Abstract Background Interstitial lung disease (ILD) is increasingly observed in patients with systemic inflammatory illnesses, despite the fact that its etiologic attribution in patients on long-term immunomodulator treatment is yet unknown. To demonstrate this diagnostic dilemma, we report a case of chronic ILD in a patient with psoriasis who has been taking Methotrexate (MTX) for a long time. Case Presentation A 61-year-old man with a 20-year history of psoriasis maintained on methotrexate complained of a persistent cough that had persisted for seven months. Subpleural blebs in both upper lobes, bilateral lower-lobe and right middle-lobe interstitial alterations, and characteristics suggestive of chronic ILD were found on the non-contrast chest CT. The patient was lost to follow-up, continued to experience intermittent cough without further treatment. Two months later he developed diffuse neck pain, a palpable mass at the nape, and subsequent diffuse arthralgias. Two days before consult, he developed new-onset sternal chest pain with focal tenderness and a crackling sensation, prompting evaluation at our institution. There was no acute febrile illness, or rapid onset dyspnea. Pulmonary function test demonstrated a restrictive pattern with reduced DLCO. Given the chronic time-course, radiographic fibrotic pattern and lack of typical acute drug-hypersensitivity features, the working diagnosis was an ILD more consistent with psoriasis-associated lung disease than classic MTX-induced pneumonitis, though long-term MTX exposure may have contributed. Discussion MTX-induced lung injury usually manifests acutely or sub-acutely after months of starting treatment, accompanied by dyspnea, cough, fever and ground-glass opacities. It usually improves after cessation of medication. Psoriasis-associated ILD (Ps-ILD), on the other hand, presents with slow progression with subpleural fibrosis or lower-lobe reticulation mimicking nonspecific interstitial pneumonia. Recent studies shows that incidence of ILD increased by 1.5-2 times in patients with psoriatic arthritis, while there is no concrete evidence that prolonged use of MTX causes progressive fibrosis. The following factors tip the scales in favor of psoriasis-associated ILD with a possible MTX contributing effect: the long duration of psoriasis, the extremely long duration of MTX use, the persistent cough, fibrotic features on CT, the absence of acute hypersensitivity symptoms and the presence of subpleural blebs. Treatment and prognosis are affected by this distinction: psoriasis-associated ILD necessitates multimodal approach and potentially antifibrotic or immunomodulatory treatments, whereas MTX should be stopped in cases of suspected drug-induced lung damage.Pulmonary function monitoring, HRCT phenotyping, medication review, early detection, and interdisciplinary management are all required to optimize the results. This abstract is funded by: None
Foscablo et al. (Fri,) studied this question.