Initially, the disease appears as alveolitis, and then progresses to emphysema.

Patients may develop pneumothorax (collapsed lung).

The term "bronchiolitis" generally refers to inflammation of the bronchioles. DPB is classified as a form of "primary bronchiolitis", which means that the underlying cause of bronchiolitis is originating from or is confined to the bronchioles. Along with DPB, additional forms of primary bronchiolitis include bronchiolitis obliterans, follicular bronchiolitis, respiratory bronchiolitis, mineral dust airway disease, and a number of others. Unlike DPB, bronchiolitis that is not considered "primary" would be associated with diseases of the larger airways, such as chronic bronchitis.

Symptoms of DPB include chronic sinusitis (inflamed paranasal sinuses), wheezing, crackles (respiratory sounds made by obstructions such as phlegm and secretions in the lungs), dyspnea (shortness of breath), and a severe cough that yields large amounts of sputum (coughed-up phlegm). There may be pus in the sputum, and affected individuals may have fever. Typical signs of DPB progression include (enlargement) of the bronchiolar passages and hypoxemia (low levels of oxygen in the blood). If DPB is left untreated, bronchiectasis will occur; it is characterized by dilation and thickening of the walls of the bronchioles, inflammatory damage to respiratory and terminal bronchioles, and pooling of mucus in the lungs. DPB is associated with progressive respiratory failure, hypercapnia (increased levels of carbon dioxide in the blood), and can eventually lead to pulmonary hypertension (high blood pressure in the pulmonary vein and artery) and cor pulmonale (dilation of the right ventricle of the heart, or "right heart failure").

The typical symptoms of UIP are progressive shortness of breath and cough for a period of months. In some patients, UIP is diagnosed only when a more acute disease supervenes and brings the patient to medical attention.

The cause of the scarring in UIP may be known (less commonly) or unknown (more commonly). Since the medical term for conditions of unknown cause is "idiopathic", the clinical term for UIP of unknown cause is idiopathic pulmonary fibrosis (IPF). Examples of known causes of UIP include systemic sclerosis/scleroderma, rheumatoid arthritis, asbestosis, and prolonged use of medications such as nitrofurantoin or amiodarone.

Lycoperdonosis is a respiratory disease caused by the inhalation of large amounts of spores from mature puffballs. It is classified as a hypersensitivity pneumonitis (also called extrinsic allergic alveolitis)—an inflammation of the alveoli within the lung caused by hypersensitivity to inhaled natural dusts. It is one of several types of hypersensitivity pneumonitis caused by different agents that have similar clinical features. Typical progression of the disease includes symptoms of a cold hours after spore inhalation, followed by nausea, rapid pulse, crepitant rales (a sound like that made by rubbing hairs between the fingers, heard at the end of inhalation), and dyspnea. Chest radiographs reveal the presence of nodules in the lungs. The early symptoms presented in combination with pulmonary abnormalities apparent on chest radiographs may lead to misdiagnosis of the disease as tuberculosis, histiocytosis, or pneumonia caused by "Pneumocystis carinii". Lycoperdonosis is generally treated with corticosteroids, which decrease the inflammatory response; these are sometimes given in conjunction with antimicrobials.

The disease was first described in the medical literature in 1967 by R.D. Strand and colleagues in the "New England Journal of Medicine". In 1976, a 4-year-old was reported developing the disease in Norway after purposely inhaling a large quantity of "Lycoperdon" spores to stop a nosebleed. "Lycoperdon" species are sometimes used in folk medicine in the belief that their spores have haemostatic properties. A 1997 case report discussed several instances of teenagers inhaling the spores. In one severe case, the individual inhaled enough spores so as to be able to blow them out of his mouth. He underwent bronchoscopy and then had to be on life support before recovering in about four weeks. In another instance, a teenager spent 18 days in a coma, had portions of his lung removed, and suffered severe liver damage. In Wisconsin, eight teenagers who inhaled spores at a party presented clinical symptoms such as cough, fever, shortness of breath, myalgia, and fatigue within a week. Five of the eight required hospitalization; of these, two required intubation to assist in breathing. The disease is rare, possibly because of the large quantity of spores that need to be inhaled for clinical effects to occur. Lycoperdonosis also occurs in dogs; in the few reported cases, the animals had been playing or digging in areas known to contain puffballs. Known species of puffballs implicated in the etiology of the published cases include the widespread "Lycoperdon perlatum" (the "devil's snuff-box", "L. gemmatum") and "Calvatia gigantea", both of the Lycoperdaceae family.

Bauxite pneumoconiosis, also known as Shaver's disease, corundum smelter's lung, bauxite lung or bauxite smelters' disease, is a progressive form of pneumoconiosis usually caused by occupational exposure to bauxite fumes which contain aluminium and silica particulates.

It is typically seen in workers involved in the smelting of bauxite to produce corundum.

Positive indications on patient assessment:

- Shortness of breath

- Chest X-ray may show a characteristic patchy, subpleural, bibasilar interstitial infiltrates or small cystic radiolucencies called honeycombing.

Pneumoconiosis in combination with multiple pulmonary rheumatoid nodules in rheumatoid arthritis patients is known as Caplan's syndrome.

Pneumoconiosis is an occupational lung disease and a restrictive lung disease caused by the inhalation of dust, often in mines and from agriculture.

In 2013, it resulted in 260,000 deaths, up from 251,000 deaths in 1990. Of these deaths, 46,000 were due to silicosis, 24,000 due to asbestosis and 25,000 due to coal workers pneumoconiosis.

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.

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.

Acute inhalation injury may result from frequent and widespread use of household cleaning agents and industrial gases (including chlorine and ammonia). The airways and lungs receive continuous first-pass exposure to non-toxic and irritant or toxic gases via inhalation. Irritant gases are those that, on inhalation, dissolve in the water of the respiratory tract mucosa and provoke an inflammatory response, usually from the release of acidic or alkaline radicals. Smoke, chlorine, phosgene, sulfur dioxide, hydrogen chloride, hydrogen sulfide, nitrogen dioxide, ozone, and ammonia are common irritants.

Depending on the type and amount of irritant gas inhaled, victims can experience symptoms ranging from minor respiratory discomfort to acute airway and lung injury and even death. A common response cascade to a variety of irritant gases includes inflammation, edema and epithelial sloughing, which if left untreated can result in scar formation and pulmonary and airway remodeling. Currently, mechanical ventilation remains the therapeutic mainstay for pulmonary dysfunction following acute inhalation injury.

Clinically, the most serious and immediate complication is acute respiratory distress syndrome (ARDS), which usually occurs within 24 h. Those with significant lower airway involvement may develop bacterial infection. Importantly, victims suffering body surface burn and smoke inhalation are the most susceptible. Thermal injury combined with inhalation injury compromises pulmonary function, producing microvascular hyperpermeability that leads to a significant increase in lung lymph flow and pulmonary edema. The terrorist attack on the World Trade Center on September 11, 2001 left many people with impaired lung function. A study of firefighters and EMS workers enrolled in the FDNY WTC Medical Monitoring and Treatment Program, whose lung function was tested prior to 9/11, documented a steep decline in lung function in the first year after 9/11. A new study that includes a thousand additional workers shows that the declines have persisted over time. Prior to 9/11, 3% of firefighters had below-normal lung function, one year after 9/11 nearly 19% did, and six years later it stabilized at 13%. Ten to 14 days after acute exposure to some agents (e.g. ammonia, nitrogen oxides, sulfur dioxide, mercury), some patients develop bronchiolitis obliterans progressing to ARDS. Bronchiolitis obliterans with organized pneumonia can ensue when granulation tissue accumulates in the terminal airways and alveolar ducts during the body's reparative process. A minority of these patients develop late pulmonary fibrosis. Also at enhanced risk are persons with co-morbidities. Several studies report that both aged persons and smokers are especially vulnerable to the adverse effects of inhalation injury.

Symptoms arise 4–12 hours after exposure to an organic dust, and generally last from one to five days. Common generalised symptoms include fever over 38 °C, chills, myalgia and malaise. The most frequent respiratory symptoms are dyspnea and a dry cough, while a wheeze may be present less commonly. Headache, rhinitis, conjunctivitis and keratitis can also be present, and skin irritation may occur in those handling grain.

Respiratory function may worsen to the point where hypoxia occurs, and damage to the airways may lead to non-cardiogenic pulmonary edema one to three days post exposure.

Laboratory investigations may show a raised white cell (and specifically neutrophil) count, while a chest X-ray is often normal or shows minimal interstitial infiltration.

Aspiration pneumonia is often caused by a defective swallowing mechanism, often due to a neurological disease or as the result of an injury that directly impairs swallowing or interferes with consciousness. Examples of the former are stroke, Parkinson's disease, and multiple sclerosis, and examples of the latter are some types of dementia, seizures, intoxication, and general anaesthesia. For many types of surgical operations, patients are therefore instructed to take nothing by mouth (nil per os, abbreviated as NPO) for at least four hours before surgery.

The location is often gravity dependent, and depends on the patient position. Generally, the right middle and lower lung lobes are the most common sites affected, due to the larger caliber and more vertical orientation of the right mainstem bronchus. Patients who aspirate while standing can have bilateral lower lung lobe infiltrates. The right upper lobe is a common area of consolidation in alcoholics who aspirate in the prone position.

Organic dust toxic syndrome (ODTS) is a potentially severe flu-like syndrome originally described in farmers, mushroom workers, bird breeders and other persons occupationally exposed to dusty conditions.

Bilateral hilar lymphadenopathy is a bilateral enlargement of the lymph nodes of pulmonary hila. It is a radiographic term that describes the enlargement of mediastinal lymph nodes and is most commonly identified by a chest x-ray.

The following are causes of BHL:

- Sarcoidosis

- Infection

- Tuberculosis

- Fungal infection

- Mycoplasma

- Intestinal Lipodystrophy (Whipple's disease)

- Malignancy

- Lymphoma

- Carcinoma

- Mediastinal tumors

- Inorganic dust disease

- Silicosis

- Berylliosis

- Extrinsic allergic alveolitis

- Such as bird fancier's lung

- Less common causes also exist:

- Eosinophilic granulomatosis with polyangiitis

- Human immunodeficiency virus

- Extrinsic allergic alveolitis

- Adult-onset Still's disease

Mold health issues are potentially harmful effects of molds.

Molds (US usage; British English "moulds") are ubiquitous in the biosphere, and mold spores are a common component of household and workplace dust. The United States Centers for Disease Control and Prevention reported in its June 2006 report, 'Mold Prevention Strategies and Possible Health Effects in the Aftermath of Hurricanes and Major Floods,' that "excessive exposure to mold-contaminated materials can cause adverse health effects in susceptible persons regardless of the type of mold or the extent of contamination." When mold spores are present in abnormally high quantities, they can present especially hazardous health risks to humans after prolonged exposure, including allergic reactions or poisoning by mycotoxins, or causing fungal infection (mycosis).

Symptoms of mold exposure can include:

- Nasal and sinus congestion, runny nose

- Respiratory problems, such as wheezing and difficulty breathing, chest tightness

- Cough

- Throat irritation

- Sneezing / Sneezing fits

Cyanosis is defined as the bluish or purplish discolouration of the skin or mucous membranes due to the tissues near the skin surface having low oxygen saturation. Based on Lundsgaard and Van Slyke's work, it is classically described as occurring if 5.0 g/dL of deoxyhemoglobin or greater is present. This was based on an estimate of capillary saturation based on a mean of arterial versus peripheral venous blood gas measurements. Since estimation of hypoxia is usually now based either on arterial blood gas measurement or pulse oximetry, this is probably an overestimate, with evidence that levels of 2.0 g/dL of deoxyhemoglobin may reliably produce cyanosis. Since, however, the presence of cyanosis is dependent upon there being an absolute quantity of deoxyhemoglobin, the bluish color is more readily apparent in those with high hemoglobin counts than it is with those with anemia. Also, the bluer the color, the more difficult it is to detect on deeply pigmented skin. When signs of cyanosis first appear, such as on the lips or fingers, intervention should be made within 3–5 minutes because a severe hypoxia or severe circulatory failure may have induced the cyanosis.

The name "cyanosis" literally means "the blue disease" or "the blue condition". It is derived from the color cyan, which comes from κυανός, "kyanós", the Greek word for "blue".

Cyanosis is defined as a bluish discoloration, especially of the skin and mucous membranes, due to excessive concentration of deoxyhemoglobin in the blood caused by deoxygenation.

Cyanosis is divided into two main types: Central (around the core, lips, and tongue) and Peripheral (only the extremities or fingers).

Sick building syndrome (SBS) is a medical condition where people in a building suffer from symptoms of illness or feel unwell for no apparent reason. The symptoms tend to increase in severity with the time people spend in the building, and improve over time or even disappear when people are away from the building. The main identifying observation is an increased incidence of complaints of symptoms such as headache, eye, nose, and throat irritation, fatigue, and dizziness and nausea. These symptoms appear to be linked to time spent in a building, though no specific illness or cause can be identified. SBS is also used interchangeably with "building-related symptoms", which orients the name of the condition around patients rather than a "sick" building. A 1984 World Health Organization (WHO) report suggested up to 30% of new and remodeled buildings worldwide may be subject of complaints related to poor indoor air quality.

Sick building causes are frequently pinned down to flaws in the heating, ventilation, and air conditioning (HVAC) systems. However, there have been inconsistent findings on whether air conditioning systems result in SBS or not. Other causes have been attributed to contaminants produced by outgassing of some types of building materials, volatile organic compounds (VOC), molds (see mold health issues), improper exhaust ventilation of ozone (byproduct of some office machinery), light industrial chemicals used within, or lack of adequate fresh-air intake/air filtration (see Minimum efficiency reporting value).

A liver abscess is a pus-filled mass inside the liver. Common causes are abdominal conditions such as appendicitis or diverticulitis due to haematogenous spread through the portal vein.