OVERVIEW

What is pulmonary aspergillosis?

Pulmonary aspergillosis refers to a lung disease caused by infection with *Aspergillus* (a type of fungus).

*Aspergillus* is a fungus (also called mold) commonly found in the environment, such as in soil, plants, and decaying organic matter. People often inhale *Aspergillus* spores. In healthy individuals, *Aspergillus* usually does not cause infections or other health problems. However, for those with weakened immune systems or underlying lung diseases, *Aspergillus* can lead to illness.

For some people, the spores trigger an allergic reaction, known as allergic bronchopulmonary aspergillosis (ABPA). Others may develop mild to severe lung infections after inhaling the spores. The most severe form of *Aspergillus* infection is invasive aspergillosis, where the fungus invades blood vessels and spreads to organs outside the lungs, such as the skin, brain, eyes, liver, and kidneys [1].

Is pulmonary aspergillosis common?

Pulmonary aspergillosis is relatively rare in the general population but occurs more frequently in high-risk groups. Among fungal lung infections, aspergillosis is the most common, and its incidence is increasing.

Conservative estimates suggest there are approximately 290,000 cases of chronic pulmonary aspergillosis (CPA) and 4.84 million cases of ABPA worldwide, including about 40,000 CPA cases and 490,000 ABPA cases in China. Europe has around 60,000 cases of invasive pulmonary aspergillosis (IPA), while China has at least 160,000 IPA cases.

Invasive aspergillosis is a severe and often fatal infection, with a global mortality rate of about 30%–95% and a mortality rate of 39%–100% in China. The mortality rate depends largely on underlying conditions, infection sites, treatment, and drug resistance [2].

What are the types of pulmonary aspergillosis?

Pulmonary aspergillosis is primarily caused by *Aspergillus fumigatus* and includes a spectrum of clinical syndromes: chronic pulmonary aspergillosis (CPA), invasive pulmonary aspergillosis (IPA), and allergic bronchopulmonary aspergillosis (ABPA). The interaction between *Aspergillus* and the host's immune system (either hyperactive or impaired) determines which clinical syndrome is more likely to develop [3].

• Chronic pulmonary aspergillosis (CPA): Typically occurs in patients with normal or mildly impaired immune systems and underlying lung diseases, such as chronic obstructive pulmonary disease (COPD), post-tuberculosis sequelae, non-tuberculous mycobacterial infections, or lung cancer. Clinical manifestations vary, ranging from simple aspergillomas to chronic cavitary and fibrotic lesions.
• Invasive pulmonary aspergillosis (IPA): A severe infection usually seen in immunocompromised patients, such as those undergoing treatment for hematologic malignancies, hematopoietic stem cell transplantation, or solid organ transplantation.
• Allergic bronchopulmonary aspergillosis (ABPA): An allergic reaction to *Aspergillus*, typically occurring in individuals with asthma or cystic fibrosis.

Which department should I visit for pulmonary aspergillosis?

In general hospitals, you can seek treatment from the respiratory medicine or infectious diseases department. If you have a fever, you may visit the fever clinic.

In severe cases, *Aspergillus* infections can affect other organs outside the lungs, such as the skin, central nervous system, eyes, liver, and kidneys. If you experience related symptoms (e.g., nasal congestion, eye pain, facial pain, headache), you should consult departments such as otolaryngology, ophthalmology, neurology, or nephrology.

SYMPTOMS

What are the common manifestations of pulmonary aspergillosis?

In general, the common manifestations of pulmonary aspergillosis include the following:

• Respiratory symptoms: including cough, sputum production, hemoptysis, dyspnea, tachypnea, chest pain, etc.
• Fever: Patients with pulmonary aspergillosis often develop fever, usually in cases of concurrent infections, severe infections, critical illness, or invasive aspergillosis.
• Hemoptysis: Some patients may experience hemoptysis, as Aspergillus can invade blood vessels in the lungs. This can range from mild blood-streaked sputum to life-threatening massive hemoptysis.
• Systemic symptoms: including fatigue, loss of appetite, weight loss, sweating, etc.
• Changes in pulmonary imaging: Chest X-rays or CT scans may reveal findings such as "aspergilloma," cavities, nodules, fibrosis, consolidation, peribronchial infiltration, shadows, atelectasis, or bronchiectasis. The imaging manifestations of pulmonary aspergillosis are highly variable, and clinicians need to integrate additional information for comprehensive assessment.
• Manifestations in other sites: Invasive aspergillosis can disseminate to organs outside the lungs, including the skin, brain, eyes, liver, and kidneys. Symptoms such as nasal congestion, facial pain, eye pain, vision problems, eye protrusion or swelling, seizures, or rashes with spots (possibly with central blackening) may occur [4].

CAUSES

What are the causes of pulmonary aspergillosis?

Aspergillus is a common and widely distributed fungus (mold) found in soil, plants, and decaying organic matter in the natural environment.

Humans are primarily infected by inhaling large amounts of dust containing Aspergillus spores through the respiratory tract. Some patients may become infected through direct contact with Aspergillus via broken skin.

Aspergillus causes disease in two main ways:

• One is an allergic reaction. Healthy individuals can effectively clear fungal spores after inhalation, but those with allergies may experience a strong immune response to Aspergillus spores or hyphae, leading to allergic aspergillosis.
• The other is invasive infection. People with normal immune systems usually do not develop infections after inhaling Aspergillus spores. However, in individuals with compromised immune systems or underlying lung diseases, Aspergillus may grow in the lungs and cause infection. Structural lung issues, such as cavities, provide an ideal environment for Aspergillus growth. A weakened immune system cannot prevent the proliferation of spores and hyphae. Aspergillus hyphae can invade blood vessels and spread to other organs through the bloodstream[1].

Who is at higher risk for pulmonary aspergillosis?

Generally, pulmonary aspergillosis is more common in individuals with underlying lung diseases (e.g., asthma, cystic fibrosis, chronic obstructive pulmonary disease, tuberculosis) or weakened immune systems.

Analyzing specific clinical syndromes:

• Patients with chronic pulmonary aspergillosis often have structural lung diseases, such as residual cavities, bullae, or lung scars. These abnormalities may result from tuberculosis, chronic obstructive pulmonary disease, allergic bronchopulmonary aspergillosis, prior lung surgery, sarcoidosis, bronchiectasis, previous pneumothorax, or COVID-19 infection. These conditions are risk factors for chronic pulmonary aspergillosis[5].
• Invasive aspergillosis typically occurs only in immunocompromised individuals, including those with neutropenia, bone marrow or organ transplants, or those taking high-dose steroids[4].
• Allergic bronchopulmonary aspergillosis almost exclusively affects patients with asthma or cystic fibrosis[6].

Is pulmonary aspergillosis contagious?

Pulmonary aspergillosis is not contagious.

Humans are primarily infected by inhaling large amounts of Aspergillus spore-laden dust. There are no reported cases of human-to-human transmission of Aspergillus.

DIAGNOSIS

How is pulmonary aspergillosis diagnosed? What tests might be needed?

The diagnostic approach for pulmonary aspergillosis depends on the suspected clinical syndrome. Since Aspergillus is often inhaled into the airways, its identification in respiratory specimens (e.g., sputum, bronchoalveolar lavage fluid) alone does not confirm a diagnosis of pulmonary aspergillosis and requires case-by-case evaluation.

For suspected chronic pulmonary aspergillosis, diagnosis requires compatible symptoms (e.g., cough, hemoptysis) lasting ≥3 months, characteristic imaging findings (e.g., aspergilloma, cavities), and positive serum Aspergillus IgG, after excluding other diseases [4].

For suspected invasive aspergillosis, a definitive diagnosis requires positive Aspergillus culture or histopathology showing tissue invasion by hyphae from biopsy samples. If biopsy is unavailable, serum biomarkers (galactomannan, β-D-glucan, PCR), fungal staining/culture of sputum or bronchoalveolar lavage (BAL) samples, BAL galactomannan, or PCR may support diagnosis. Combined with risk factors, clinical features, and imaging findings, hyphae detection in respiratory secretions can guide treatment [7].

Suspected allergic bronchopulmonary aspergillosis (ABPA) requires:

● Asthma or cystic fibrosis as prerequisites.
● Mandatory criteria: elevated serum IgE or positive Aspergillus skin test, plus elevated serum IgE.
● ≥2 of the following: positive Aspergillus precipitin antibodies/elevated Aspergillus-specific IgG, compatible imaging (central bronchiectasis, mucus plugs), or blood eosinophils >500/μL without glucocorticoid use [6].

Diagnostic tests may include:
● Blood tests: CBC (focus on WBC/eosinophils), serum IgE, Aspergillus antigens (galactomannan, β-D-glucan, PCR), antibody tests.
● Respiratory specimens (sputum/BAL): microscopy, fungal culture.
● CT: Typical findings include aspergilloma, cavities, "halo sign," or "air-crescent sign."
● MRI: If cerebral involvement is suspected.
● Bronchoscopy: Visual inspection and sample collection via a camera-equipped tube, used when other tests are inconclusive.
● ABPA may require additional tests (pulmonary function, skin testing).

TREATMENT

How to Treat Pulmonary Aspergillosis?

For patients with chronic pulmonary aspergillosis, treatment varies depending on symptom severity, immune function status, and the extent of Aspergillus infection. For those with chronic progression, treatment is often challenging. In most cases, the primary goal is to stabilize the condition and prevent hemoptysis.

● Patients with simple aspergilloma (no or minimal hemoptysis) and immunocompetent or mildly immunocompromised individuals with Aspergillus nodules may not require antifungal therapy but should undergo annual follow-up with chest CT scans.
● Patients with severely immunocompromised Aspergillus nodules, chronic cavitary pulmonary aspergillosis, chronic fibrosing pulmonary aspergillosis, or subacute invasive pulmonary aspergillosis require antifungal therapy. Oral treatment may suffice for stable cases, while severe cases necessitate intravenous therapy in a hospital. Treatment duration varies—ranging from 3 to 12 months, several years, or even lifelong.
● For patients with hemoptysis, worsening or frequent episodes may warrant bronchial artery embolization or surgical resection [9].
For invasive aspergillosis, early diagnosis and prompt antifungal treatment are crucial for optimal outcomes. Reducing immunosuppression or considering surgery may also be necessary.
● Hospitalization for intravenous antifungal therapy is typically recommended. Treatment duration depends on infection site, underlying conditions, need for immunosuppression, and response—ranging from 6–12 weeks to months or years.
● Patients on immunosuppressive drugs should be evaluated for dose reduction or discontinuation.
● Surgery may be required for complex cases (e.g., chronic necrosis) to remove infected or necrotic tissue, such as sinus or skin involvement [8].
For allergic bronchopulmonary aspergillosis (ABPA), treatment aims to control acute inflammation and prevent progressive lung damage:
● Acute or recurrent cases may require oral glucocorticoids (initial 14-day course, tapered over 3–6 months).
● If tapering fails or symptoms recur, antifungals (e.g., itraconazole, voriconazole) for 16 weeks may be added.
● Remission may require asthma medications (e.g., inhaled bronchodilators/corticosteroids).
● Biologics (e.g., omalizumab) can be considered for refractory cases.
● Regular monitoring and avoiding high Aspergillus exposure (e.g., gardening, construction sites) are advised [10].

DIET & LIFESTYLE

What should patients with pulmonary aspergillosis pay attention to in daily life?

Mainly the following points:

• Maintain hygiene and strengthen protection: Keep good hygiene habits, wash hands frequently with soap and water, and wear masks. Ensure indoor ventilation and try to avoid crowded public places. Patients with allergic bronchopulmonary aspergillosis should avoid exposure to allergen environments.
• Rest and diet: Eat regular meals with a balanced diet that provides sufficient calories, protein, and vitamins. Quit smoking and alcohol. Exercise regularly to improve physical fitness. Maintain a regular schedule and get adequate sleep. Stay warm and avoid catching cold.
• If symptoms such as hemoptysis, fever, or worsening cough occur, seek medical attention promptly and actively cooperate with the doctor's treatment.

PREVENTION

Can pulmonary aspergillosis be prevented? How to prevent it?

For high-risk groups, reasonable protective measures should be taken, such as wearing masks when cleaning rooms. Minimize fungal exposure in daily life by avoiding gardening, fertilizing, or visiting construction or renovation sites.

For individuals at high risk of invasive aspergillosis, doctors may prescribe preventive medication. However, due to potential side effects or the risk of fungal resistance, preventive treatment is usually not recommended unless the patient is at very high risk.

For the general population with normal immune function and no underlying lung diseases (e.g., asthma), Aspergillus spores typically pose no threat, and special prevention is unnecessary. However, wearing masks in damp or dusty environments helps protect the respiratory tract, reduce dust inhalation, and avoid exposure to Aspergillus and other potential pathogens.

Is pulmonary aspergillosis serious? Does it affect lifespan?

Non-invasive aspergillosis progresses slowly and is relatively mild.

Invasive aspergillosis is a severe infection, often affecting the lungs, and may spread to other organs (e.g., heart, brain, digestive system) via the bloodstream. The condition can deteriorate rapidly, with an extremely high mortality rate.