Some signs and symptoms indicate the need for early referral. These include

- Difficulty swallowing

- Vocal stridor

- Ear pain

- Recent weight loss

- History of smoking

- Current or recent radiotherapy treatment (in the neck region)

- Recent neck surgery or surgery involving endotracheal tubing

- Person is a professional voice user (teacher, singer, actor, call center worker, and so on)

Treatment is often supportive in nature, and depends on the severity and type of laryngitis (acute or chronic). General measures to relieve symptoms of laryngitis include behaviour modification, hydration and humidification.

Vocal hygiene (care of the voice) is very important to relieve symptoms of laryngitis. Vocal hygiene involves measures such as

- Resting the voice

- Drinking sufficient amounts of water

- Reducing caffeine and alcohol intake

- Stopping smoking

- Limiting throat clearing

Voice hygiene programs are given by speech-language pathologists. These programs typically include the following components:

- Addressing amount and type of voice use

- Reducing behaviours that are damaging to the vocal folds

- Increasing hydration

- Adjusting lifestyle (for example, limiting caffeine and managing medical conditions)

It is hard to differentiate a viral and a bacterial cause of a sore throat based on symptoms alone. Thus often a throat swab is done to rule out a bacterial cause.

The modified Centor criteria may be used to determine the management of people with pharyngitis. Based on 5 clinical criteria, it indicates the probability of a streptococcal infection.

One point is given for each of the criteria:

- Absence of a cough

- Swollen and tender cervical lymph nodes

- Temperature >

- Tonsillar exudate or swelling

- Age less than 15 (a point is subtracted if age >44)

The McIsaac criteria adds to the Centor:

- Age less than 15: add one point

- Age greater than 45: subtract one point

The Infectious Disease Society of America however recommends against empirical treatment and considers antibiotics only appropriate following positive testing. Testing is not needed in children under three as both group A strep and rheumatic fever are rare, except if they have a sibling with the disease.

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.

The diagnosis of a throat irritation include a physical exam and throat culture.

The Centers for Disease Control describe protocol for treating sinusitis while at the same time discouraging overuse of antibiotics:

- Target likely organisms with first-line drugs: Amoxicillin, Amoxicillin/Clavulanate

- Use shortest effective course: Should see improvement in 2–3 days. Continue treatment for 7 days after symptoms improve or resolve (usually a 10–14 day course).

- Consider imaging studies in recurrent or unclear cases: some sinus involvement is frequent early in the course of uncomplicated viral URI

Treatment comprises symptomatic support usually via analgesics for headache, sore throat and muscle aches. Moderate exercise in sedentary subjects with naturally acquired URTI probably does not alter the overall severity and duration of the illness. No randomized trials have been conducted to ascertain benefits of increasing fluid intake.

Acute pharyngitis is the most common cause of a sore throat and, together with cough, it is diagnosed in more than 1.9 million people a year in the United States.

A throat culture is the gold standard for the diagnosis of streptococcal pharyngitis, with a sensitivity of 90–95%. A rapid strep test (also called rapid antigen detection testing or RADT) may also be used. While the rapid strep test is quicker, it has a lower sensitivity (70%) and statistically equal specificity (98%) as a throat culture. In areas of the world where rheumatic fever is uncommon, a negative rapid strep test is sufficient to rule out the disease.

A positive throat culture or RADT in association with symptoms establishes a positive diagnosis in those in which the diagnosis is in doubt. In adults, a negative RADT is sufficient to rule out the diagnosis. However, in children a throat culture is recommended to confirm the result. Asymptomatic individuals should not be routinely tested with a throat culture or RADT because a certain percentage of the population persistently "carries" the streptococcal bacteria in their throat without any harmful results.

As the symptoms of streptococcal pharyngitis overlap with other conditions, it can be difficult to make the diagnosis clinically. Coughing, nasal discharge, diarrhea, and red, irritated eyes in addition to fever and sore throat are more indicative of a viral sore throat than of strep throat. The presence of marked lymph node enlargement along with sore throat, fever, and tonsillar enlargement may also occur in infectious mononucleosis.

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.

The majority of cases of throat irritation usually go away without any treatment. There is no real treatment for throat irritation from a virus. If you have difficulty swallowing then one should drink liquids, suck on lozenges, ice chips or mix salt with warm water to gargle. Bacterial infections generally require antibiotics.

Home remedies for throat irritation include gargling with warm water twice a day, sipping honey and lemon mixture or sucking on medicated lozenges. If the cause is dry air, then one should humidify the home. Since smoke irritates the throat, stop smoking and avoid all fumes from chemicals, paints and volatile liquids.

Rest your voice if you have been screaming or singing. If you have pharyngitis, avoid infecting others by covering your mouth when coughing and wear a mask.

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.

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

Vaccination helps prevent bronchopneumonia, mostly against influenza viruses, adenoviruses, measles, rubella, streptococcus pneumoniae, haemophilus influenzae, diphtheria, bacillus anthracis, chickenpox, and bordetella pertussis.

Rhinitis medicamentosa is a form of drug-induced nonallergic rhinitis which is associated with nasal congestion brought on by the use of certain oral medications (primarily sympathomimetic amine and 2-imidazoline derivatives) and topical decongestants (e.g., oxymetazoline, phenylephrine, xylometazoline, and naphazoline nasal sprays) that constrict the blood vessels in the lining of the nose.

In the case of infectious rhinitis, vaccination against influenza viruses, adenoviruses, measles, rubella, "Streptococcus pneumoniae", "Haemophilus influenzae", diphtheria, "Bacillus anthracis", and "Bordetella pertussis" may help prevent it.

Chicken respiratory diseases are difficult to differentiate and may not be diagnosed based on respiratory signs and lesions. Other diseases such as mycoplasmosis by Mycoplasma gallisepticum (chronic respiratory disease), Newcastle disease by mesogenic strains of Newcastle diseases virus (APMV-1), avian metapneumovirus, infectious laryngotracheitis, avian infectious coryza in some stages may clinically resemble IB. Similar kidney lesions may be caused by different etiologies, including other viruses, such as infectious bursal disease virus (the cause of Gumboro disease) and toxins (for instance ochratoxins of Aspergillus ochraceus), and dehydration.

In laying hens, abnormal and reduced egg production are also observed in Egg Drop Syndrome 76 (EDS), caused by an Atadenovirus and avian metapneumovirus infections. At present, IB is more common and far more spread than EDS. The large genetic and phenotypic diversity of IBV have been resulting in common vaccination failures. In addition, new strains of IBV, not present in commercial vaccines, can cause the disease in IB vaccinated flocks. Attenuated vaccines will revert to virulence by consecutive passage in chickens in densely populated areas, and may reassort with field strains, generating potentially important variants.

Definitive diagnosis relies on viral isolation and characterization. For virus characterization, recent methodology using genomic amplification (PCR) and sequencing of products, will enable very precise description of strains, according to the oligonucleotide primers designed and target gene. Methods for IBV antigens detection may employ labelled antibodies, such as direct immunofluorescence or immunoperoxidase. Antibodies to IBV may be detected by indirect immunofluorescent antibody test, ELISA and Haemagglutination inhibition (haemagglutinating IBV produced after enzymatic treatment by phospholipase C).

No specific treatment is available, but antibiotics can be used to prevent secondary infections.

Vaccines are available (ATCvet codes: for the inactivated vaccine, for the live vaccine; plus various combinations).

Biosecurity protocols including adequate isolation, disinfection are important in controlling the spread of the disease.

Diagnosis is made by history and examination.

In immunocompromised patients, pus is present in the urine but often no organism can be cultured. In children, polymerase chain reaction sequencing of urine can detect fragments of the infectious agent.

The procedure differs somewhat for women and men. Laboratory testing of urine samples now can be performed with dipsticks that indicate immune system responses to infection, as well as with microscopic analysis of samples. Normal human urine is sterile. The presence of bacteria or pus in the urine usually indicates infection. The presence of hematuria, or blood in the urine, may indicate acute UTIs, kidney disease, kidney stones, inflammation of the prostate (in men), endometriosis (in women), or cancer of the urinary tract. In some cases, blood in the urine results from athletic training, particularly in runners.

The heterophile antibody test works by agglutination of red blood cells from guinea pig, sheep and horse. This test is specific but not particularly sensitive (with a false-negative rate of as high as 25% in the first week, 5–10% in the second, and 5% in the third). About 90% of patients have heterophile antibodies by week 3, disappearing in under a year. The antibodies involved in the test do not interact with the Epstein–Barr virus or any of its antigens.

The monospot test is not recommended for general use by the CDC due to its poor accuracy.

About 10% of people who present a clinical picture of infectious mononucleosis do not have an acute Epstein–Barr-virus infection. A differential diagnosis of acute infectious mononucleosis needs to take into consideration acute cytomegalovirus infection and "Toxoplasma gondii" infections. Because their management is much the same, it is not always helpful, or possible, to distinguish between Epstein–Barr-virus mononucleosis and cytomegalovirus infection. However, in pregnant women, differentiation of mononucleosis from toxoplasmosis is important, since it is associated with significant consequences for the fetus.

Acute HIV infection can mimic signs similar to those of infectious mononucleosis, and tests should be performed for pregnant women for the same reason as toxoplasmosis.

People with infectious mononucleosis are sometimes misdiagnosed with a streptococcal pharyngitis (because of the symptoms of fever, pharyngitis and adenopathy) and are given antibiotics such as ampicillin or amoxicillin as treatment.

Other conditions from which to distinguish infectious mononucleosis include leukemia, tonsillitis, diphtheria, common cold and influenza (flu).

A determination of whether or not the person has dehydration is an important part of the assessment, with dehydration typically divided into mild (3–5%), moderate (6–9%), and severe (≥10%) cases. In children, the most accurate signs of moderate or severe dehydration are a prolonged capillary refill, poor skin turgor, and abnormal breathing. Other useful findings (when used in combination) include sunken eyes, decreased activity, a lack of tears, and a dry mouth. A normal urinary output and oral fluid intake is reassuring. Laboratory testing is of little clinical benefit in determining the degree of dehydration. Thus the use of urine testing or ultrasounds is generally not needed.

Other potential causes of signs and symptoms that mimic those seen in gastroenteritis that need to be ruled out include appendicitis, volvulus, inflammatory bowel disease, urinary tract infections, and diabetes mellitus. Pancreatic insufficiency, short bowel syndrome, Whipple's disease, coeliac disease, and laxative abuse should also be considered. The differential diagnosis can be complicated somewhat if the person exhibits "only" vomiting or diarrhea (rather than both).

Appendicitis may present with vomiting, abdominal pain, and a small amount of diarrhea in up to 33% of cases. This is in contrast to the large amount of diarrhea that is typical of gastroenteritis. Infections of the lungs or urinary tract in children may also cause vomiting or diarrhea. Classical diabetic ketoacidosis (DKA) presents with abdominal pain, nausea, and vomiting, but without diarrhea. One study found that 17% of children with DKA were initially diagnosed as having gastroenteritis.

Diagnosis of tenosynovitis is typically made clinically after a thorough patient history and physical exam. Aspirated fluid can also be cultured to identify the infectious organism. X-rays are typically unremarkable but can help rule out a broken bone or a foreign body

Acute infectious thyroiditis is very rare, with it only accounting for about 0.1–0.7% of all thyroiditis. Large hospitals tend to only see two cases of AIT annually. For the few cases of AIT that are seen the statistics seem to show a pattern. AIT is found in children and young adults between the ages of 20 and 40. The occurrence of the disease in people between 20 and 40 is only about 8% with the other 92% being in children. Men and women are each just as likely to get the disease. If left untreated, there is a 12% mortality rate.