Eye Allergies Or Pink Eye Conjunctivitis? How To Tell

Eye Allergies Or Pink Eye Conjunctivitis? How To Tell

Allergies vs conjunctivitis can be tough to tell apart. They are two common causes of red eyes that can lead to discomfort and irritation. Though both conditions share similar symptoms, it is essential to understand how the eye doctor can tell them apart.

Allergies Vs Conjunctivitis: Appearance

As expected both eye allergies and conjunctivitis can appear or look very similar. Let’s take a closer look at how this can be confusing.


Both allergic reactions in the eye and conjunctivitis can cause redness in the eyes. In the case of eye allergies, the increased blood flow to the affected area results in the dilation of blood vessels, which leads to the redness. In conjunctivitis, whether it is bacterial or viral, the inflammation of the conjunctiva also increases blood flow and redness.

Eyelid Swelling

Mild eyelid swelling is common in both eye allergies and conjunctivitis. For both conditions, the swelling occurs due to the body’s immune response to either the allergen or the infection. 

Eyelid swelling may also be a result of patients rubbing or touching their eyes. This is common because patients often have eye irritation and they rub their eyes which unfortunately only makes it worse.

Discharge, But Bacterial Conjunctivitis Can Have Yellow Discharge

Both eye allergies and conjunctivitis can produce discharge, but the appearance and consistency may vary. Here’s is a breakdown of what you may see on the surface of the eye:

Eye allergies: clear, thin, watery discharge

Viral conjunctivitis: clear, water discharge, but can be slighter thicker

Bacterial conjunctivitis: yellow-green discharge and often this eye discharge can be very sticky making it hard to open the eye

However, there is a spectrum for discharge. And telling the difference between viral conjunctivitis and eye allergies just from discharge can be tough. However, if you see yellow-green discharge that is purulent and thick, this is more likely to be bacterial pink eye.

Allergies Vs Conjunctivitis: Eye Symptoms

Even though the underlying cause of allergies or conjunctivitis may be different, the eye symptoms of allergic conjunctivitis can be very similar to that of eye allergies.

Pain With Blinking In Both

Both allergies and conjunctivitis can cause pain when blinking. In the case of allergic conjunctivitis, the immune system releases chemicals called histamines due to exposure to allergens, which leads to itching, redness, and pain. Mast cells in the conjunctiva become activated, causing inflammation of the inside of the eyelids. However, the pain is usually mild and less severe than in viral conjunctivitis.

In viral conjunctivitis, the pain can be more severe because it’s caused by a viral infection that leads to swelling, inflammation, and in some cases, a discharge that may cause the eyes to stick together.

Blurry Vision More Likely in Viral Conjunctivitis

While both conditions can cause some degree of vision disturbance, blurry vision is more commonly associated with viral conjunctivitis. In viral conjunctivitis, the infected eye often produces a discharge that can temporarily blur vision, requiring frequent blinking or cleaning.

On the other hand, with allergic conjunctivitis, vision tends to not be as affected, with the exception of cases where the eyes are excessively watery or have been rubbed intensively due to itching.

Itching In Both

Both eye allergies and viral conjunctivitis can cause itching, which can be uncomfortable and even severe in some cases. The itching in both conditions can result in further irritation if the person rubs their eyes.

In allergic conjunctivitis, itching is driven by histamine release, while in viral conjunctivitis, it is triggered by the immune system’s response to the viral infection.

Symptoms Duration Is Different

Pink Eye Symptom Duration

The symptoms of pink eye are usually self limited since most pink eye is viral. If the type of pink eye is bacterial then symptoms will only resolve once an antibiotic eye drop has been used to treat the infectious pink eye.

Viral conjunctivitis usually lasts 2 to 3 weeks, with varying levels of severity during this period. The symptoms may worsen or improve periodically but will not subside until the virus has run its course. While over-the-counter eye drops and medications can provide some symptomatic relief, there is no cure for viral conjunctivitis, and the immune system must eliminate the virus on its own.

Eye Allergy Symptom Duration

In allergic conjunctivitis, symptoms are typically associated with allergen exposure and tend to subside as soon as the person is no longer exposed to the allergen. Patients may notice that certain allergy triggers will make their itchy eyes worse. 

Anti-allergy medications, such as antihistamines, can help alleviate the symptoms by blocking histamine release.

Allergies Vs Conjunctivitis: Affected Eye

The sequence or order in which the eyes get affected can help the eye doctor or healthcare provider to tell the difference between the two. 

Pink Eye – Usually One Eye Affected Then the Other

Pink eye, also known as conjunctivitis, is the inflammation of the conjunctiva, a thin transparent membrane that covers the white part of the eye and the inner eyelids. There are three main types of conjunctivitis: viral, bacterial, and allergic. Viral and bacterial conjunctivitis usually begin in one eye and often spread to the other eye within days. 

Eye Allergies – Usually Both Eyes Affected Equally

Eye allergies, also known as allergic conjunctivitis, occur when the body reacts to an allergen, resulting in an immune response in the eyes. Unlike viral and bacterial conjunctivitis, eye allergies are not contagious and typically affect both eyes equally. Common allergens that trigger eye allergies include pollen, dust, animal dander, and certain medications.

Allergies Vs Conjunctivitis: Associated Symptoms

An accurate diagnosis can be reached by also taking a proper medical history. There are subtle differences in the associated symptoms of both of these eye problems.

Conjunctivitis Associated With Viral Infection

One of the main causes of pink eye is a viral infection. Patients may experience symptoms such as:

  • Redness in the eyes
  • Watery discharge
  • Itching or burning sensation
  • Light sensitivity
  • Crusting of the eyelids
  • Enlarged lymph node

It is important to note that an enlarged lymph node is extremely unlikely in the case of eye allergies. If you can feel an enlarged lymph node, maybe in your neck or in front of your ear, this is more likely to be a viral conjunctivitis. This is because an enlarged lymph node is a a sign of the body’s response to a viral infection 

Other associated symptoms with viral conjunctivitis include a sore throat and runny nose. These symptoms often occur before the onset of conjunctivitis, suggesting a link between the viral infection and pink eye.

Eye Allergies Associated With Atopy

Eye allergies, also known as allergic conjunctivitis, can be classified into two categories: seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC). Both types are caused by an overreaction of the immune system to common allergens, such as pollen, mold, dust mites, or pet dander. 

Patients with seasonal allergies are more likely to have redness of the eyes during allergy season. Also, allergy testing can be very helpful to figure out which specific allergen is causing the eye allergy symptoms. 

Common associated symptoms of eye allergies include:

  • Itchy, red, and watery eyes
  • Swollen eyelids
  • Nasal congestion
  • Sneezing
  • Runny nose
  • Eczema

In contrast to pink eye, there is typically no enlarged lymph node present in eye allergies. Additionally, patients with allergic conjunctivitis may also suffer from other conditions related to allergies, such as eczema. This skin condition can cause itching, redness, and dryness of the skin, further indicating that allergies may be the cause of the eye symptoms.

Conjunctivitis In Contact Lens Wearers

In patients who wear contact lenses, giant papillary conjunctivitis (GPC) can also occur. This can mimic pink eye symptoms. 

Typically the first step here is to take a break from contact lenses can help to improve this. Patients may also need to change contact lens brands to help avoid another episode. GPC is a type of allergic conjunctivitis, but it is not necessarily associated with hay fever.

Allergies Vs Conjunctivitis: Diagnosis And Treatment


The best way to know what is causing your eye redness, watering of the eyes, and eye pain is to get a professional evaluation from an eye doctor. As you can see from the above similarities it can be very hard tell the types of pink eye from eye allergies.

Treatment Is Different

Although eye allergies and conjunctivitis may share common symptoms, their treatment is different. 

Treating Viral Pink Eye

Viral Pink Eye typically has no specific treatment as it will go away on its own after a few days, just like a common cold. To help alleviate symptoms such as itchiness, discomfort, and swelling, you can use cool compresses on the affected eye and lubricating eye drops or artificial tears.

Treating Bacterial Pink Eye

Bacterial Conjunctivitis requires antibiotic treatment to clear the infection. Antibiotic eye drops are prescription medications. Patients should notice an improvement within a few days. If you do not see an improvement then it is important to follow up. 

It is also important to be honest about your medical history, including your sexual history. Some infectious forms of pink eye like the infectious conjunctivitis caused by gonorrhea needs special treatment. If proper treatment is not given for this, patients can lose vision.

Treating Eye Allergies 

There are many different treatments for eye allergies. The first line of defense is to avoid the allergen causing the reaction.

If avoidance of the allergen is not possible, here are some treatment options. 

  • Oral Antihistamines: Over-the-counter (OTC) medications like Loratadine, Cetirizine, or Fexofenadine can help relieve general allergy symptoms, including hay fever and eye allergies. 

  • Antihistamine Eye Drops: These eye drops help relieve itchiness and redness in the eyes by targeting histamine receptors in the ocular tissues. An example is Olopatadine.

  • Mast Cell Stabilizers: Medications like Cromolyn or Lodoxamide work by preventing the release of histamine from mast cells, the cells involved in allergic reactions. These eye drops can be used as a preventative measure for those with recurring eye allergies.

  • Nonsteroidal Anti-inflammatory Eye Drops: These help reduce eye inflammation and itching. Examples include Ketorolac and Diclofenac.

  • Steroid Eye Drops: In severe cases, an eye doctor may prescribe corticosteroid eye drops to quickly reduce inflammation. However, these should be used with caution and under the supervision of an ophthalmologist.

  • See An Allergist: For patients with chronic or severe eye allergies, an allergist can help figure out the most appropriate treatment plan. In addition to oral medications that are over the counter, you may also want to consider seeing an allergist. An allergy doctor can discuss the use of immunotherapy (allergy shots) or allergen-specific sublingual immunotherapy (SLIT) tablets.

Allergies Vs Conjunctivitis: Transmission

Conjunctivitis Is Contagious

Both viral and bacterial conjunctivitis are highly contagious. Both of these eye infections can spread easily through direct contact with an infected individual’s eye secretions or contaminated objects. 

It’s essential to be aware that if an individual has been in close contact with someone who has pink eye, it’s more likely that they will develop an infectious form of pink eye themselves.

Viral conjunctivitis is commonly caused by adenoviruses and is often accompanied by cold or flu symptoms. The likelihood of contracting this type of conjunctivitis increases if there has been contact with others suffering from it in shared spaces like schools, offices, or households.

On the other hand, bacterial conjunctivitis is caused by bacteria such as Staphylococcus aureus and Streptococcus pneumoniae. This form of pink eye can lead to a more severe eye infection if left untreated. Transmission occurs in a similar manner to viral conjunctivitis, requiring only brief contact with contaminated objects or infected individuals.

Eye Allergies Are Not Contagious

Allergic pink eye or allergic conjunctivitis differs from infectious forms in that it is caused by an allergic reaction to substances like pollen, dander, or dust mites. This type of conjunctivitis is not contagious, as it stems from an individual’s immune response rather than a viral or bacterial infection. Therefore, it’s not possible to transmit eye allergies to another person.

Allergic pink eye can occur seasonally, often coinciding with increased pollen counts during certain times of the year. It can also be triggered by pet dander, dust, or other allergens present in the individual’s environment.

Allergies Vs Conjunctivitis: Summary

Eye allergies and conjunctivitis are conditions that cause red, irritated eyes, but they have different causes and different treatments. Their symptoms can be similar since they can lead to redness, itching, eye swelling, and eye discharge. However, discharge types can vary; eye allergies typically cause a clear, watery discharge, while bacterial conjunctivitis results in a yellow-green, sticky discharge. 

Pain when blinking and itching are common in both, but viral conjunctivitis can sometimes cause more severe pain and blurry vision. The duration of symptoms differs, with viral conjunctivitis lasting 2 to 3 weeks and allergic conjunctivitis symptoms subsiding once the allergen is removed. Finally, while both viral and bacterial conjunctivitis are contagious, spreading through direct contact. However, eye allergies are not contagious as they are caused by individual reactions to allergens.

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