A 2014 systematic review of clinical trials does not support using routine rapid viral testing to decrease antibiotic use for children in emergency departments. It is unclear if rapid viral testing in the emergency department for children with acute febrile respiratory infections reduces the rates of antibiotic use, blood testing, or urine testing. The relative risk reduction of chest x-ray utilization in children screened with rapid viral testing is 77% compared with controls. In 2013 researchers developed a breath tester that can promptly diagnose lung infections.

Normal surgical masks and N95 masks appear equivalent with respect to preventing respiratory infections.

Little is known in terms of effective means of prevention. Due to the low likelihood of transmission even from an infected mother, it is not recommended to expose the mother and child to the additional risks of caesarean section to prevent the transmission of this disease during vaginal childbirth. Opting for a caesarean section does not guarantee that transmission will not still occur.

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.

Laryngeal papillomatosis can be diagnosed through visualization of the lesions using one of several indirect laryngoscopy procedures. In indirect laryngoscopy, the tongue is pulled forward and a laryngeal mirror or a rigid scope is passed through the mouth to examine the larynx. Another variation of indirect laryngoscopy involves passing a flexible scope, known as a fiberscope or endoscope, through the nose and into the throat to visualize the larynx from above. This procedure is also called flexible fiberoptic laryngoscopy.

The appearance of papillomas has been described as multiple or rarely, single, white growths with a lumpy texture similar to cauliflower. Papillomas usually present in the larynx, especially on the vocal folds and in the space above the vocal folds called the ventricles. They can spread to other parts of the larynx and throughout the aerodigestive tract, from the mouth to the lower respiratory tract. Spread to regions beyond the larynx is more common in children then adults. Growths tend to be located at normal junctions in squamous and ciliated epithelium or at tissue junctions arising from injury.

A confirmatory diagnosis of laryngeal papillomatosis can only be obtained through a biopsy, involving microscopic examination and HPV testing of a sample of the growth. Biopsy samples are collected under general anesthesia, either through direct laryngoscopy or fiberoptic bronchoscopy.

Pulmonary aspiration resulting in pneumonia, in some patients, particularly those with physical limitations, can be fatal.

Antibiotics do not help the many lower respiratory infections which are caused by parasites or viruses. While acute bronchitis often does not require antibiotic therapy, antibiotics can be given to patients with acute exacerbations of chronic bronchitis. The indications for treatment are increased dyspnoea, and an increase in the volume or purulence of the sputum. The treatment of bacterial pneumonia is selected by considering the age of the patient, the severity of the illness and the presence of underlying disease. Amoxicillin and doxycycline are suitable for many of the lower respiratory tract infections seen in general practice.

The lungs are normally protected against aspiration by a series of "protective reflexes" such as coughing and swallowing. Significant aspiration can only occur if the protective reflexes are absent or severely diminished (in neurological disease, coma, drug overdose, sedation or general anesthesia). In intensive care, sitting patients up reduces the risk of pulmonary aspiration and ventilator-associated pneumonia.

Measures to prevent aspiration depend on the situation and the patient. In patients at imminent risk of aspiration, tracheal intubation by a trained health professional provides the best protection. A simpler intervention that can be implemented is to lay the patient on their side in the recovery position (as taught in first aid and CPR classes), so that any vomitus produced by the patient will drain out their mouth instead of back down their pharynx. Some anesthetists will use sodium citrate to neutralize the stomach's low pH and metoclopramide or domperidone (pro-kinetic agents) to empty the stomach.

People with chronic neurological disorders, for example, after a stroke, are less likely to aspirate thickened fluids.

The location of abscesses caused by aspiration depends on the position one is in. If one is sitting or standing up, the aspirate ends up in the posterior basal segment of the right lower lobe. If one is on one's back, it goes to the superior segment of the right lower lobe. If one is lying on the right side, it goes to the posterior segment of the right upper lobe, or the posterior basal segment of the right upper lobe. If one is lying on the left, it goes to the lingula.

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.

Respiratory diseases may be investigated by performing one or more of the following tests

- Biopsy of the lung or pleura

- Blood test

- Bronchoscopy

- Chest x-ray

- Computed tomography scan, including high-resolution computed tomography

- Culture of microorganisms from secretions such as sputum

- Ultrasound scanning can be useful to detect fluid such as pleural effusion

- Pulmonary function test

- Ventilation—perfusion scan

Lower respiratory tract infections place a considerable strain on the health budget and are generally more serious than upper respiratory infections.

Respiratory disease is a common and significant cause of illness and death around the world. In the US, approximately 1 billion "common colds" occur each year. A study found that in 2010, there were approximately 6.8 million emergency department visits for respiratory disorders in the U.S. for patients under the age of 18. In 2012, respiratory conditions were the most frequent reasons for hospital stays among children.

In the UK, approximately 1 in 7 individuals are affected by some form of chronic lung disease, most commonly chronic obstructive pulmonary disease, which includes asthma, chronic bronchitis and emphysema.

Respiratory diseases (including lung cancer) are responsible for over 10% of hospitalizations and over 16% of deaths in Canada.

In 2011, respiratory disease with ventilator support accounted for 93.3% of ICU utilization in the United States.

There is low or very-low quality evidence that probiotics may be better than placebo in preventing acute URTIs. Vaccination against influenza viruses, adenoviruses, measles, rubella, "Streptococcus pneumoniae", "Haemophilus influenzae", diphtheria, "Bacillus anthracis", and "Bordetella pertussis" may prevent them from infecting the URT or reduce the severity of the infection.

According to a Cochrane review, single oral dose of nasal decongestant in the common cold is modestly effective for the short term relief of congestion in adults; however, "there is insufficient data on the use of decongestants in children." Therefore, decongestants are not recommended for use in children under 12 years of age with the common cold. Oral decongestants are also contraindicated in patients with hypertension, coronary artery disease, and history of bleeding strokes.

In hospitalised patients who develop respiratory symptoms and fever, one should consider the diagnosis. The likelihood increases when upon investigation symptoms are found of respiratory insufficiency, purulent secretions, newly developed infiltrate on the chest X-Ray, and increasing leucocyte count. If pneumonia is suspected material from sputum or tracheal aspirates are sent to the microbiology department for cultures. In case of pleural effusion thoracentesis is performed for examination of pleural fluid. In suspected ventilator-associated pneumonia it has been suggested that bronchoscopy(BAL) is necessary because of the known risks surrounding clinical diagnoses.

In more severe cases, it is treated by administering intravenous antibiotics and may require admission to an intensive care unit (ICU) for intubation and supportive ventilation if the airway swelling is severe. During an intensive care admission, various methods of invasive and non-invasive monitoring may be required, which may include ECG monitoring, oxygen saturation, capnography and arterial blood pressure monitoring.

LPR presents with non-specific symptoms and signs that make differential diagnosis difficult to achieve. Furthermore, symptoms of the disorder overlap greatly with symptoms of other disorders. Therefore, LPR is under-diagnosed and under-treated. As there are multiple potential etiologies for the respiratory and laryngeal symptoms of LPR, diagnosing LPR based on symptoms alone is unreliable. Laryngoscopic findings such as erythema, edema, laryngeal granulomas, and interarytenoid hypertrophy have been used to establish the diagnosis; however, these findings are nonspecific and have been described in the majority of asymptomatic subjects undergoing laryngoscopy. Response to acid-suppression therapy has been suggested as a diagnostic tool for confirming diagnosis of LPR, but studies have shown that the response to empirical trials of such therapy (as with proton-pump inhibitors) in these patients is often disappointing. Several studies have emphasized the importance of measuring proximal esophageal, or ideally pharyngeal acid exposure, in patients with clinical symptoms of LPR to document reflux as the cause of the symptoms.

Additionally, several potential biomarkers of LPR have been investigated. These include inflammatory cytokines, carbonic anyhydrase, E-cadherin and mucins; however, their direct implications in LPR are still being established. The presence of pepsin, an enzyme produced in the stomach, in the hypopharynx has also become an increasingly researched biomarker for LPR. Research suggests that the stomach enzyme pepsin plays a crucial role in the complex mechanism behind LPR.

Before a diagnosis can be made, a physician will need to record the patient’s medical history and ask for details about the presenting symptoms. Questionnaires such as the Reflux Symptom Index (RSI), Quality-of-Life Index (QLI) for LPR, Glottal Closure/Function Index (GCI) and Voice Handicap Index (VHI) can be administered to gain information about the patient's medical history as well as their symptomatology. A physical examination will then need to be performed with particular concentration around the head and neck. A scope with a specialized camera lens made of fiber optic strands is gently fed down the throat and feeds back images to a monitor. This provides a clear view of the throat and larynx. Signs of LPR include redness, swelling, and obvious irritation. Other, more invasive tests, such as fibre-optic transnasal laryngoscopy, 24-hour ambulatory dual probe pHmetry, pharyngeal pHmetry, transnasal esophagoscopy (TNE) and biopsy may be used. A noninvasive test for diagnosis of LPR is the collection of refluxate where the refluxed material is collected and analyzed. Another noninvasive diagnostic test that can be used is an empirical trial of proton-pump inhibitor therapy; however, this test is mostly successful in diagnosing GERD.

There is no agreed-upon assessment technique to identify LPR in children. Of the debated diagnostic tools, multichannel intraluminal impedance with pH monitoring (MII-pH) is used as it recognizes both acid and non-acid reflux. A more common technique that is used is 24-hour dual probe pH monitoring. Both of these tools are expensive and are therefore not widely used.

Antigen detection, polymerase chain reaction assay, virus isolation, and serology can be used to identify adenovirus infections. Adenovirus typing is usually accomplished by hemagglutination-inhibition and/or neutralization with type-specific antisera. Since adenovirus can be excreted for prolonged periods, the presence of virus does not necessarily mean it is associated with disease.

Diagnosis of FVR is usually by clinical signs, especially corneal ulceration. Definitive diagnosis can be done by direct immunofluorescence or virus isolation. However, many healthy cats are subclinical carriers of feline herpes virus, so a positive test for FHV-1 does not necessarily indicate that signs of an upper respiratory tract infection are due to FVR. Early in the course of the disease, histological analysis of cells from the tonsils, nasal tissue, or nictitating membrane (third eyelid) may show inclusion bodies (a collection of viral particles) within the nucleus of infected cells.

Adenovirus can cause severe necrotizing pneumonia in which all or part of a lung has increased translucency radiographically, which is called Swyer-James Syndrome. Severe adenovirus pneumonia also may result in bronchiolitis obliterans, a subacute inflammatory process in which the small airways are replaced by scar tissue, resulting in a reduction in lung volume and lung compliance.

Bronchomalacia can best be described as a birth defect of the bronchus in the respiratory tract. Congenital malacia of the large airways is one of the few causes of irreversible airways obstruction in children, with symptoms varying from recurrent wheeze and recurrent lower airways infections to severe dyspnea and respiratory insufficiency. It may also be acquired later in life due to chronic or recurring inflammation resulting from infection or other airway disease.

CT scan can show the full extent of the polyp, which may not be fully appreciated with physical examination alone. Imaging is also required for planning surgical treatment. On a CT scan, a nasal polyp generally has an attenuation of 10–18 Hounsfield units, which is similar to that of mucus. Nasal polyps may have calcification.

Nasal polyps can be seen on physical examination inside of the nose and are often detected during the evaluation of symptoms. On examination, a polyp will appear as a visible mass in the nostril. Some polyps may be seen with anterior rhinoscopy (looking in the nose with a nasal speculum and a light), but frequently, they are farther back in the nose and must be seen by nasal endoscopy. Nasal endoscopy involves passing a small, rigid camera with a light source into the nose. An image is projected onto a screen in the office so the doctor can examine the nasal passages and sinuses in greater detail. The procedure is not generally painful, but the patient can be given a spray decongestant and local anesthetic to minimize discomfort.

Attempts have been made to develop scoring systems to determine the severity of nasal polyps. Proposed staging systems take into account the extent of polyps seen on endoscopic exam and the number of sinuses affected on CT imaging. This staging system is only partially validated, but in the future, may be useful for communicating the severity of disease, assessing treatment response, and planning treatment.

Tracheitis is an inflammation of the trachea.

Although the trachea is usually considered part of the lower respiratory tract, in ICD-10 tracheitis is classified under "acute upper respiratory infections".

There is a vaccine for FHV-1 available (ATCvet code: , plus various combination vaccines), but although it limits or weakens the severity of the disease and may reduce viral shedding, it does not prevent infection with FVR. Studies have shown a duration of immunity of this vaccine to be at least three years. The use of serology to demonstrate circulating antibodies to FHV-1 has been shown to have a positive predictive value for indicating protection from this disease.