Flavorings-related lung disease can be prevented with the use of engineering controls (e.g. exhaust hoods or closed systems), personal protective equipment, monitoring of potentially affected workers, worker education, and by not using lung-disease-causing flavorings.

The diagnosis is typically made by clinical examination. Chest X-ray is sometimes useful to exclude bacterial pneumonia, but not indicated in routine cases.

Testing for the specific viral cause can be done but has little effect on management and thus is not routinely recommended. RSV testing by direct immunofluorescence testing on nasopharyngeal aspirate had a sensitivity of 61% and specificity of 89%. Identification of those who are RSV-positive can help for: disease surveillance, grouping ("cohorting") people together in hospital wards to prevent cross infection, predicting whether the disease course has peaked yet, reducing the need for other diagnostic procedures (by providing confidence that a cause has been identified).

Infants with bronchiolitis between the age of two and three months have a second infection by bacteria (usually a urinary tract infection) less than 6% of the time. Preliminary studies have suggested that elevated procalcitonin levels may assist clinicians in determining the presence of bacterial coinfection, which could prevent unnecessary antibiotic use and costs.

Bronchiolitis obliterans is often misdiagnosed as asthma, chronic bronchitis, emphysema or pneumonia.

Several tests are often needed to correctly diagnose bronchiolitis obliterans, including chest X-rays, diffusing capacity of the lung tests (DLCO), spirometry, lung volume tests, high-resolution CT (HRCT), and lung biopsy. Diffusing capacity of the lung (DLCO) tests are usually normal; people with early-stage BO are more likely to have normal DLCO. Spirometry tests usually show fixed airway obstructions and sometimes restriction, where the lungs can't expand fully. Lung volume tests may show hyperinflation (excessive air in lungs caused by air trapping). HRCT can also show air trapping when the person being scanned breathes out completely; it can also show thickening in the airway and haziness in the lungs. Transthoracic lung biopsies are preferable for diagnosis of constrictive BO compared to transbronchial biopsies; regardless of the type of biopsy, a diagnosis may only be achieved by examination of multiple samples.

The chest x-ray is distinctive with features that appear similar to an extensive pneumonia, with both lungs showing widespread white patches. The white patches may seem to migrate from one area of the lung to another as the disease persists or progresses. Computed tomography (CT) may be used to confirm the diagnosis. Often the findings are typical enough to allow the doctor to make a diagnosis without ordering additional tests. To confirm the diagnosis, a doctor may perform a lung biopsy using a bronchoscope. Many times, a larger specimen is needed and must be removed surgically.

Plain chest radiography shows normal lung volumes, with characteristic patchy unilateral or bilateral consolidation. Small nodular opacities occur in up to 50% of patients and large nodules in 15%. On high resolution computed tomography, airspace consolidation with air bronchograms is present in more than 90% of patients, often with a lower zone predominance A subpleural or peribronchiolar distribution is noted in up to 50% of patients. Ground glass appearance or hazy opacities associated with the consolidation are detected in most patients.

Pulmonary physiology is restrictive with a reduced diffusion capacity of the lung for carbon monoxide (DCO). Airflow limitation is uncommon; gas exchange is usually abnormal and mild hypoxemia is common. Bronchoscopy with bronchoalveolar lavage reveals up to 40% lymphocytes, along with more subtle increases in neutrophils and eosinophils. In patients with typical clinical and radiographic features, a transbronchial biopsy that shows the pathologic pattern of organizing pneumonia and lacks features of an alternative diagnosis is adequate to make a tentative diagnosis and start therapy. On surgical lung biopsy, the histopathologic pattern is organizing pneumonia with preserved lung architecture; this pattern is not exclusive to BOOP and must be interpreted in the clinical context.

Histologically, cryptogenic organizing pneumonia is characterized by the presence of polypoid plugs of loose organizing connective tissue (Masson bodies) within alveolar ducts, alveoli, and bronchioles.

Rare cases of BOOP have induced with lobar cicatricial atelectasis.

A CT scan of the lungs and histopathology along with a history of working in the flocking industry can diagnose flock worker's lung. A differential diagnosis may also include Sjögren's syndrome and lymphoid interstitial pneumonia. Flock worker's lung may be misdiagnosed as asthma or recurrent pneumonia. Though X-rays may be abnormal, CT scans are more useful as a diagnostic tool in flock worker's lung. Other diagnostic methods may include a transbronchial biopsy or wedge biopsy.

Prevention of bronchiolitis relies strongly on measures to reduce the spread of the viruses that cause respiratory infections (that is, handwashing, and avoiding exposure to those symptomatic with respiratory infections). In addition to good hygiene an improved immune system is a great tool for prevention. One way to improve the immune system is to feed the infant with breast milk, especially during the first month of life. Immunizations are available for premature infants who meet certain criteria (some cardiac and respiratory disorders) such as Palivizumab (a monoclonal antibody against RSV). Passive immunization therapy requires monthly injections during winter.

The diagnosis is based upon a history of symptoms after exposure to the allergen and clinical tests. A physician may take blood tests, seeking signs of inflammation, a chest X-ray and lung function tests. The sufferer shows a restrictive loss of lung function.

Precipitating IgG antibodies against fungal or avian antigens can be detected in the laboratory using the traditional Ouchterlony immunodiffusion method wherein 'precipitin' lines form on agar plate. The ImmunoCAP technology has replaced this time consuming, labor-intensive method with their automated CAP assays and FEIA (Fluorescence enzyme immunoassay) that can detect IgG antibodies against Aspergillus fumigatus (Farmer's lung or for ABPA) or avian antigens (Bird Fancier's Lung).

Although overlapping in many cases, hypersensitivity pneumonitis may be distinguished from occupational asthma in that it is not restricted to only occupational exposure, and that asthma generally is classified as a type I hypersensitivity. Unlike asthma, hypersensitivity pneumonitis targets lung alveoli rather than bronchi.

Investigation is tailored towards the symptoms and signs. A proper and detailed history looking for the occupational exposures, and for signs of conditions listed above is the first and probably the most important part of the workup in patients with interstitial lung disease. Pulmonary function tests usually show a restrictive defect with decreased diffusion capacity (DLCO).

A lung biopsy is required if the clinical history and imaging are not clearly suggestive of a specific diagnosis or malignancy cannot otherwise be ruled out. In cases where a lung biopsy is indicated, a trans-bronchial biopsy is usually unhelpful, and a surgical lung biopsy is often required.

A number of methods can determine how much COPD is affecting a given individual. The modified British Medical Research Council questionnaire or the COPD assessment test (CAT) are simple questionnaires that may be used to determine the severity of symptoms. Scores on CAT range from 0–40 with the higher the score, the more severe the disease. Spirometry may help to determine the severity of airflow limitation. This is typically based on the FEV expressed as a percentage of the predicted "normal" for the person's age, gender, height, and weight. Both the American and European guidelines recommended partly basing treatment recommendations on the FEV. The GOLD guidelines suggest dividing people into four categories based on symptoms assessment and airflow limitation. Weight loss and muscle weakness, as well as the presence of other diseases, should also be taken into account.

Chest radiography is usually the first test to detect interstitial lung diseases, but the chest radiograph can be normal in up to 10% of patients, especially early on the disease process.

High resolution CT of the chest is the preferred modality, and differs from routine CT of the chest. Conventional (regular) CT chest examines 7–10 mm slices obtained

at 10 mm intervals; high resolution CT examines 1-1.5 mm slices at 10 mm

intervals using a high spatial frequency reconstruction algorithm. The HRCT therefore provides approximately 10 times more resolution than the conventional CT chest, allowing the HRCT to elicit details that cannot otherwise be visualized.

Radiologic appearance alone however is not adequate and should be interpreted in the clinical context, keeping in mind the temporal profile of the disease process.

Interstitial lung diseases can be classified according to radiologic patterns.

A chest X-ray and complete blood count may be useful to exclude other conditions at the time of diagnosis. Characteristic signs on X-ray are overexpanded lungs, a flattened diaphragm, increased retrosternal airspace, and bullae, while it can help exclude other lung diseases, such as pneumonia, pulmonary edema, or a pneumothorax. A high-resolution computed tomography scan of the chest may show the distribution of emphysema throughout the lungs and can also be useful to exclude other lung diseases. Unless surgery is planned, however, this rarely affects management. An analysis of arterial blood is used to determine the need for oxygen; this is recommended in those with an FEV less than 35% predicted, those with a peripheral oxygen saturation less than 92%, and those with symptoms of congestive heart failure. In areas of the world where alpha-1 antitrypsin deficiency is common, people with COPD (particularly those below the age of 45 and with emphysema affecting the lower parts of the lungs) should be considered for testing.

Flock worker's lung can be prevented with engineering controls that protect workers from inhaling flock. Engineering controls to prevent inhalation of flock can include using guillotine cutters rather than rotary cutters, and ensuring that blades are sharp, since dull blades shear off more respirable particles. Flocking plants have also implemented medical surveillance programs for workers to diagnose cases at an earlier stage. Another technique for preventing flock worker's lung is cleaning the workplace with alternatives to compressed air in order to avoid resuspending particulates in the air.

Bronchoalveolar lavage (BAL) is a well-tolerated diagnostic procedure in ILD. BAL cytology analyses (differential cell counts) should be considered in the evaluation of patients with IPF at the discretion of the treating physician based on availability and experience at their institution. BAL may reveal alternative specific diagnoses: malignancy, infections, eosinophilic pneumonia, histiocytosis X, or alveolar proteinosis. In the evaluation of patients with suspected IPF, the most important application of BAL is in the exclusion of other diagnoses. Prominent lymphocytosis (>30%) generally allows excluding a diagnosis of IPF.

Diagnosis is typically based on a person's signs and symptoms. The color of the sputum does not indicate if the infection is viral or bacterial. Determining the underlying organism is typically not needed. Other causes of similar symptoms include asthma, pneumonia, bronchiolitis, bronchiectasis, and COPD. A chest X-ray may be useful to detect pneumonia.

Another common sign of bronchitis is a cough which lasts ten days to three weeks. If the cough lasts a month or a year it may be chronic bronchitis. In addition to having a cough a fever may be present. Acute bronchitis is normally caused by a viral infection. Typically these infections are rhinovirus, para influenza, or influenza. No specific testing is normally needed to diagnose acute bronchitis.

The following are precautionary measures that can be taken to avoid the spread of bagassosis:

1. Dust control-prevention /suppression of dust such as wet process, enclosed apparatus, exhaust ventilation etc. should be used

2. Personal protection- masks/ respirators

3. Medical control- initial medical examination & periodical checkups of workers

4. Bagasse control- keep moisture content above 20% and spray bagasse with 2% propionic acid

Lung biopsies can be diagnostic in cases of chronic hypersensitivity pneumonitis, or may help to suggest the diagnosis and trigger or intensify the search for an allergen. The main feature of chronic hypersensitivity pneumonitis on lung biopsies is expansion of the interstitium by lymphocytes accompanied by an occasional multinucleated giant cell or loose granuloma.

When fibrosis develops in chronic hypersensitivity pneumonitis, the differential diagnosis in lung biopsies includes the idiopathic interstitial pneumonias. This group of diseases includes usual interstitial pneumonia, non-specific interstitial pneumonia and cryptogenic organizing pneumonia, among others.

The prognosis of some idiopathic interstitial pneumonias, e.g. idiopathic usual interstitial pneumonia (i.e. idiopathic pulmonary fibrosis), are very poor and the treatments of little help. This contrasts the prognosis (and treatment) for hypersensitivity pneumonitis, which is generally fairly good if the allergen is identified and exposures to it significantly reduced or eliminated. Thus, a lung biopsy, in some cases, may make a decisive difference.

According to the updated 2011 guidelines, in the absence of a typical UIP pattern on HRCT, a surgical lung biopsy is required for confident diagnosis.

Histologic specimens for the diagnosis of IPF must be taken at least in three different places and be large enough that the pathologist can comment on the underlying lung architecture. Small biopsies, such as those obtained via transbronchial lung biopsy (performed during bronchoscopy) are usually not sufficient for this purpose. Hence, larger biopsies obtained surgically via a thoracotomy or thoracoscopy are usually necessary.

Lung tissue from people with IPF usually show a characteristic histopathologic UIP pattern and is therefore the pathologic counterpart of IPF. Although a pathologic diagnosis of UIP often corresponds to a clinical diagnosis of IPF, a UIP histologic pattern can be seen in other diseases as well, and fibrosis of known origin (rheumatic diseases for example). There are four key features of UIP including interstitial fibrosis in a ‘patchwork pattern’, interstitial scarring, honeycomb changes and fibroblast foci.

Fibroblastic foci are dense collections of myofibroblasts and scar tissue and, together with honeycombing, are the main pathological findings that allow a diagnosis of UIP.

Physical examination may sometimes reveal low blood pressure, high heart rate, or low oxygen saturation. The respiratory rate may be faster than normal, and this may occur a day or two before other signs. Examination of the chest may be normal, but it may show decreased chest expansion on the affected side. Harsh breath sounds from the larger airways that are transmitted through the inflamed lung are termed bronchial breathing and are heard on auscultation with a stethoscope. Crackles (rales) may be heard over the affected area during inspiration. Percussion may be dulled over the affected lung, and increased, rather than decreased, vocal resonance distinguishes pneumonia from a pleural effusion.

Pneumonia is typically diagnosed based on a combination of physical signs and a chest X-ray. However, the underlying cause can be difficult to confirm, as there is no definitive test able to distinguish between bacterial and non-bacterial origin.

The World Health Organization has defined pneumonia in children clinically based on either a cough or difficulty breathing and a rapid respiratory rate, chest indrawing, or a decreased level of consciousness. A rapid respiratory rate is defined as greater than 60 breaths per minute in children under 2 months old, greater than 50 breaths per minute in children 2 months to 1 year old, or greater than 40 breaths per minute in children 1 to 5 years old. In children, low oxygen levels and lower chest indrawing are more sensitive than hearing chest crackles with a stethoscope or increased respiratory rate. Grunting and nasal flaring may be other useful signs in children less than five years old.

In general, in adults, investigations are not needed in mild cases. There is a very low risk of pneumonia if all vital signs and auscultation are normal. In persons requiring hospitalization, pulse oximetry, chest radiography and blood tests—including a complete blood count, serum electrolytes, C-reactive protein level, and possibly liver function tests—are recommended. Procalcitonin may help determine the cause and support who should receive antibiotics.

The diagnosis of influenza-like illness can be made based on the signs and symptoms; however, confirmation of an influenza infection requires testing. Thus, treatment is frequently based on the presence of influenza in the community or a rapid influenza test.

Prevention is by not smoking and avoiding other lung irritants. Frequent hand washing may also be protective. Treatment of acute bronchitis typically involves rest, paracetamol (acetaminophen), and NSAIDs to help with the fever. Cough medicine has little support for its use and is not recommended in children less than six years of age. There is tentative evidence that salbutamol may be useful in those with wheezing; however, it may result in nervousness and tremors. Antibiotics should generally not be used. An exception is when acute bronchitis is due to pertussis. Tentative evidence supports honey and pelargonium to help with symptoms. Getting plenty of rest and fluids is also often recommended.

In the differential diagnosis (finding the correct diagnosis between diseases that have overlapping features) of some obstructive lung diseases, DPB is often considered. A number of DPB symptoms resemble those found with other obstructive lung diseases such as asthma, chronic bronchitis, and emphysema. Wheezing, coughing with sputum production, and shortness of breath are common symptoms in such diseases, and obstructive respiratory functional impairment is found on pulmonary function testing. Cystic fibrosis, like DPB, causes severe lung inflammation, excess mucus production, and infection; but DPB does not cause disturbances of the pancreas nor the electrolytes, as does CF, so the two diseases are different and probably unrelated. DPB is distinguished by the presence of lesions that appear on X-rays as nodules in the bronchioles of both lungs; inflammation in all tissue layers of the respiratory bronchioles; and its higher prevalence among individuals with East Asian lineage.

DPB and bronchiolitis obliterans are two forms of primary bronchiolitis. Specific overlapping features of both diseases include strong cough with large amounts of often pus-filled sputum; nodules viewable on lung X-rays in the lower bronchi and bronchiolar area; and chronic sinusitis. In DPB, the nodules are more restricted to the respiratory bronchioles, while in OB they are often found in the membranous bronchioles (the initial non-cartilaginous section of the bronchiole, that divides from the tertiary bronchus) up to the secondary bronchus. OB is a bronchiolar disease with worldwide prevalence, while DPB has more localized prevalence, predominantly in Japan. Prior to clinical recognition of DPB in recent years, it was often misdiagnosed as bronchiectasia, COPD, IPF, phthisis miliaris, sarcoidosis or alveolar cell carcinoma.

The exact cause of rheumatoid lung disease is unknown. However, associated factors could be due largely to smoking. Sometimes, the medicines used to treat rheumatoid arthritis, especially methotrexate, may result in lung disease.

Prevention's:

- Stop smoking: Chemicals found in cigarettes can irritate already delicate lung tissue, leading to further complications.

- Having regular checkups: The doctor could listen to lungs and monitor breathing, because lung problems that are detected early can be easier to treat.

According to a recent study, the main risk factors for RA-ILD are advancing age, male sex, greater RA disease activity, rheumatoid factor (RF) positivity, and elevated titers of anticitrullinated protein antibodies such as anticyclic citrullinated peptide. Cigarette smoking also appears to increase risk of RA-ILD, especially in patients with human leukocyte antigen DRB1.

A recently published retrospective study by a team from Beijing Chao-Yang Hospital in Beijing, China, supported three of the risk factors listed for RA-ILD and identified an additional risk factor. In that study of 550 RA patients, logistic regression analysis of data collected on the 237 (43%) with ILD revealed that age, smoking, RF positivity, and elevated lactate dehydrogenase closely correlated with ILD.

Recent studies have identified risk factors for disease progression and mortality. A retrospective study of 167 patients with RA-ILD determined that the usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography (HRCT) was a risk factor for progression, as were severe disease upon diagnosis and rate of change in pulmonary function test results in the first 6 months after diagnosis.

A study of 59 RA-ILD patients found no median survival difference between those with the UIP pattern and those without it. But the UIP group had more deaths, hospital admissions, need for supplemental oxygen, and decline in lung function.

The diagnosis of DPB requires analysis of the lungs and bronchiolar tissues, which can require a lung biopsy, or the more preferred high resolution computed tomography (HRCT) scan of the lungs. The diagnostic criteria include severe inflammation in all layers of the respiratory bronchioles and lung tissue lesions that appear as nodules within the terminal and respiratory bronchioles in both lungs. The nodules in DPB appear as opaque lumps when viewed on X-rays of the lung, and can cause airway obstruction, which is evaluated by a pulmonary function test, or PFT. Lung X-rays can also reveal dilation of the bronchiolar passages, another sign of DBP. HRCT scans often show blockages of some bronchiolar passages with mucus, which is referred to as the "tree-in-bud" pattern. Hypoxemia, another sign of breathing difficulty, is revealed by measuring the oxygen and carbon dioxide content of the blood, using a blood test called arterial blood gas. Other findings observed with DPB include the proliferation of lymphocytes (white blood cells that fight infection), neutrophils, and foamy histiocytes (tissue macrophages) in the lung lining. Bacteria such as "H. influenzae" and "P. aeruginosa" are also detectable, with the latter becoming more prominent as the disease progresses. The white blood, bacterial and other cellular content of the blood can be measured by taking a complete blood count (CBC). Elevated levels of IgG and IgA (classes of immunoglobulins) may be seen, as well as the presence of rheumatoid factor (an indicator of autoimmunity). Hemagglutination, a clumping of red blood cells in response to the presence of antibodies in the blood, may also occur. Neutrophils, beta-defensins, leukotrienes, and chemokines can also be detected in bronchoalveolar lavage fluid injected then removed from the bronchiolar airways of individuals with DPB, for evaluation.