Pulmonary fibrosis creates scar tissue. The scarring is permanent once it has developed. Slowing the progression and prevention depends on the underlying cause:

- Treatment options for idiopathic pulmonary fibrosis are very limited. Though research trials are ongoing, there is no evidence that any medications can significantly help this condition. Lung transplantation is the only therapeutic option available in severe cases. Since some types of lung fibrosis can respond to corticosteroids (such as prednisone) and/or other medications that suppress the body's immune system, these types of drugs are sometimes prescribed in an attempt to slow the processes that lead to fibrosis.

- Two pharmacological agents intended to prevent scarring in mild idiopathic fibrosis are pirfenidone, which reduced reductions in the 1-year rate of decline in FVC. Pirfenidone also reduced the decline in distances on the 6-minute walk test, but had no effect on respiratory symptoms. The second agent is nintedanib, which acts as antifibrotic, mediated through the inhibition of a variety of tyrosine kinase receptors (including platelet-derived growth factor, fibroblast growth factor, and vascular endothelial growth factor). A randomized clinical trial showed it reduced lung-function decline and acute exacerbations.

- Anti-inflammatory agents have only limited success in reducing the fibrotic progress. Some of the other types of fibrosis, such as non-specific interstitial pneumonia, may respond to immunosuppressive therapy such as corticosteroids. However, only a minority of patients respond to corticosteroids alone, so additional immunosuppressants, such as cyclophosphamide, azathioprine, methotrexate, penicillamine, and cyclosporine may be used. Colchicine has also been used with limited success. There are ongoing trials with newer drugs such as IFN-γ and mycophenolate mofetil..

- Hypersensitivity pneumonitis, a less severe form of pulmonary fibrosis, is prevented from becoming aggravated by avoiding contact with the causative material.

- Oxygen supplementation improves the quality of life and exercise capacity. Lung transplantation may be considered for some patients.

Hypoxia caused by pulmonary fibrosis can lead to pulmonary hypertension, which, in turn, can lead to heart failure of the right ventricle. Hypoxia can be prevented with oxygen supplementation.

Pulmonary fibrosis may also result in an increased risk for pulmonary emboli, which can be prevented by anticoagulants.

A Cochrane review comparing pirfenidone with placebo, found a reduced risk of disease progression by 30%. FVC or VC was also improved, even if a mild slowing in FVC decline could be demonstrated only in one of the two CAPACITY trials. A third study, which was completed in 2014 found reduced decline in lung function and IPF disease progression. The data from the ASCEND study were also pooled with data from the two CAPACITY studies in a pre-specified analysis which showed that pirfenidone reduced the risk of death by almost 50% over one year of treatment.

A number of treatments have been investigated in the past for IPF, including interferon gamma-1β, bosentan, ambrisentan, and anticoagulants, but these are no longer considered effective treatment options. Many of these earlier studies were based on the hypothesis that IPF is an inflammatory disorder.

The dual (ET and ET) endothelin receptor antagonist bosentan was approved in 2001. Sitaxentan (Thelin) was approved for use in Canada, Australia, and the European Union, but not in the United States. In 2010, Pfizer withdrew Thelin worldwide because of fatal liver complications. A similar drug, ambrisentan is marketed as Letairis in the U.S. by Gilead Sciences.

PAM is one of the rare lung diseases currently being studied by the Rare Lung Diseases Consortium (RLDC). Pulmonary Alveolar Microlithiasis patients, families, and caregivers are encouraged to join the NIH Rare Lung Diseases Consortium Contact Registry. This is a privacy protected site that provides up-to-date information for individuals interested in the latest scientific news, trials, and treatments related to rare lung diseases.

The U.S. FDA approved sildenafil, a selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5), for the treatment of PAH in 2005. It is marketed for PAH as Revatio. In 2009, they also approved tadalafil, another PDE5 inhibitor, marketed under the name Adcirca. PDE5 inhibitors are believed to increase pulmonary artery vasodilation, and inhibit vascular remodeling, thus lowering pulmonary arterial pressure and pulmonary vascular resistance.

Tadalafil is taken orally, as well as sildenafil, and it is rapidly absorbed (serum levels are detectable at 20 minutes). The T (biological half-life) hovers around 17.5 hours in healthy subjects. Moreover, if we consider pharmacoeconomic implications, patients that take tadalafil would pay two-thirds of the cost of sildenafil therapy. However, there are some adverse effects of this drug such as headache, diarrhea, nausea, back pain, dyspepsia, flushing and myalgia.

ILD is not a single disease, but encompasses many different pathological processes. Hence treatment is different for each disease.

If a specific occupational exposure cause is found, the person should avoid that environment. If a drug cause is suspected, that drug should be discontinued.

Many cases due to unknown or connective tissue-based causes are treated with corticosteroids, such as prednisolone. Some people respond to immunosuppressant treatment. Patients with a low level of oxygen in the blood may be given supplemental oxygen.

Pulmonary rehabilitation appears to be useful. Lung transplantation is an option if the ILD progresses despite therapy in appropriately selected patients with no other contraindications.

On October 16, 2014, the Food and Drug Administration approved a new drug for the treatment of Idiopathic Pulmonary Fibrosis (IPF). This drug, Ofev (nintedanib), is marketed by Boehringer Ingelheim Pharmaceuticals, Inc. This drug has been shown to slow the decline of lung function although the drug has not been shown to reduce mortality or improve lung function. The estimated cost of the drug per year is approximately $94,000.

To date, no treatment has been proven to effectively reverse or prevent the progression of PAM. Lung transplantation is an option for end stage disease, but is typically only recommended as a last resort when quality of life is significantly impaired.

Etidronate is a bisphosphonate and can reduce the formation of calcium hydroxyapatite crystals. It has led to clinical and radiological improvements in few cases.

The National Institute of Occupational Safety and Health, Japan (JNIOSH) set limits for acceptable exposure at 0.0003 mg/m after the discovery of indium lung. Methods for reducing indium exposure are thought to be the best mode of protection. Medical surveillance of indium workers is also a method of prevention.

It is unclear as of 2014 if ursodeoxycholic acid is useful for those with cystic fibrosis-related liver disease.

There is no standardized treatment for indium lung disease. Treatment options include pulmonary lavage and corticosteroid therapy. Prognostic factors were a matter of research as of 2012, but preliminary evidence suggests that duration of employment and reported use of respiratory protection are not prognostic factors, but the serum level of indium may be a prognostic factor - higher levels of serum indium have been associated with worse prognoses. Indium lung disease has been fatal in several cases.

Lung cancer may be related to indium lung disease, though indium is not a known carcinogen.

Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of lung diseases affecting the interstitium (the tissue and space around the air sacs of the lungs). It concerns alveolar epithelium, pulmonary capillary endothelium, basement membrane, perivascular and perilymphatic tissues. It may occur when an injury to the lungs triggers an abnormal healing response. Ordinarily, the body generates just the right amount of tissue to repair damage. But in interstitial lung disease, the repair process goes awry and the tissue around the air sacs (alveoli) becomes scarred and thickened. This makes it more difficult for oxygen to pass into the bloodstream. The term ILD is used to distinguish these diseases from obstructive airways diseases.

In children, several unique forms of ILD exist which are specific for the young age groups. The acronym chILD is used for this group of diseases and is derived from the English name, Children’s Interstitial Lung Diseases – chILD.

Prolonged ILD may result in pulmonary fibrosis, but this is not always the case. Idiopathic pulmonary fibrosis is interstitial lung disease for which no obvious cause can be identified (idiopathic), and is associated with typical findings both radiographic (basal and pleural based fibrosis with honeycombing) and pathologic (temporally and spatially heterogeneous fibrosis, histopathologic honeycombing and fibroblastic foci).

In 2013 interstitial lung disease affected 595,000 people globally. This resulted in 471,000 deaths.

Several mechanical techniques are used to dislodge sputum and encourage its expectoration. In the hospital setting, chest physiotherapy is used; a respiratory therapist percusses an individual's chest by hand several times a day, to loosen up secretions. Chest physiotherapy is beneficial for short-term airway clearance. Devices that recreate this percussive therapy include the ThAIRapy Vest and the intrapulmonary percussive ventilator. Other methods such as biphasic cuirass ventilation, and associated clearance mode available in such devices, integrate a cough assistance phase, as well as a vibration phase for dislodging secretions. These are portable and adapted for home use.

Ivacaftor is a medication taken by mouth for the treatment of CF due to a number of specific mutations. It improves lung function by about 10%; however, as of 2014 it is expensive.

Aerosolized medications that help loosen secretions include dornase alfa and hypertonic saline. Dornase is a recombinant human deoxyribonuclease, which breaks down DNA in the sputum, thus decreasing its viscosity. Denufosol, an investigational drug, opens an alternative chloride channel, helping to liquefy mucus. Whether inhaled corticosteroids are useful is unclear, but stopping inhaled corticosteroid therapy is safe. There is weak evidence that corticosteroid treatment may cause harm by interfering with growth.

As lung disease worsens, mechanical breathing support may become necessary. Individuals with CF may need to wear special masks at night to help push air into their lungs. These machines, known as bilevel positive airway pressure (BiPAP) ventilators, help prevent low blood oxygen levels during sleep. Non-invasive ventilators may be used during physical therapy to improve sputum clearance. It is not known if this type of therapy has an impact on pulmonary exacerbations or disease progression. It is not known what role non-invasive ventilation therapy has for improving exercise capacity in people with cystic fibrosis. During severe illness, a tube may be placed in the throat (a procedure known as a tracheostomy) to enable breathing supported by a ventilator.

For children, preliminary studies show massage therapy may help people and their families' quality of life. Pneumococcal vaccination has not been studied as of 2014.

Some lung infections require surgical removal of the infected part of the lung. If this is necessary many times, lung function is severely reduced.

Regardless of cause, UIP is relentlessly progressive, usually leading to respiratory failure and death without a lung transplant. Some patients do well for a prolonged period of time, but then deteriorate rapidly because of a superimposed acute illness (so-called "accelerated UIP"). The outlook for long-term survival is poor. In most studies, the median survival is 3 to 4 years. Patients with UIP in the setting of rheumatoid arthritis have a slightly better prognosis than UIP without a known cause (IPF).

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.

Many people with this condition have no symptoms. Treatment is aimed at the health problems causing the lung problem and the complications caused by the disorder.

Fast-acting drugs for RA include aspirin and corticosteroids, which alleviate pain and reduce inflammation. Slow-acting drugs termed disease modifying antirheumatic drugs (DMARDs), include gold, methotrexate and hydroxychloroquine (Plaquenil), which promote disease remission and prevent progressive joint destruction. In patients with less severe RA, pain relievers, anti-inflammatory drugs and physical rest are sufficient to improve quality of life. In patients with joint deformity, surgery is the only alternative for recovering articular function.

Prognosis is related to the underlying disorder and the type and severity of lung disease. In severe cases, lung transplantation can be considered. This is more common in cases of bronchiolitis obliterans, pulmonary fibrosis, or pulmonary hypertension. Most complications are not fatal, but does reduce life expectancy to an estimated 5 to 10 years.

Restrictive lung diseases (or restrictive ventilatory defects) are a category of extrapulmonary, pleural, or parenchymal respiratory diseases that restrict lung expansion, resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation. Pulmonary function test demonstrates a decrease in the forced vital capacity.

Usual interstitial pneumonia (UIP) is a form of lung disease characterized by progressive scarring of both lungs. The scarring (fibrosis) involves the supporting framework (interstitium) of the lung. UIP is thus classified as a form of interstitial lung disease. The term "usual" refers to the fact that UIP is the most common form of interstitial fibrosis. "Pneumonia" indicates "lung abnormality", which includes fibrosis and inflammation. A term previously used for UIP in the British literature is cryptogenic fibrosing alveolitis, a term that has fallen out of favor since the basic underlying pathology is now thought to be fibrosis, not inflammation.

Within all classes of medicinal drugs that possibly can lead to pulmonary toxicity as a side effect, most pulmonary toxicity is due to chemotherapy for cancer.

Many medicinal drugs can lead to pulmonary toxicity. A few medicinal drugs can lead to pulmonary toxicity frequently (in medicine defined by international regulatory authorities such as the U.S. Food and Drug Administration and the EMEA [European Union] as > 1% and 10%). These medicinal drugs can include gold and nitrofurantoin, as well as the following drugs used in chemotherapy for cancer: Methotrexate, the taxanes (paclitaxel and docetaxel), gemcitabine, bleomycin, mitomycin C, busulfan, cyclophosphamide, chlorambucil, and nitrosourea (e.g., carmustine).

Also, some medicinal drugs used in cardiovascular medicine can lead to pulmonary toxicity frequently or very frequently. These include above all amiodarone, as well as beta blockers, ACE inhibitors (however, pulmonary toxicity of ACE inhibitors usually lasts only 3–4 months and then usually disappears by itself), procainamide, quinidine, tocainide, and minoxidil.

Both oncologists and cardiologists are well aware of possible pulmonary toxicity.

Obstructive lung disease is a category of respiratory disease characterized by airway obstruction. Many obstructive diseases of the lung result from narrowing (obstruction) of the smaller bronchi and larger bronchioles, often because of excessive contraction of the smooth muscle itself. It is generally characterized by inflamed and easily collapsible airways, obstruction to airflow, problems exhaling and frequent medical clinic visits and hospitalizations. Types of obstructive lung disease include; asthma, bronchiectasis, bronchitis and chronic obstructive pulmonary disease (COPD). Although COPD shares similar characteristics with all other obstructive lung diseases, such as the signs of coughing and wheezing, they are distinct conditions in terms of disease onset, frequency of symptoms and reversibility of airway obstruction. Cystic fibrosis is also sometimes included in obstructive pulmonary disease.

In order to prevent bronchiectasis, children should be immunized against measles, pertussis, pneumonia, and other acute respiratory infections of childhood. While smoking has not been found to be a direct cause of bronchiectasis, it is certainly an irritant that all patients should avoid in order to prevent the development of infections (such as bronchitis) and further complications.

Treatments to slow down the progression of this chronic disease include keeping bronchial airways clear and secretions weakened through various forms of pneumotherapy. Aggressively treating bronchial infections with antibiotics to prevent the destructive cycle of infection, damage to bronchial tubes, and more infection is also standard treatment. Regular vaccination against pneumonia, influenza and pertussis are generally advised. A healthy body mass index and regular doctor visits may have beneficial effects on the prevention of progressing bronchiectasis. The presence of hypoxemia, hypercapnia, dyspnea level and radiographic extent can greatly affect the mortality rate from this disease.

Untreated DPB leads to bronchiectasis, respiratory failure, and death. A journal report from 1983 indicated that untreated DPB had a five-year survival rate of 62.1%, while the 10-year survival rate was 33.2%. With erythromycin treatment, individuals with DPB now have a much longer life expectancy due to better management of symptoms, delay of progression, and prevention of associated infections like "P. aeruginosa". The 10-year survival rate for treated DPB is about 90%. In DPB cases where treatment has resulted in significant improvement, which sometimes happens after about two years, treatment has been allowed to end for a while. However, individuals allowed to stop treatment during this time are closely monitored. As DPB has been proven to recur, erythromycin therapy must be promptly resumed once disease symptoms begin to reappear. In spite of the improved prognosis when treated, DPB currently has no known cure.

Macrolide antibiotics, such as erythromycin, are an effective treatment for DPB when taken regularly over an extended period of time. Clarithromycin or roxithromycin are also commonly used. The successful results of macrolides in DPB and similar lung diseases stems from managing certain symptoms through immunomodulation (adjusting the immune response), which can be achieved by taking the antibiotics in low doses. Treatment consists of daily oral administration of erythromycin for two to three years, an extended period that has been shown to dramatically improve the effects of DPB. This is apparent when an individual undergoing treatment for DPB, among a number of disease-related remission criteria, has a normal neutrophil count detected in BAL fluid, and blood gas (an arterial blood test that measures the amount of oxygen and carbon dioxide in the blood) readings show that free oxygen in the blood is within the normal range. Allowing a temporary break from erythromycin therapy in these instances has been suggested, to reduce the formation of macrolide-resistant "P. aeruginosa". However, DPB symptoms usually return, and treatment would need to be resumed. Although highly effective, erythromycin may not prove successful in all individuals with the disease, particularly if macrolide-resistant "P. aeruginosa" is present or previously untreated DPB has progressed to the point where respiratory failure is occurring.

With erythromycin therapy in DPB, great reduction in bronchiolar inflammation and damage is achieved through suppression of not only neutrophil proliferation, but also lymphocyte activity and obstructive mucus and water secretions in airways. The antibiotic effects of macrolides are not involved in their beneficial effects toward reducing inflammation in DPB. This is evident because the treatment dosage is much too low to fight infection, and in DPB cases with the occurrence of macrolide-resistant "P. aeruginosa", erythromycin therapy still reduces inflammation.

A number of factors are involved in suppression of inflammation by erythromycin and other macrolides. They are especially effective at inhibiting the proliferation of neutrophils, by diminishing the ability of interleukin 8 and leukotriene B4 to attract them. Macrolides also reduce the efficiency of adhesion molecules that allow neutrophils to stick to bronchiolar tissue linings. Mucus production in the airways is a major culprit in the morbidity and mortality of DPB and other respiratory diseases. The significant reduction of inflammation in DPB attributed to erythromycin therapy also helps to inhibit the production of excess mucus.

Brown induration is fibrosis and hemosiderin pigmentation of the lungs due to long standing pulmonary congestion (chronic passive congestion).