedanib followed by pirfenidone; he has received no treatment for the past four months. He has been on long-term oxygen therapy for three years. Occupational history revealed 7–8 years of work in the textile industry with dust exposure.

Pulmonary function tests showed a marked restrictive pattern with FVC 35%, FEV1 39%, and FEV1/FVC 85%. High-resolution computed tomography (HRCT) demonstrated bilateral reticular opacities, traction bronchiectasis, and prominent areas of mosaic attenuation. Rheumatologic markers were negative.

The case was evaluated in a multidisciplinary ILD board, and an overlap phenotype of post-COVID fibrotic ILD and fibrotic hypersensitivity pneumonitis (HP) was considered most likely. Antifibrotic and immunosuppressive therapy was planned.

Conclusions: This case highlights that post-COVID fibrotic lung disease may represent a complex entity that overlaps with other fibrotic ILD subtypes, such as fibrotic hypersensitivity pneumonitis, rather than a single phenotype. The mosaic attenuation pattern on HRCT, significant occupational dust exposure, and progressive functional decline strongly support fibrotic HP, while prior COVID-19 infection supports a post-infectious fibrotic process. The variable response to antifibrotic therapy further supports this heterogeneous phenotype. Therefore, a multidisciplinary approach integrating clinical, radiological, and exposure history is crucial for accurate phenotyping and optimal treatment strategy.