Idiopathic chronic eosinophilic pneumonia (ICEP), also known as Carrington's disease, is a rare eosinophilic lung disorder characterized by pulmonary infiltrates with no identifiable cause. We report the case of a 59-year-old man with no significant medical history who presented with an eight-month history of progressive exertional dyspnea and a non-productive cough. Chest imaging showed bilateral peripheral ground-glass opacities. Laboratory evaluation revealed peripheral blood eosinophilia (2,000/mm³), and bronchoalveolar lavage demonstrated eosinophilic alveolitis (30%). The patient was treated with oral corticosteroids, resulting in complete symptom resolution and marked radiological improvement.

Idiopathic chronic eosinophilic pneumonia (ICEP) often relapses upon corticosteroid tapering. Biologics targeting interleukin-5 (IL-5) are effective, but optimal dosing intervals remain unclear. We report a case of relapsing ICEP in a patient in her 50s. Mepolizumab, an IL-5 ligand blocker, failed to maintain remission, with clinical relapse occurring 4 months after initiation. Switching to benralizumab, an interleukin-5 receptor blocker, induced rapid and deep eosinophil depletion. For optimising dosing, treatment was temporarily withheld, revealing a prolonged remission duration of 8 months before eosinophil recovery and clinical relapse. Based on these kinetics, a 6-monthly benralizumab maintenance strategy was established. The patient has remained relapse-free with zero eosinophils for over 2 years under this biannual regimen. This case suggests that benralizumab offers superior durability compared to mepolizumab in CEP due to deep depletion, enabling an extended, cost-effective dosing interval guided by individual eosinophil recovery kinetics.

Eosinophilic pneumonia is rare and characterized by excessive accumulation of eosinophils in the alveolar macrophages and interstitium. The presentation can be acute or chronic. The patient can also present with respiratory failure requiring intensive support. These patients may have bronchial asthma at presentation or may be diagnosed with the same later. Diffuse alveolar haemorrhage, a rare complication of idiopathic chronic eosinophilic pneumonia, is life-threatening requiring urgent and aggressive investigation and management. We report a young male who had pneumonia and haemoptysis and was diagnosed to have idiopathic chronic eosinophilic pneumonia and diffuse alveolar haemorrhage.

Our patient is an 80-year-old woman with chronic eosinophilic pneumonia (CEP), chronic urticaria (CU), severe persistent asthma (SPA), long-term oral corticosteroid therapy, and a resected papillary thyroid carcinoma. The patient had normal, stable immunoglobulin E (IgE) levels across all treatments ranging from 16 to 37 IU/mL. In treating her CEP and severe asthma, she trialed monoclonal antibody therapy with mepolizumab, benralizumab, dupilumab, and omalizumab, which were each begun and then discontinued successively due to severe side effects or allergic reaction. However, reslizumab offered 10 months of notable relief from urticaria and dyspnea without oral corticosteroids but was discontinued after the patient developed infusion-associated urticaria. Given her relief with reslizumab, we planned to desensitize her to this medication via a stepwise, slowed infusion up to a target therapeutic dose. Complete vital signs and physical exam looking for symptoms of an allergic response, including angioedema, urticaria, dyspnea, and nausea, were performed every 15 minutes. Our patient was successfully desensitized to reslizumab at a target dose of 195 mg over three hours. Vitals were checked every 15 minutes, which were within normal limits throughout. Further, she was monitored for any symptoms of allergic reaction, including angioedema, nausea, urticaria, and dyspnea, and denied any complaints throughout the procedure. Our patient reported notable relief of dyspnea and fatigue at two weeks and four weeks post-procedure. As opposed to a decrease in dose or discontinuation of treatment, patients may undergo rapid desensitization through a stepwise, slowed infusion rate to better tolerate a previously allergenic medication.

The efficacy of mepolizumab as an alternative to glucocorticoids for treating idiopathic chronic eosinophilic pneumonia (ICEP) has been reported. However, various questions remain unanswered, such as the most appropriate dose and dosage interval of mepolizumab for ICEP, how long efficacy is maintained, how long administration should be continued, and whether and when discontinuation can be considered. We present herein three cases of refractory ICEP treated with mepolizumab at a dose of 100 mg every 4 or 8 weeks. No recurrences were observed after 77 months of treatment in Case 1 and after 45 months in Case 2. Case 3 was treated with mepolizumab for 33 months, but ICEP relapsed 42 months after discontinuation of mepolizumab. In conclusion, mepolizumab for refractory ICEP should be continued for as long as possible, considering disease status, glucocorticoid-related adverse events, and the financial situation of the patient.