Chronic eosinophilic pneumonia (CEP) is an interstitial lung disorder of unknown etiology (often termed idiopathic CEP in the literature) that is characterized by a profound deposition of eosinophils in the lungs and the subsequent development of symptoms [1] [2] [3] [4] [5]. CEP is most frequently diagnosed in adults around 50 years of age with a significant predilection toward female gender [1]. Although a clear association has not been described, a large number of individuals suffer from asthma or some other form of atopy (such as allergic rhinitis) [1] [2] [3] [4]. Additionally, isolated studies have identified radiation therapy for breast cancer as a possible risk factor [6]. The clinical presentation is distinguished by a cough, wheezing, and progressive dyspnea as main respiratory complaints that may be accompanied by constitutional symptoms - weight loss, fever, and night sweats [1] [3] [6] [7]. In rare cases, massive eosinophilic infiltration can lead to respiratory insufficiency, but most patients suffer from a milder form of the disease [1] [3]. CEP usually has a slow course, and several weeks might pass before the diagnosis is made [1] [2].

A thorough workup is necessary in the case of CEP, encompassing clinical, radiologic, and possibly histopathologic studies. They are all necessary for narrowing the broad differential diagnosis, which includes pulmonary infections (both parasitic and fungal), iatrogenic causes, neoplastic processes, autoimmune vasculitis (Churg-Strauss syndrome), and several other entities that induce pulmonary eosinophilia [1] [2] [7]. Obtaining a complete patient history that will identify basic characteristics of symptoms and their duration is the first step, followed by a detailed personal history. A meticulous physical examination should follow, although lung auscultation may not yield any pathological findings. For this reason, laboratory and imaging studies are the cornerstones in making an initial diagnosis. Detection of peripheral eosinophilia (often exceeding ≥ 1000/mm3) in blood, but also in the bronchioalveolar aspirate (obtained through a bronchioalveolar lavage, or BAL) is a valid diagnostic clue, whereas serum inflammatory markers (erythrocyte sedimentation rate and C-reactive protein), but also immunoglobulin E levels, are often elevated [1] [2] [3]. Conversely, the presence of bilateral infiltrates and ground-glass opacities at the peripheries is typical for CEP, which can be better visualized on computed tomography (CT) compared to standard X-rays of the chest [1] [2] [3] [4] [7]. Although not necessary and now rarely used for confirmation of CEP, bronchoscopy and subsequent biopsy with histopathological examination is useful for excluding other disorders, as the accumulation of eosinophils in the alveoli and the interstitium is the hallmark of CEP [1] [2]. Pulmonary function tests are not always abnormal, but several studies have identified a reduced ability of the lungs to transfer oxygen into the blood, known as the diffusing capacity of the lung for carbon monoxide (DLCO) [2] [4].

The primary treatment for Chronic Eosinophilic Pneumonia is corticosteroids, such as prednisone. These medications help reduce inflammation and the number of eosinophils in the lungs, leading to an improvement in symptoms. The dosage and duration of steroid treatment can vary depending on the severity of the condition and the patient's response to therapy. Some patients may require long-term maintenance therapy to prevent relapses. In cases where corticosteroids are not effective or cause significant side effects, other immunosuppressive medications may be considered.

The prognosis for patients with Chronic Eosinophilic Pneumonia is generally favorable with appropriate treatment. Most patients respond well to corticosteroids, with a significant improvement in symptoms and lung function. However, relapses are common, and some patients may experience recurrent episodes requiring additional treatment. Long-term follow-up is important to monitor for relapses and manage any side effects of treatment. With proper management, many patients can lead normal, active lives.

The exact cause of Chronic Eosinophilic Pneumonia is not well understood. It is believed to be related to an abnormal immune response, possibly triggered by environmental factors, infections, or medications. Some patients with CEP have a history of asthma or other allergic conditions, suggesting a possible link between these conditions. However, the specific triggers and mechanisms leading to the development of CEP remain an area of ongoing research.

Chronic Eosinophilic Pneumonia is a rare condition, with an estimated incidence of less than 1 case per 100,000 people per year. It can occur at any age but is most commonly diagnosed in middle-aged adults. Women are more frequently affected than men. The condition is seen worldwide, but the exact prevalence may vary depending on geographic and environmental factors.

The pathophysiology of Chronic Eosinophilic Pneumonia involves the accumulation of eosinophils in the lung tissue and air spaces. Eosinophils release substances that cause inflammation and damage to the lung tissue, leading to the symptoms of the disease. The reasons for the excessive accumulation of eosinophils in the lungs are not fully understood but are thought to involve an abnormal immune response. This response may be triggered by allergens, infections, or other environmental factors.

Chronic Eosinophilic Pneumonia is a rare lung disease characterized by the buildup of eosinophils in the lungs, leading to inflammation and respiratory symptoms. It is often treated effectively with corticosteroids, although relapses are common. The condition's exact cause is unknown, but it may be related to an abnormal immune response. With appropriate management, patients can achieve good control of symptoms and maintain a good quality of life.

If you have been diagnosed with Chronic Eosinophilic Pneumonia, it's important to work closely with your healthcare provider to manage the condition. Treatment typically involves corticosteroids, which can help reduce inflammation and improve symptoms. Regular follow-up appointments are crucial to monitor your response to treatment and adjust your medication as needed. Be aware of potential triggers, such as allergens or infections, and discuss any concerns or side effects of treatment with your doctor. With proper care, most patients can lead normal, active lives.

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