Acute eosinophilic pneumonia
Acute eosinophilic pneumonia is a rare, acute-onset eosinophilic lung disease.
Acute eosinophilic pneumonia is a rare, rapidly developing form of eosinophilic lung disease, with severity ranging from mild to life-threatening. In this condition, the airways and blood vessels in the lungs are damaged, triggering the release of the inflammatory protein IL-33. This draws eosinophils—a type of white blood cell—into the lungs, where they cause inflammation and symptoms like coughing, shortness of breath, general discomfort, muscle aches, night sweats, and sharp chest pain that worsens with breathing. The exact mechanisms behind the disease are not well understood, but they likely depend on the trigger. Possible causes include smoking, inhaling certain substances, taking specific medications, or having an infection. However, in most cases, no clear cause can be identified, making the disease idiopathic.
- first described
- 1989
- field
- Pulmonology
- known for
- Acute febrile illness with hypoxemia, pulmonary infiltrates, and alveolar eosinophils
- incidence
- 9.1 to 11 per 100,000 person-years (as of 2018)
- reported cases
- Approximately 400 (as of 2018)
- common demographics
- Men ages 20–40, smokers, no history of asthma
Lore & Background
Acute eosinophilic pneumonia was first described in 1989 by Allen, Pacht, Gadek, and Davis, who proposed eight diagnostic criteria: acute febrile illness, hypoxemia, pulmonary infiltrates on imaging, alveolar eosinophils, ruled out infection, ruled out asthma, quick response to steroids, and resolution with no long-term effects. The disease is characterized by airway injury, vascular injury, and release of IL-33, which recruits eosinophils to the lungs. Symptoms are nonspecific and include cough, shortness of breath, malaise, myalgia, night sweats, and pleuritic chest pain, and can progress to acute respiratory distress syndrome (ARDS) and severe hypoxemic respiratory failure requiring mechanical ventilation.
Reader's Guide
Acute eosinophilic pneumonia is significant as a distinct, treatable cause of acute respiratory failure that can mimic other conditions. Its diagnosis requires a comprehensive medical history focusing on smoking history, environmental exposures, and drug use, along with specific criteria including fever ≤1 month, bilateral diffuse opacities on chest imaging, hypoxemia, and ≥25% eosinophils at bronchoalveolar lavage. Corticosteroids are the first-line treatment, with patients typically improving within 48 hours and chest imaging showing dramatic improvement within one month. Relapse is rare. The disease occurs most commonly in men ages 20–40, smokers, and those with no history of asthma, with cases peaking in summer. As of 2018, approximately 400 cases had been reported. Future research is needed on pathogenesis and possible genetic components, as the number of cases compared to cigarette smokers is relatively low.
Did You Know?
- Acute eosinophilic pneumonia was first described in 1989 by Allen, Pacht, Gadek, and Davis.
- Corticosteroids are the first-line treatment, and patients typically improve within 48 hours.
- The disease occurs most commonly in men ages 20–40, smokers, and those with no history of asthma.
- As of 2018, approximately 400 cases of AEP had been reported.
Frequently Asked Questions
Who is Acute eosinophilic pneumonia?
APE is a rare, fast-onset eosinophilic lung condition first formally described in 1989 and classified under pulmonology. Its hallmark presentation is an acute febrile illness paired with hypoxemia, visible pulmonary infiltrates, and a heavy alveolar eosinophil burden.
What are Acute eosinophilic pneumonia's powers/role?
APE injures the airways and small pulmonary vessels, prompting the release of the inflammatory mediator IL-33. That signal floods eosinophils into lung tissue, driving inflammation that manifests as cough, breathlessness, muscle aches, night sweats, and sharp chest pain that worsens with each breath.
How does Acute eosinophilic pneumonia's story end?
Although the onset can be rapid and even life-threatening, most patients recover fully once appropriate treatment is started. The precise long-term mechanisms are still incompletely mapped, but the episode typically resolves rather than scarring the lungs chronically.
Why is Acute eosinophilic pneumonia important?
With roughly 400 reported cases by 2018 and an incidence of about 9–11 per 100,000 person-years, APE is a diagnostically tricky entity that challenges clinicians to distinguish it from other acute lung injuries. It disproportionately strikes men aged 20–40 who smoke and have no prior asthma, giving it a distinctive demographic fingerprint in pulmonology.
When was Acute eosinophilic pneumonia first introduced to the canon?
APE entered the medical literature in 1989 when it was first delineated as a distinct clinical entity. Since that debut it has accumulated a modest but steadily growing body of case reports within the pulmonology field.
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