Almost all patients have clinically diagnosed asthma, and present with wheezing (usually episodic in nature), coughing, shortness of breath and exercise intolerance (especially in patients with cystic fibrosis). Moderate and severe cases have symptoms suggestive of bronchiectasis, in particular thick sputum production (often containing brown mucus plugs), as well as symptoms mirroring recurrent infection such as pleuritic chest pain and fever. Patients with asthma and symptoms of ongoing infection, who do not respond to antibiotic treatment, should be suspected of ABPA.

Patients with subacute HP gradually develop a productive cough, dyspnea, fatigue, anorexia, weight loss, and pleurisy. Symptoms are similar to the acute form of the disease, but are less severe and last longer. On chest radiographs, micronodular or reticular opacities are most prominent in mid-to-lower lung zones. Findings may be present in patients who have experienced repeated acute attacks.

The subacute, or intermittent, form produces more well-formed noncaseating granulomas, bronchiolitis with or without organizing pneumonia, and interstitial fibrosis.

Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterised by an exaggerated response of the immune system (a hypersensitivity response) to the fungus "Aspergillus" (most commonly "Aspergillus fumigatus"). It occurs most often in patients with asthma or cystic fibrosis. "Aspergillus" spores are ubiquitous in soil and are commonly found in the sputum of healthy individuals. "A. fumigatus" is responsible for a spectrum of lung diseases known as aspergilloses.

ABPA causes airway inflammation, leading to bronchiectasis—a condition marked by abnormal dilation of the airways. Left untreated, the immune system and fungal spores can damage sensitive lung tissues and lead to scarring.

The exact criteria for the diagnosis of ABPA are not agreed upon. Chest X-rays and CT scans, raised blood levels of IgE and eosinophils, immunological tests for "Aspergillus" together with sputum staining and sputum cultures can be useful. Treatment consists of corticosteroids and antifungal medications.

In the acute form of HP, symptoms may develop 4–6 hours following heavy exposure to the provoking antigen. Symptoms include fever, chills, malaise, cough, chest tightness, dyspnea, rash, swelling and headache. Symptoms resolve within 12 hours to several days upon cessation of exposure.

Acute HP is characterized by poorly formed noncaseating interstitial granulomas and mononuclear cell infiltration in a peribronchial distribution with prominent giant cells.

On chest radiographs, a diffuse micronodular interstitial pattern (at times with ground-glass density in the lower and middle lung zones) may be observed. Findings are normal in approximately 10% of patients." In high-resolution CT scans, ground-glass opacities or diffusely increased radiodensities are present. Pulmonary function tests show reduced diffusion capacity of lungs for carbon monoxide (DLCO). Many patients have hypoxemia at rest, and all patients desaturate with exercise. Extrinsic allergic alveolitis may eventually lead to Interstitial lung disease.

Aspergillosis is an infection caused by the fungus "Aspergillus". Aspergillosis describes a large number of diseases involving both infection and growth of fungus as well as allergic responses. Aspergillosis can occur in a variety of organs, both in humans and animals.

The most common sites of infection are the respiratory apparatus (lungs, sinuses) and these infections can be:

- Invasive (e.g. – IPA)

- Non-invasive (e.g. Allergic Pulmonary Aspergillosis - ABPA)

- Chronic pulmonary and aspergilloma (e.g. chronic cavitary, semi-invasive)

- Severe asthma with fungal sensitisation (SAFS)

Chronic pulmonary aspergillosis (CPA) is a long-term aspergillus infection of the lung and "Aspergillus fumigatus" is almost always the species responsible for this illness. Patients fall into several groups as listed below.

- Those with an aspergilloma which is a ball of fungus found in a single lung cavity - which may improve or disappear, or change very little over a few years.

- Aspergillus nodule

- Chronic cavitary pulmonary aspergillosis (CCPA) where cavities are present in the lungs, but not necessarily with a fungal ball (aspergilloma).

- Chronic fibrosing pulmonary aspergillosis this may develop where pulmonary aspergillosis remains untreated and chronic scarring of the lungs occurs. Unfortunately scarring of the lungs does not improve.

Most patients with CPA have or have had an underlying lung disease. The most common diseases include tuberculosis, atypical mycobacterium infection, stage III fibrocystic pulmonary sarcoidosis, ABPA, lung cancer, COPD and emphysema, asthma and silicosis.

The specific criteria for diagnosis of CPA are:

Chest X-rays showing one or more lung cavities. There may be a fungal ball present or not.

Symptoms lasting more than 3 months, usually including weight loss, fatigue, cough, coughing blood (haemoptysis) and breathlessness

A blood test or tissue fluid test positive for Aspergillus species

Aspergilloma

An aspergilloma is a fungal mass caused by a fungal infection with Aspergillus species that grows in either scarred lungs or in a pre-existing lung cavity, which may have been caused by a previous infection. Patients with a previous history of tuberculosis, sarcoidosis, cystic fibrosis or other lung disease are most susceptible to an aspergilloma. Aspergillomas may have no specific symptoms but in many patients there is some coughing up of blood called haemoptysis - this may be infrequent and in small quantity, but can be severe and then it requires urgent medical help.

Tests used to diagnose an aspergilloma may include:

- Chest X-ray

- Chest CT

- Sputum culture

- Bronchoscopy or bronchoscopy with lavage (BAL)

- Serum precipitins for aspergillus (blood test to detect antibodies to aspergillus)

Almost all aspergillomas are caused by "Aspergillus fumigatus". In diabetic patients it may be caused by "Aspergillus niger". It is very rarely caused by "Aspergillus flavus", "Aspergillus oryzae", "Aspergillus terreus" or "Aspergillus nidulans".

A fungus ball in the lungs may cause no symptoms and may be discovered only with a chest X-ray, or it may cause repeated coughing up of blood, chest pain, and occasionally severe, even fatal, bleeding. A rapidly invasive "Aspergillus" infection in the lungs often causes cough, fever, chest pain, and difficulty breathing.

Poorly controlled aspergillosis can disseminate through the blood stream to cause widespread organ damage. Symptoms include fever, chills, shock, delirium, seizures and blood clots. The person may develop kidney failure, liver failure (causing jaundice), and breathing difficulties. Death can occur quickly.

Aspergillosis of the ear canal causes itching and occasionally pain. Fluid draining overnight from the ear may leave a stain on the pillow. Aspergillosis of the sinuses causes a feeling of congestion and sometimes pain or discharge. It can extend beyond the sinuses.

In addition to the symptoms, an X-ray or computerised tomography (CT) scan of the infected area provides clues for making the diagnosis. Whenever possible, a doctor sends a sample of infected material to a laboratory to confirm identification of the fungus.

Aspergillosis is the name given to a wide variety of diseases caused by infection by fungi of the genus "Aspergillus". The majority of cases occur in people with underlying illnesses such as tuberculosis or chronic obstructive pulmonary disease (COPD), but with otherwise healthy immune systems. Most commonly, aspergillosis occurs in the form of chronic pulmonary aspergillosis (CPA), aspergilloma or allergic bronchopulmonary aspergillosis (ABPA). Some forms are intertwined; for example ABPA and simple aspergilloma can progress to CPA.

Other, non-invasive manifestations include fungal sinusitis (both allergic in nature and with established fungal balls), otomycosis (ear infection), keratitis (eye infection) and onychomycosis (nail infection). In most instances these are less severe, and curable with effective antifungal treatment.

People with deficient immune systems—such as patients undergoing hematopoietic stem cell transplantation, chemotherapy for leukaemia, or AIDS—are at risk of more disseminated disease. Acute invasive aspergillosis occurs when the immune system fails to prevent "Aspergillus" spores from entering the bloodstream via the lungs. Without the body mounting an effective immune response, fungal cells are free to disseminate throughout the body and can infect major organs such as the heart and kidneys.

The most frequently identified pathogen is "Aspergillus fumigatus"—a ubiquitous organism that is capable of living under extensive environmental stress. It is estimated that most humans inhale thousands of "Aspergillus" spores daily, but they do not affect most people’s health due to effective immune responses. Taken together, the major chronic, invasive and allergic forms of aspergillosis account for around 600,000 deaths annually worldwide.