"N"-Acetylcysteine (NAC) is a precursor to glutathione, an antioxidant. It has been hypothesized that treatment with high doses of NAC may repair an oxidant–antioxidant imbalance that occurs in the lung tissue of patients with IPF. In the first clinical trial of 180 patients (IFIGENIA), NAC was shown in previous study to reduce the decline in VC and DLCO over 12 months of follow-up when used in combination with prednisone and azathioprine (triple therapy).

More recently, a large randomized, controlled trial (PANTHER-IPF) was undertaken by the National Institutes of Health (NIH) in the USA to evaluate triple therapy and NAC monotherapy in IPF patients. This study found that the combination of prednisone, azathioprine, and NAC increased the risk of death and hospitalizations and the NIH announced in 2012 that the triple-therapy arm of the PANTHER-IPF study had been terminated early.

This study also evaluated NAC alone and the results for this arm of the study were published in May 2014 in the New England Journal of Medicine, concluding that "as compared with placebo, acetylcysteine offered no significant benefit with respect to the preservation of FVC in patients with idiopathic pulmonary fibrosis with mild-to-moderate impairment in lung function".

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.

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.

Corticosteroids are the mainstay of treatment of IPH, though they are controversial and lack clear evidence in their favour. They are thought to decrease the frequency of haemorrhage, while other studies suggest that they do not have any effect on the course or prognosis of this disease. In either case, steroid therapy has significant side effects. Small trials have investigated the use of other medications, but none has emerged as a clear standard of care. This includes immune modulators such as hydroxychloroquine, azathioprine, and cyclophosphamide. 6-mercaptopurine as a long-term therapy may prevent pulmonary haemorrhage. A 2007 scientific letter. reports preliminary success in preventing pulmonary haemorrhage with the anti-oxidant N-acetylcysteine.

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.

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.

The first advance in the treatment of pulmonary alveolar proteinosis came in November 1960, when Dr. Jose Ramirez-Rivera at the Veterans' Administration Hospital in Baltimore applied repeated "segmental flooding" as a means of physically removing the accumulated alveolar material.

The standard treatment for PAP is whole-lung lavage, in which the lung is filled with sterile fluid with subsequent removal of the fluid along with the abnormal surfactant material. This is generally effective at improving PAP symptoms, often for a prolonged period of time. Since the mouse discovery noted above, the use of GM-CSF injections has also been attempted, with variable success. Lung transplantation can be performed in refractory cases.

Most patients recover with corticosteroid therapy. A standardized approach to dosing starting at 0.75 mg/kg and weaning over 24 weeks has been shown to reduce total corticosteroid exposure without affecting outcome.

About two thirds of patients recover with corticosteroid therapy: the usual corticosteroid administered is prednisolone in Europe and prednisone in the USA; these differ by only one functional group and have the same clinical effect. The corticosteroid is initially administered in high dosage, typically 50 mg per day tapering down to zero over a six-month to one-year period. If the corticosteroid treatment is halted too quickly the disease may return. Other medications must be taken to counteract side effects of the steroid.

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.

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.

To date there have been no clinical trials to determine effective treatment for this disease. Some patients have been treated with somatostatin analogs. Although the cough associated with DIPNECH tends to diminish on this treatment, improvement in pulmonary function has not been clearly demonstrated. There are also reports of symptomatic treatment with long- and short-acting beta agonists. Although steroids, both oral and inhaled, have been used in the setting of DIPNECH, there is no clear improvement with this treatment.

It is not uncommon for typical carcinoids to arise within DIPNECH. Due to presence of these tumors, DIPNECH is classified as a pre-malignant condition. Although there have been reports of atypical carcinoids with local lymph node involvement, there are no reports of more aggressive neuroendocrine tumors, such as large cell neuroendocrine or small cell lung cancer, associated with DIPNECH. When isolated bronchial carcinoids are diagnosed, oncology guidelines recommend surgical resection with lymph node sampling. However, as multiple carcinoids may develop in the setting of DIPNECH, a more conservative approach is often considered to preserve lung function.

Treatment depends on the underlying cause. Treatments include iced saline, and topical vasoconstrictors such as adrenalin or vasopressin. Selective bronchial intubation can be used to collapse the lung that is bleeding. Also, endobronchial tamponade can be used. Laser photocoagulation can be used to stop bleeding during bronchoscopy. Angiography of bronchial arteries can be performed to locate the bleeding, and it can often be embolized. Surgical option is usually the last resort, and can involve, removal of a lung lobe or removal of the entire lung. Non–small-cell lung cancer can also be treated with erlotinib or gefitinib. Cough suppressants can increase the risk of choking.

Sirolimus is an mTOR inhibitor that stabilizes lung function and improves some measures of life in LAM patients. It is approved by the FDA for use in LAM, based on the results of the Multicenter International LAM Efficacy and Safety of Sirolimus (MILES) Trial. MILES data supports the use of sirolimus in patients who have abnormal lung function (i.e. FEV1<70% predicted). Whether the benefits of treatment outweigh the risks for asymptomatic LAM patients with normal lung function is not clear, but some physicians consider treatment for declining patients who are approaching the abnormal range for FEV1. Sirolimus also appears to be effective for the treatment chylous effusions and lymphangioleiomyomatosis. The benefits of sirolimus only persist while treatment continues. The safety of long term therapy has not been studied.

Potential side effects from mTOR inhibitors include swelling in the ankles, acne, oral ulcers, dyspepsia, diarrhea, elevation of cholesterol and triglycerides, hypertension and headache. Sirolimus pneumonitis and latent malignancy are more serious concerns, but occur infrequently. Sirolimus inhibits wound healing. It is important to stop therapy with the drug for 1–2 weeks before and after elective procedures that require optimal wound healing. Precautions must be taken to avoid prolonged sun exposure due to increased skin cancer risk.

Treatment with another mTOR inhibitor, everolimus, was reported in a small, open-label trial to be associated with improvement in FEV1 and six-minute walk distance. Serum levels of VEGF-D and collagen IV were reduced by treatment. Adverse events were generally consistent with those known to be associated with mTOR inhibitors, although some were serious and included peripheral edema, pneumonia, cardiac failure and "Pneumocystis jirovecii" infection. Escalating doses of everolimus were used, up to 10 mg per day; higher than what is typically used clinically for LAM.

Serum VEGF-D concentration is useful, predictive and prognostic biomarker. Higher baseline VEGF-D levels predicts more rapid disease progression and a more robust treatment response.

Hormonal approaches to treatment have never been tested in proper trials. In the absence of proven benefit, therapy with progesterone, GnRh agonists (e.g., Lupron, goserelin) and tamoxifen are not routinely recommended. Doxycycline had no effect on the rate of lung function decline in a double blind trial.

Sirolimus is often effective as first-line management for chylothorax. If chylous leakage or accumulations persist despite treatment, imaging with heavy T2 weighted MRI, MRI lymphangiography or thoracic duct lymphangiography can be considered. Pleural fusion procedures can be considered in refractory cases.

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.

Treatment of bronchiectasis includes controlling infections and bronchial secretions, relieving airway obstructions, removal of affected portions of lung by surgical removal or artery embolization and preventing complications. The prolonged use of antibiotics prevents detrimental infections and decreases hospitalizations in people with bronchiectasis, but also increases the risk of people becoming infected with drug-resistant bacteria.

Other treatment options include eliminating accumulated fluid with postural drainage and chest physiotherapy. Postural drainage techniques, aided by physiotherapists and respiratory therapists, are an important mainstay of treatment. Airway clearance techniques appear useful.

Surgery may also be used to treat localized bronchiectasis, removing obstructions that could cause progression of the disease.

Inhaled steroid therapy that is consistently adhered to can reduce sputum production and decrease airway constriction over a period of time, and help prevent progression of bronchiectasis. This is not recommended for routine use in children. One commonly used therapy is beclometasone dipropionate.

Although not approved for use in any country, mannitol dry inhalation powder, has been granted orphan drug status by the FDA for use in people with bronchiectasis and with cystic fibrosis.

Treatment is directed at correcting the underlying cause. Post-surgical atelectasis is treated by physiotherapy, focusing on deep breathing and encouraging coughing. An incentive spirometer is often used as part of the breathing exercises. Walking is also highly encouraged to improve lung inflation. People with chest deformities or neurologic conditions that cause shallow breathing for long periods may benefit from mechanical devices that assist their breathing. One method is continuous positive airway pressure, which delivers pressurized air or oxygen through a nose or face mask to help ensure that the alveoli do not collapse, even at the end of a breath. This is helpful, as partially inflated alveoli can be expanded more easily than collapsed alveoli. Sometimes additional respiratory support is needed with a mechanical ventilator.

The primary treatment for acute massive atelectasis is correction of the underlying cause. A blockage that cannot be removed by coughing or by suctioning the airways often can be removed by bronchoscopy. Antibiotics are given for an infection. Chronic atelectasis is often treated with antibiotics because infection is almost inevitable. In certain cases, the affected part of the lung may be surgically removed when recurring or chronic infections become disabling or bleeding is significant. If a tumor is blocking the airway, relieving the obstruction by surgery, radiation therapy, chemotherapy, or laser therapy may prevent atelectasis from progressing and recurrent obstructive pneumonia from developing.

Estrogen-containing medications can exacerbate LAM and are contraindicated. Agents that antagonize the effects of estrogen have not been proven to be effective for treatment, but no proper trials have been done. A trial of bronchodilators should be considered in LAM patients, because up to 17% to 25% have bronchodilator-responsive airflow obstruction. Oxygen should be administered to maintain oxyhemoglobin saturations of greater than 90% with rest, exercise and sleep. Bone densitometry should be considered in all patients who are immobilized and/or on antiestrogen therapies, and appropriate therapy instituted for osteoporotic patients. Proper attention should be paid to cardiovascular health following natural or induced menopause. Immunizations for pneumococcus and influenza should be kept up to date. Pulmonary rehabilitation seems to be particularly rewarding in young, motivated patients with obstructive lung disease, but studies to assess this intervention's effect on exercise tolerance, conditioning and quality of life have not been done.

There is no cure available for asbestosis. Oxygen therapy at home is often necessary to relieve the shortness of breath and correct underlying low blood oxygen levels. Supportive treatment of symptoms includes respiratory physiotherapy to remove secretions from the lungs by postural drainage, chest percussion, and vibration. Nebulized medications may be prescribed in order to loosen secretions or treat underlying chronic obstructive pulmonary disease. Immunization against pneumococcal pneumonia and annual influenza vaccination is administered due to increased sensitivity to the diseases. Those with asbestosis are at increased risk for certain cancers. If the person smokes, quitting the habit reduces further damage. Periodic pulmonary function tests, chest x-rays, and clinical evaluations, including cancer screening/evaluations, are given to detect additional hazards.

Treatment is primarily supportive. Management in an intensive care unit is required and the need for mechanical ventilation is common. Therapy with corticosteroids is generally attempted, though their usefulness has not been established. The only treatment that has met with success to date is a lung transplant.

Radiation (radiotherapy) is frequently used for the treatment of many cancer types, and can be highly effective. Unfortunately, it also can lead to pulmonary toxicity as a side effect.

Radiotherapists are well aware of possible pulmonary toxicity, and take a number of precautions to minimise the incidence of this side effect. There are research efforts to possibly eliminate this side effect in the future.

When eosinophilic pneumonia is related to an illness such as cancer or parasitic infection, treatment of the underlying cause is effective in resolving the lung disease. When due to AEP or CEP, however, treatment with corticosteroids results in a rapid, dramatic resolution of symptoms over the course of one or two days. Either intravenous methylprednisolone or oral prednisone are most commonly used. In AEP, treatment is usually continued for a month after symptoms disappear and the x-ray returns to normal (usually four weeks total). In CEP, treatment is usually continued for three months after symptoms disappear and the x-ray returns to normal (usually four months total). Inhaled steroids such as fluticasone have been used effectively when discontinuation of oral prednisone has resulted in relapse.

Because EP affects the lungs, individuals with EP have difficulty breathing. If enough of the lung is involved, it may not be possible for a person to breathe without support. Non-invasive machines such as a bilevel positive airway pressure machine may be used. Otherwise, placement of a breathing tube into the mouth may be necessary and a ventilator may be used to help the person breathe.

There are no current guidelines available on the investigation and management of GLILD and evidence is restricted to retrospective case series. Because of the association with poorer outcomes, and because some patients develop advanced lung disease, most specialists now recommend treatment in early disease, but this is always an individual decision between patient and health-care team. Many centres screen for the development of GLILD (and other lung complications) using regular lung function tests and CT scans.

Studies of GLILD have been conducted in patients on background immunoglobulin replacement. In a cohort of 59 CVID patients with granulomatous disease, 30 (51%) of whom had lung involvement, complete remission of disease was obtained in 5 of 25 attempts using corticosteroids (three patients), methotrexate (1 patient) and cyclophosphamide (1 patient). Partial responses were also seen with rituximab and hydroxychloroquine. In contrast, a second report suggested poor response to corticosteroids alone, but a good response to 18-months treatment with rituximab and azathioprine in seven patients. Bone marrow transplantation has been attempted. Immunosuppression has been associated with development of opportunistic infection and other predictable side effects, and the balance of risks and benefits of therapy must be carefully weighed in each case. This may be best achieved by joint working between immunology, respiratory, radiology and pathology specialists, working as part of a multi-professional team with the patient.

Patients with single aspergillomas generally do well with surgery to remove the aspergilloma, and are best given pre-and post-operative antifungal drugs. Often, no treatment is necessary. However, if a patient coughs up blood (haemoptysis), treatment may be required (usually angiography and embolisation, surgery or taking tranexamic acid). Angiography (injection of dye into the blood vessels) may be used to find the site of bleeding which may be stopped by shooting tiny pellets into the bleeding vessel.

For chronic cavitary pulmonary aspergillosis and chronic fibrosing pulmonary aspergillosis, lifelong use of antifungal drugs is usual. Itraconazole and voriconazole are first and second-line anti fungal agents respectively. Posaconazole can be used as third-line agent, for patients who are intolerant of or developed resistance to the first and second-line agents. Regular chest X-rays, serological and mycological parameters as well as quality of life questionnaires are used to monitor treatment progress. It is important to monitor the blood levels of antifungals to ensure optimal dosing as individuals vary in their absorption levels of these drugs.