Cultures are not often taken or needed as most cases resolve either with time or typical antibiotics. Swabs for bacterial culture are necessary if the history and signs suggest bacterial conjunctivitis but there is no response to topical antibiotics. Viral culture may be appropriate in epidemic case clusters.

A patch test is used to identify the causative allergen in the case where conjunctivitis is caused by allergy.

Conjunctival scrapes for cytology can be useful in detecting chlamydial and fungal infections, allergy, and dysplasia, but are rarely done because of the cost and the general lack of laboratory staff experienced in handling ocular specimens. Conjunctival incisional biopsy is occasionally done when granulomatous diseases ("e.g.", sarcoidosis) or dysplasia are suspected.

Treatment of herpes of the eye is different based on its presentation: epithelial keratitis is caused by live virus while stromal disease is an immune response and metaherpetic ulcer results from inability of the corneal epithelium to heal:

A specific clinical diagnosis of HSV as the cause of dendritic keratitis can usually be made by ophthalmologists and optometrists based on the presence of characteristic clinical features. Diagnostic testing is seldom needed because of its classic clinical features and is not useful in stromal keratitis as there is usually no live virus. Laboratory tests are indicated in complicated cases when the clinical diagnosis is uncertain and in all cases of suspected neonatal herpes infection:

- Corneal smears or impression cytology specimens can be analyzed by culture, antigen detection, or fluorescent antibody testing. Tzanck smear, i.e.Papanicolaou staining of corneal smears, show multinucleated giant cells and intranuclear inclusion bodies, however, the test is low in sensitivity and specificity.

- DNA testing is rapid, sensitive and specific. However, its high cost limits its use to research centers.

- Demonstration of HSV is possible with viral culture.

- Serologic tests may show a rising antibody titer during primary infection but are of no diagnostic assistance during recurrent episodes.

Classification can be either by cause or by extent of the inflamed area.

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.

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.

The cornerstone of diagnosis is an accurate history, and a good clinical examination of the eye, to eliminate traumatic uveitis. Ultrasonography is a useful tool, as it can detect a thickened iris, but only in the hands of an expert.

The disease incidence varies widely depending on the geographical location. The most extensive epidemiological survey on this subject has been carried out by Dharmasena et al. who analysed the number of neonates who developed neonatal conjunctivitis in England from 2000 to 2011. In addition to the incidence of this sight threatening infection they also investigated the time trends of the disease. According to them the incidence of Neonatal conjunctivitis (Ophthalmia Neonatorum) in England was 257 (95% confidence interval: 245 to 269) per 100,000 in 2011.

There is no treatment currently available. The virus generally resolves itself within a five to seven day period. The use of steroids can actually cause a corneal microbial superinfection which then requires antimicrobial therapy to eliminate.

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.

Allergy testing may reveal the specific allergens to which an individual is sensitive. Skin testing is the most common method of allergy testing. This may include a patch test to determine if a particular substance is causing the rhinitis, or an intradermal, scratch, or other test. Less commonly, the suspected allergen is dissolved and dropped onto the lower eyelid as a means of testing for allergies. This test should be done only by a physician, since it can be harmful if done improperly. In some individuals not able to undergo skin testing (as determined by the doctor), the RAST blood test may be helpful in determining specific allergen sensitivity. Peripheral eosinophilia can be seen in differential leukocyte count.

Allergy testing can either show allergies that are not actually causing symptoms or miss allergies that do cause symptoms. The intradermal allergy test is more sensitive than the skin prick test but is more often positive in people that do not have symptoms to that allergen.

Even if a person has negative skin-prick, intradermal and blood tests for allergies, he/she may still have allergic rhinitis, from a local allergy in the nose. This is called local allergic rhinitis. Specialized testing is necessary to diagnose local allergic rhinitis.

Antibiotic ointment is typically applied to the newborn's eyes within 1 hour of birth as prevention against gonococcal ophthalmia. This maybe erythromycin, tetracycline, or silver nitrate.

The diagnosis of viral meningitis is made by clinical history, physical exam, and several diagnostic tests. Most importantly, cerebrospinal fluid (CSF) is collected via lumbar puncture (also known as spinal tap). This fluid, which normally surrounds the brain and spinal cord, is then analyzed for signs of infection. CSF findings that suggest a viral cause of meningitis include an elevated white blood cell count (usually 10-100 cells/µL) with a lymphocytic predominance in combination with a normal glucose level. Increasingly, cerebrospinal fluid PCR tests have become especially useful for diagnosing viral meningitis, with an estimated sensitivity of 95-100%. Additionally, samples from the stool, urine, blood and throat can also help to identify viral meningitis.

In certain cases, a CT scan of the head should be done before a lumbar puncture such as in those with poor immune function or those with increased intracranial pressure.

If the allergen is encountered and the symptoms are mild, a cold compress can be used to provide relief.

A detailed history allows physicians to determine whether the presenting symptoms are due to an allergen or another source. Diagnostic tests such as conjunctival scrapings to look for eosinophils are helpful in determining the cause of the allergic response. Antihistamines, medication that stabilizes mast cells, and NSAIDs are safe and usually effective. Corticosteroids are reserved for more severe cases of ocular allergy disease, and their use should be monitored by an eye care physician due to possible side-effects. When an allergen is identified, the person should avoid the allergen as much as possible.

Horses that suffer from this disease can never be considered cured, although they can be managed by careful use of the therapy described above, and fast detection of new flare-ups. If the disease is not properly treated, it will eventually lead to blindness.

The likelihood of the infection being spread can be reduced through behaviors such as avoiding touching an active outbreak site, washing hands frequently while the outbreak is occurring, not sharing items that come in contact with the mouth, and not coming into close contact with others (by avoiding kissing, oral sex, or contact sports).

Because the onset of an infection is difficult to predict, lasts a short period of time and heals rapidly, it is difficult to conduct research on cold sores. Though famciclovir improves lesion healing time, it is not effective in preventing lesions; valaciclovir and a mixture of acyclovir and hydrocortisone are similarly useful in treating outbreaks but may also help prevent them.

Acyclovir and valacyclovir by mouth are effective in preventing recurrent herpes labialis if taken prior to the onset of any symptoms or exposure to any triggers. Evidence does not support L-lysine.

One way to prevent allergic rhinitis is to wear a respirator or mask when near potential allergens.

Growing up on a farm and having multiple brothers and or sisters decreases the risk.

Acute hemorrhagic conjunctivitis (AHC) (also spelled acute haemorrhagic conjunctivitis) is a derivative of the highly contagious conjunctivitis virus, otherwise known as pink eye. Symptoms include excessively red, swollen eyes as well as subconjuntival hemorrhaging. Currently, there is no known treatment and patients are required to merely endure the symptoms while the virus runs its five- to seven-day course. While it was first identified in Ghana, the virus has now been seen in China, India, Egypt, Cuba, Singapore, Taiwan, Japan, Pakistan, Thailand, and the United States.

Safe and effective adenovirus vaccines were developed for adenovirus serotypes 4 and 7, but were available only for preventing ARD among US military recruits, and production stopped in 1996. Strict attention to good infection-control practices is effective for stopping transmission in hospitals of adenovirus-associated disease, such as epidemic keratoconjunctivitis. Maintaining adequate levels of chlorination is necessary for preventing swimming pool-associated outbreaks of adenovirus conjunctivitis.

Docosanol, a saturated fatty alcohol, is a safe and effective topical application that has been approved by the United States Food and Drug Administration for herpes labialis in adults with properly functioning immune systems. It is comparable in effectiveness to prescription topical antiviral agents. Due to its mechanism of action, there is little risk of drug resistance. The duration of symptoms can be shortened a bit if an antiviral, anesthetic, zinc oxide or zinc sulfate cream is applied soon after it starts.

Effective antiviral medications include acyclovir and penciclovir, which can speed healing by as much as 10%. Famciclovir or valacyclovir, taken in pill form, can be effective using a single day, high-dose application and is more cost effective and convenient than the traditional treatment of lower doses for 5–7 days.

A vaccine is available in the UK and Europe, however in laboratory tests it is not possible to distinguish between antibodies produced as a result of vaccination and those produced in response to infection with the virus. Management also plays an important part in the prevention of EVA.

The basic method for control of the conjunctivitis includes proper hygiene and care for the affected eye. If the conjunctivitis is found to be caused by "H. aegyptius" Biogroup III then prompt antibiotic treatment preferably with rifampin has been shown to prevent progression to BPF. If the infected person resides in Brazil, it is mandatory that the infection is reported to the health authority so that a proper investigation of the contacts can be completed. This investigation will help to determine the probable source of the infection.

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.

It has been proposed that viral meningitis might lead to inflammatory injury of the vertebral artery wall.

The Meningitis Research Foundation is conducting a study to see if new genomic techniques can the speed, accuracy and cost of diagnosing meningitis in children in the UK. The research team will develop a new method to be used for the diagnosis of meningitis, analysing the genetic material of microorganisms found in CSF (cerebrospinal fluid). The new method will first be developed using CSF samples where the microorganism is known, but then will be applied to CSF samples where the microorganism is unknown (estimated at around 40%) to try and identify a cause.