A Comprehensive Guide to Allergic Conjunctivitis vs Viral Conjunctivitis

What is viral conjunctivitis?

Conjunctivitis caused by a viral strain is labeled as viral conjunctivitis. The most common cause of viral conjunctivitis is adenovirus, which accounts for 90% of the clinically presenting viral conjunctivitis. In most of the cases, it is a self-limiting condition however in some cases, topical therapy should be instituted. Allergic conjunctivitis vs viral conjunctivitis is a confusing topic, as both conditions may have almost the same presentation. However, there is a difference in treatment of allergic conjunctivitis vs viral conjunctivitis, which be discussed in the following article.

What is allergic conjunctivitis?

There is allergic conjunctivitis when the conjunctiva is exposed to allergens, triggering an allergic reaction. The most common allergens are pollens and trees. A history of allergies or allergic conditions, such as asthma or hay fever, makes people more prone to allergic conjunctivitis.

Types of conjunctivitis

types of allergic conjunctivitis

There are few types of allergic conjunctivitis. They are as followed.

  1. Acute allergic conjunctivitis: It is a common condition caused by contact with allergens such as pollens during summer or spring season.  The hallmark sign is chemosis. It will take minutes to a few hours to start. There is no specific treatment for acute allergic conjunctivitis
  2. Seasonal allergic conjunctivitis: It is the most common type and is worse during spring and summer. The most common allergens are pollens and trees.
  3. Perennial allergic conjunctivitis: It is usually present throughout the year, but the symptoms are worst during autumn and with exposure to house mites and animal dander.

Types of Viral Conjunctivitis

There includes

  1. Nonspecific acute follicular conjunctivitis: this is the most common cause of viral conjunctivitis. The disease starts with itching, watering, and photophobia in one eye, and the other eye is involved in few days.
  2. Pharyngoconjuctival fever: the symptoms in pharyngoconjunctivitis are similar to non-specific acute follicular conjunctivitis. The serotypes involved in PCF are 3,4 and 7. Keratitis is developed in 30% of the cases.
  3. Epidemic keratoconjunctivitis: It is caused by serotype 8.17 and 39. It is associated with 80% of kerato conjunctivitis.
  4. Acute hemorrhagic conjunctivitis: It is caused by entero virus and coxsackievirus. Usually resolves in 1-2 weeks.
  5. Herpes simplex virus: HSV causes follicular conjunctivitis and is usually unilateral. It occurs in primary infection.
  6. Molluscum contagiosum: it occurs in otherwise healthy children of 2-4 years of age. Chronic follicular conjunctivitis is associated with the disease.


Causes allergic conjunctivitis vs viral conjunctivitis

causes of allergic conjunctivitiscauses of viral conjunctivitis
Allergic conjunctivitis is a condition caused due to hypersensitivity reaction to certain environmental allergens. It is a type 1 allergic conjunctivitis (immediate hypersensitivity).Viral conjunctivitis is primarily caused by various types of viruses, including adenoviruses, herpes simplex viruses, and enteroviruses. These viruses can be transmitted through respiratory droplets, direct eye contact, or touching surfaces contaminated with the virus.

Symptoms Allergic Conjunctivitis Vs Viral Conjunctivitis

Viral Conjunctivitis SymptomsAllergic Conjunctivitis Symptoms
The common symptoms of viral conjunctivitis include itching, watering, and photophobia, depending upon the specific cause, it may or may not be associated with conditions such as sore throat and runny nose.
These includes acute to subacute watering and itching from eyes associated with sneezing and nasal discharge.

How do I know if my conjunctivitis is allergic?

The allergic conjunctivitis usually begins by contact with the offending allergen such as pollens, animal dander, trees etc. There might be history of the same episode. The conjunctivitis will present with itching and watering of the eyes.

Signs of allergic conjunctivitis vs viral conjunctivitis

Eyelid edema
Conjunctival hyperemia
Anterior uveitis
These includes mild papillary reaction,
chemosis and lid edema.
Bacterial vs Viral vs allergic conjunctivitis


The following tests are although not necessary and diagnosis can be made clinically, however the following tests are performed for diagnosis of viral conjunctivitis.

  • Giemsa stain
  • Nucleic acid amplification
  • Viral culture
  • Point of care immunochromatography
  • Serology

The diagnosis of allergic conjunctivitis is clinical, and no specific test is performed. However, in active eosinophilia can be demonstrated with conjunctival scrapings.


Allergic Conjunctivitis vs Viral Conjunctivitis treatment

How to treat viral conjunctivitis in adults

  • Spontaneous resolution: the viral conjunctivitis will resolve on its own in 1-3 weeks without any treatment.
  • Transmission risk reduction: it should be done by rigorously washing hands repeatedly and avoid sharing towels or clothes with others.

Best eye drops for viral conjunctivitis

  • Topical steroids: the treatment is usually with steroids however persons with keratitis should be treated with caution so that keratitis may not worsen with steroids.
  • Artificial tears: these are used for symptomatic relief; preservative free tears are highly encouraged.
  • Other drugs: topical anti histamine and vasoconstrictives can improve itching.

What are the common eye drops for allergic conjunctivitis?

Allergic conjunctivitis treatment

  • Artificial tears: These are used for mild symptoms.
  • Antihistamines: These are used for exacerbation of symptoms (emedastine, epinastin)
  • Mast cell stabilizers: They are suitable for long term use only (lodoxamide, neodocromil cromoglicate)
  • Non-steroidal anti-inflammatory cells: can provide symptomatic relief.
  • Topical steroids: are rarely used.
  • Oral antihistamines: These are indicated for severe symptoms (loratadine, diphenhydramine)


Viral conjunctivitis Home remedies

  • Viral conjunctivitis is an infective condition and a person with the disease should try to keep away from other members of the family.
  • Rubbing of the eyes should be avoided and in severe cases, cold compresses should be used.
  • A person with viral conjunctivitis should keep his belonging away such as towels, sheets, and other things touched by the infected person.
  • Regular washing of the eyes should be done.
  • A checklist or check alarm should be maintained for the regular use of medications.

Allergic conjunctivitis home remedies

  • Excessive itching of the eyes can be avoided with cold compresses.
  • In case of excess tearing and nasal discharge dehydration should be avoided with taking regular liquids and water intake should be increased.
  • Frequent sneezing can be avoided by keeping the room warm and hydrated with the help of hydration machines.
  • Rest should be taken as much as possible to boost your immunity.
  • Green tea is a natural herbal, labeled to have a beneficial role in treating allergies.
  • A good diet should be maintained especially taking a protein diet such as boiled meat or chicken broth.

Does allergic conjunctivitis need antibiotics?

No, allergic conjunctivitis does not need antibiotics. On the other hand, artificial tear, steroids and oral anti histamines are used for allergic conjunctivitis.

What is the first line treatment for allergic conjunctivitis?

The first line treatment for allergic conjunctivitis is oral anti histamines, beside that artificial tears and topical anti histamines can be added topically.


The prevention of allergic conjunctivitis lies in avoiding the offending substance so that the allergic reaction will not be triggered. If you are living in a particular area with pollens or anything you are allergic to, it is better to change your locality, if possible, for you.

Viral conjunctivitis is a contagious disease transferred from one person to another by touching the contaminated material and then touching your eyes. Avoiding sharing of such material is crucial in stopping the spread of viral conjunctivitis,


Allergic conjunctivitis has a good prognosis when and if the hypersensitivity reaction is controlled well on time. If the control is not good, then certain medications such as steroids will lead to other ocular problems like cataract, glaucoma, and corneal ulcer formation. Knowing about the time and duration of medication for allergic conjunctivitis is important.

Similarly, if viral conjunctivitis is controlled well on time has a better prognosis and the cornea will be protected from complications such as ulcers and scaring.


It is important to immediately get an advice by the health professional whenever you have watery and itchy eyes. prevention is always better then cure. Knowing your disease, its medication, and compliance is most important in dealing with relevant disease.


Will viral conjunctivitis go away?

Yes, if the disease is controlled well on time with medications, then the viral conjunctivitis will go away in couple of weeks.

Can viral conjunctivitis turn into bacterial?

The viral conjunctivitis can be superimposed with bacterial conjunctivitis, if hygiene is not maintained, however viral conjunctivitis will not turn into bacterial conjunctivitis.

How to treat viral conjunctivitis in toddlers?

Viral conjunctivitis in toddlers is treated in similar fashion as adults.

How long does allergic conjunctivitis last?

Allergic conjunctivitis will resolve on its on in a week or two.

How Is Viral Conjunctivitis Spread

The infection is spread by share fomites or towels, rubbing contagious hand on eyes and eyelids.

How Long Is Viral Conjunctivitis Contagious

The viral conjunctivitis is contagious for 1 week.


  1. American Academy of Ophthalmology. (2021). Conjunctivitis. https://www.aao.org/eye-health/diseases/what-is-conjunctivitis
  2. American College of Allergy, Asthma & Immunology. (2021). Allergic conjunctivitis. https://acaai.org/allergies/types/eye-allergies/allergic-conjunctivitis
  3. Centers for Disease Control and Prevention. (2020). Conjunctivitis (Pink Eye). https://www.cdc.gov/conjunctivitis/index.html
  4. National Eye Institute. (2021). Conjunctivitis. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/conjunctivitis-pink-eye
  5. Singh, S., Singh, U., & Pandey, A. (2011). Viral conjunctivitis: a review of literature. Indian Journal of Medical Microbiology, 29(3), 103-110. doi: 10.4103/0255-0857.83905
Dr Sadia Ayaz
Dr Sadia Ayaz

I am an ophthalmologist and eye surgeon

Articles: 47

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