The following is a list of common signs and symptoms found with neonatal meningitis.

- Fever

- poor appetite

- anterior fontanelle bulging

- seizure

- jitteriness

- dyspnea

- irritability

- anorexia

- vomiting

- diarrhea

- abdominal distention (increase in abdominal size)

- neck rigidity

- cyanosis

- jaundice

- and sunset eyes (downward gaze of the eyes)

- abnormal body temperature (hypo-or hyperthermia)

- change of activity (lethargy or irritability)

Unfortunately these symptoms are unspecific and may point to many different conditions.

Possible symptoms of "Haemophilus" meningitis include:

- Nausea or vomiting

- Fever

- Headache

- Sensitivity to light

- Seizures

- Anorexia

- change in mental status, such as irritability

- stiff neck

Pharyngitis is a type of inflammation, most commonly caused by an upper respiratory tract infection. It may be classified as acute or chronic. Acute pharyngitis may be catarrhal, purulent or ulcerative, depending on the causative agent and the immune capacity of the affected individual. Chronic pharyngitis may be catarrhal, hypertrophic or atrophic.

Tonsillitis is a sub type of pharyngitis. If the inflammation includes both the tonsils and other parts of the throat, it may be called pharyngotonsillitis. Another sub classification is nasopharyngitis (the common cold).

"Haemophilus" meningitis is a form of bacterial meningitis caused by the "Haemophilus influenzae" bacteria. It is usually (but not always) associated with "Haemophilus influenzae" type b. Meningitis involves the inflammation of the protective membranes that cover the brain and spinal cord. "Haemophilus" meningitis is characterized by symptoms including fever, nausea, sensitivity to light, headaches, stiff neck, anorexia, and seizures. "Haemophilus" meningitis can be deadly, but antibiotics are effective in treating the infection, especially when cases are caught early enough that the inflammation has not done a great deal of damage. Before the introduction of the Hib vaccine in 1985, Haemophilus meningitis was the leading cause of bacterial meningitis in children under the age of five. However, since the creation of the Hib vaccine, only two in every 100,000 children contract this type of meningitis. Five to ten percent of cases can be fatal, although the average mortality rate in developing nations is seventeen percent, mostly due to lack of access to vaccination as well as lack of access to medical care needed to combat the meningitis.

Neonatal meningitis is a serious medical condition in infants. Meningitis is an inflammation of the meninges (the protective membranes of the central nervous system (CNS)) and is more common in the neonatal period (infants less than 44 days old) than any other time in life and is an important cause of morbidity and mortality globally. Mortality is roughly half in developing countries and ranges from 8%-12.5% in developed countries.

Symptoms seen with neonatal meningitis are often unspecific that may point to several conditions, such as sepsis (whole body inflammation). These can include fever, irritability, and dyspnea. The only method to determine if meningitis is the cause of these symptoms is lumbar puncture (LP; an examination of the cerebrospinal fluid).

The most common causes of neonatal meningitis is bacterial infection of the blood, known as bacteremia (specifically Group B "Streptococci" (GBS; "Streptococcus agalactiae"), "Escherichia coli", and "Listeria monocytogenes"). Although there is a low mortality rate in developed countries, there is a 50% prevalence rate of neurodevelopmental disabilities in "E. coli" and GBS meningitis, while having a 79% prevalence for non-"E. coli" Gram-negative caused meningitis. Delayed treatment of neonatal meningitis may cause include cerebral palsy, blindness, deafness, and learning deficiencies.

"Mycoplasma" pneumonia (also known as "walking pneumonia" because it can spread bilaterally (“walk”) from one lung to the other) is a form of bacterial pneumonia caused by the bacterial species "Mycoplasma pneumoniae".

The majority of cases are due to an infectious organism acquired from close contact with an infected individual.

Historically, six "classical" infectious childhood exanthems have been recognized, four of which are viral. Numbers were provided in 1905.

The four viral exanthema have much in common, and are often studied together as a class. They are:

Scarlet fever, or "second disease", is associated with the bacterium "Streptococcus pyogenes". Fourth disease, a condition whose existence is not widely accepted today, was described in 1900 and is postulated to be related to the bacterium "Staphylococcus aureus".

Many other common viruses apart from the ones mentioned above can also produce an exanthem as part of their presentation, though they are not considered part of the classic numbered list:

- Varicella zoster virus (chickenpox or shingles)

- Mumps

- rhinovirus (the common cold)

- unilateral laterothoracic exanthem of childhood

- Some types of viral haemorrhagic fever are also known to produce a systemic rash of this kind during the progression of the disease.

- Tick-borne diseases like Rocky Mountain spotted fever produce a rash that may become extensive enough so as to be classified as exanthemous in as many as 90% of children with the disease.

Among the signs of subacute bacterial endocarditis are:

- Malaise

- Weakness

- Excessive sweat

- Fever

An exanthem or exanthema (from Greek ἐξάνθημα "exánthēma", "a breaking out") is a widespread rash usually occurring in children. An exanthem can be caused by toxins, drugs, or microorganisms, or can result from autoimmune disease.

It can be contrasted with an enanthem.

Symptoms are different for every person depending on the type of rat-bite fever with which the person is infected. Both spirillary and streptobacillary rat-bite fever have a few individual symptoms, although most symptoms are shared. Streptobacillosis is most commonly found in the United States and spirillary rat-bite fever is generally diagnosed in patients in Africa. Rat-bite symptoms are visually seen in most cases and include inflammation around the open sore. A rash can also spread around the area and appear red or purple. Other symptoms associated with streptobacillary rat-bite fever include chills, fever, vomiting, headaches, and muscle aches. Joints can also become painfully swollen and pain can be experienced in the back. Skin irritations such as ulcers or inflammation can develop on the hands and feet. Wounds heal slowly, so symptoms possibly come and go over the course of a few months.

Symptoms associated with spirillary rat-bite fever include issues with the lymph nodes, which often swell or become inflamed as a reaction to the infection. The most common locations of lymph node swelling are in the neck, groin, and underarm. Symptoms generally appear within 2 to 10 days of exposure to the infected animal. It begins with the fever and progresses to the rash on the hands and feet within 2 to 4 days. Rash appears all over the body with this form, but rarely causes joint pain.

Croup is characterized by a "barking" cough, stridor, hoarseness, and difficulty breathing which usually worsens at night. The "barking" cough is often described as resembling the call of a seal or sea lion. The stridor is worsened by agitation or crying, and if it can be heard at rest, it may indicate critical narrowing of the airways. As croup worsens, stridor may decrease considerably.

Other symptoms include fever, coryza (symptoms typical of the common cold), and indrawing of the chest wall–known as Hoover's sign. Drooling or a very sick appearance indicate other medical conditions, such as epiglottitis.

An "Arcanobacterium haemolyticum" infection is any of several types of infection with the gram-positive bacillus "Arcanobacterium haemolyticum". It can cause an acute pharyngitis, and it may cause an exanthem characterized by an erythematous, morbilliform or scarlatiniform eruption involving the trunk and extremities.

Acute adenoiditis is characterized by fever, runny nose, nasal airway obstruction resulting in predominantly oral breathing, snoring and sleep apnea, Rhinorrhea with serous secretion in viral forms and mucous-purulent secretion in bacterial forms. In cases due to viral infection symptoms usually recede spontaneously after 48 hours, symptoms of bacterial adenoiditis typically persist up to a week. Adenoiditis is sometimes accompanied by tonsillitis. Repeated adenoiditis may lead to enlarged adenoids.

The streptobacillosis form of rat-bite fever is known by the alternative names Haverhill fever and epidemic arthritic erythema. It is a severe disease caused by "Streptobacillus moniliformis", transmitted either by rat bite or ingestion of contaminated products (Haverhill fever). After an incubation period of 2–10 days, Haverhill fever begins with high prostrating fevers, rigors (shivering), headache, and polyarthralgia (joint pain). Soon, an exanthem (widespread rash) appears, either maculopapular (flat red with bumps) or petechial (red or purple spots) and arthritis of large joints can be seen. The organism can be cultivated in blood or articular fluid. The disease can be fatal if untreated in 20% of cases due to malignant endocarditis, meningoencephalitis, or septic shock. Treatment is with penicillin, tetracycline, or doxycycline.

Bacterial pneumonia is a type of pneumonia caused by bacterial infection.

Croup, also known as laryngotracheobronchitis, is a type of respiratory infection that is usually caused by a virus. The infection leads to swelling inside the trachea, which interferes with normal breathing and produces the classic symptoms of "barking" cough, stridor, and a hoarse voice. Fever and runny nose may also be present. These symptoms may be mild, moderate, or severe. Often it starts or is worse at night. It normally lasts one to two days.

Croup can be caused by a number of viruses including parainfluenza and influenza virus. Rarely is it due to a bacterial infection. Croup is typically diagnosed based on signs and symptoms after potentially more severe causes, such as epiglottitis or an airway foreign body, have been ruled out. Further investigations—such as blood tests, X-rays, and cultures—are usually not needed.

Many cases of croup are preventable by immunization for influenza and diphtheria. Croup is usually treated with a single dose of steroids by mouth. In more severe cases inhaled epinephrine may also be used. Hospitalization is required in one to five percent of cases.

Croup is a relatively common condition that affects about 15% of children at some point. It most commonly occurs between 6 months and 5 years of age but may rarely be seen in children as old as fifteen. It is slightly more common in males than females. It occurs most often in autumn. Before vaccination, croup was frequently caused by diphtheria and was often fatal. This cause is now very rare in the Western world due to the success of the diphtheria vaccine.

Adenoiditis is the inflammation of the adenoid tissue, usually caused by an infection. Adenoiditis is treated using medication (antibiotics and/or steroids) or surgical intervention.

Adenoiditis may produce cold-like symptoms. However, adenoiditis symptoms often persist for ten or more days, and often include pus-like discharge from nose.

The infection cause is usually viral. However, if the adenoiditis is caused by a bacterial infection, antibiotics may be prescribed for treatment. A steroidal nasal spray may also be prescribed in order to reduce nasal congestion. Severe or recurring adenoiditis may require surgical removal of the adenoids (adenotonsillectomy).

"Streptococcus pneumoniae" () is the most common bacterial cause of pneumonia in all age groups except newborn infants. "Streptococcus pneumoniae" is a Gram-positive bacterium that often lives in the throat of people who do not have pneumonia.

Other important Gram-positive causes of pneumonia are "Staphylococcus aureus" () and "Bacillus anthracis".

Subacute bacterial endocarditis (also called endocarditis lenta) is a type of endocarditis (more specifically, infective endocarditis). Subacute bacterial endocarditis can be considered a form of type III hypersensitivity.

Initial signs of FVR include coughing, sneezing, nasal discharge, conjunctivitis, and sometimes fever (up to 106) and loss of appetite. These usually resolve within four to seven days, but secondary bacterial infections can cause the persistence of clinical signs for weeks. Frontal sinusitis and empyema can also result.

FHV-1 also has a predilection for corneal epithelium, resulting in corneal ulcers, often pinpoint or dendritic in shape. Other ocular signs of FHV-1 infection include conjunctivitis, keratitis, keratoconjunctivitis sicca (decreased tear production), and corneal sequestra. Infection of the nasolacrimal duct can result in chronic epiphora (excess tearing). Ulcerative skin disease can also result from FHV-1 infection. FHV-1 can also cause abortion in pregnant queens, usually at the sixth week of gestation, although this may be due to systemic effects of the infection rather than the virus directly.

In chronic nasal and sinus disease of cats, FHV-1 may play more of an initiating role than an ongoing cause. Infection at an early age may permanently damage nasal and sinus tissue, causing a disruption of ciliary clearance of mucus and bacteria, and predispose these cats to chronic bacterial infections.

There are several paired paranasal sinuses, including the frontal, ethmoidal, maxillary and sphenoidal sinuses. The ethmoidal sinuses are further subdivided into anterior and posterior ethmoid sinuses, the division of which is defined as the basal of the middle turbinate. In addition to the severity of disease, discussed below, sinusitis can be classified by the sinus cavity which it affects:

- Maxillary – can cause pain or pressure in the maxillary (cheek) area ("e.g.," toothache, or headache) (J01.0/J32.0)

- Frontal – can cause pain or pressure in the frontal sinus cavity (located above eyes), headache, particularly in the forehead (J01.1/J32.1)

- Ethmoidal – can cause pain or pressure pain between/behind the eyes, the sides of the upper part of the nose (the medial canthi), and headaches (J01.2/J32.2)

- Sphenoidal – can cause pain or pressure behind the eyes, but often refers to the skull vertex (top of the head), over the mastoid processes, or the back of the head.

The proximity of the brain to the sinuses makes the most dangerous complication of sinusitis, particularly involving the frontal and sphenoid sinuses, infection of the brain by the invasion of anaerobic bacteria through the bones or blood vessels. Abscesses, meningitis and other life-threatening conditions may result. In extreme cases the patient may experience mild personality changes, headache, altered consciousness, visual problems, seizures, coma and possibly death.

Sinus infection can spread through anastomosing veins or by direct extension to close structures. Orbital complications were categorized by Chandler et al. into five stages according to their severity (see table). Contiguous spread to the orbit may result in periorbital cellulitis, subperiosteal abscess, orbital cellulitis, and abscess. Orbital cellulitis can complicate acute ethmoiditis if anterior and posterior ethmoidal veins thrombophlebitis enables the spread of the infection to the lateral or orbital side of the ethmoid labyrinth. Sinusitis may extend to the central nervous system, where it may cause cavernous sinus thrombosis, retrograde meningitis, and epidural, subdural, and brain abscesses. Orbital symptoms frequently precede intracranial spread of the infection . Other complications include sinobronchitis, maxillary osteomyelitis, and frontal bone osteomyelitis. Osteomyelitis of the frontal bone often originates from a spreading thrombo-phlebitis. A periostitis of the frontal sinus causes an osteitis and a periostitis of the outer membrane, which produces a tender, puffy swelling of the forehead.

The diagnosis of these complications can be assisted by noting local tenderness and dull pain, and can be confirmed by CT and nuclear isotope scanning. The most common microbial causes are anaerobic bacteria and "S. aureus". Treatment includes performing surgical drainage and administration of antimicrobial therapy. Surgical debridement is rarely required after an extended course of parenteral antimicrobial therapy. Antibiotics should be administered for at least 6 weeks. Continuous monitoring of patients for possible intracranial complication is advised.

"Mycoplasma pneumoniae" is spread through respiratory droplet transmission. Once attached to the mucosa of a host organism, "M. pneumoniae" extracts nutrients, grows, and reproduces by binary fission. Attachment sites include the upper and lower respiratory tract, causing pharyngitis, bronchitis, and pneumonia. The infection caused by this bacterium is called atypical pneumonia because of its protracted course and lack of sputum production and wealth of extrapulmonary symptoms. Chronic "Mycoplasma" infections have been implicated in the pathogenesis of rheumatoid arthritis and other rheumatological diseases.

"Mycoplasma" atypical pneumonia can be complicated by Stevens–Johnson syndrome, autoimmune hemolytic anemia, cardiovascular diseases, encephalitis, or Guillain–Barré syndrome.

Feline viral rhinotracheitis (FVR) is an upper respiratory or pulmonary infection of cats caused by "feline herpesvirus 1", of the family "Herpesviridae". It is also commonly referred to as feline influenza, feline coryza, and feline pneumonia but, as these terms describe other very distinct collections of respiratory symptoms, they are misnomers for the condition. Viral respiratory diseases in cats can be serious, especially in catteries and kennels. Causing one-half of the respiratory diseases in cats, FVR is the most important of these diseases and is found worldwide. The other important cause of feline respiratory disease is "feline calicivirus".

FVR is very contagious and can cause severe disease, including death from pneumonia in young kittens. It can cause flat-chested kitten syndrome, but most evidence for this is anecdotal. All members of the "Felidae" family are susceptible to FVR; in fact, FHV-1 has caused a fatal encephalitis in lions in Germany.