Ustekinumab Associated with Chronic Eosinophilic Pneumonia.

Kalra, Saminder Singh; Trillo, Cesar; Papierniak, Eric

IntroductionUstekinumab induced eosinophilic pneumonia is rare and to our knowledge, this is the 5th reported case of such an entity.Case StudyA 60-year-old female was admitted with worsening shortness of breath and a non-productive cough for 4 months. Her past medical history was significant for Crohn's disease and psoriatic arthritis that was previously managed with Adalimumab and switched to Ustekinumab 2 months beforesymptoms. Initial diagnostic workup showed 10% peripheral eosinophilia and a CT chest showed numerous 5 mm nodules scattered throughout the lungs along with some peripheral reticulations.Her BAL fluid analysis showed abnormally high eosinophil count (67%), greatly limiting her potential diagnoses to eosinophilic pneumonia, EGPA, and tropical pulmonary eosinophilia (TPE). AEP typically causes more severe disease with a rapid onset and there was low suspicion for TPE based on history, leaving EGPA and CEP.Based on her negative autoimmune serology, a negative biopsy of the nasal mucosa (no vasculitis/granulomata or eosinophils), and negative infectious workup, the patient was diagnosed with CEP secondary to Ustekinumab and the drug was stopped. She was started on high dose prednisone and after a prolonged taper over 5 months, her symptoms and nodules and reticulations on her CT scan resolved.DiscussionThis case exemplifies the importance of identifying drug-induced lung diseases which in many cases might not have a strong temporal association with the symptom onset. It also highlights that some drugs owing to their long elimination half-time can remain in the system for a prolonged period and continue to cause symptoms despite their cessation and require prolonged treatment and reassurance.ConclusionThe association of eosinophilic pneumonia with Ustekinumab, a drug used in the treatment of psoriasis and other autoimmune diseases, is rare and there is a paucity of literature regarding this association.