Conjunctivitis: Causes, Symptoms, and Treatment of Pink Eye

Conjunctivitis is a common eye condition that can affect both adults and children. It occurs for various reasons, such as viral or bacterial infections, allergies, or exposure to environmental irritants. While typically a mild condition, conjunctivitis is easily treatable. In this article, we’ll cover in detail the causes, symptoms, diagnosis, treatment, and prevention of conjunctivitis.

What Is the Conjunctiva?

The conjunctiva is the thin, transparent membrane that covers the white part of the eye and lines the inner surface of the eyelids. It consists of a delicate layer of cells that protect the eye from foreign substances and external irritants.

What Is Conjunctivitis?

Conjunctivitis, commonly known as "pink eye," occurs when the conjunctiva becomes inflamed. This inflammation causes the eye to appear red or pink, swollen, and irritated. It may also result in discharge from the eye. In some cases, conjunctivitis can be highly contagious.

The inflammation causes tiny blood vessels in the conjunctiva to become more visible, which contributes to the red or pink appearance. The condition can last from 1 to 4 weeks or longer.

What Causes Conjunctivitis?

The causes of conjunctivitis vary depending on the type. Some cases are due to allergies, while others are caused by infections or exposure to chemicals. The main types include:

Types of Conjunctivitis

Allergic Conjunctivitis

This type, also known as allergic conjunctivitis, often affects individuals with seasonal allergies. It results from exposure to allergens that trigger an immune response in the eyes.

A more severe form, called giant papillary conjunctivitis, occurs due to chronic presence of a foreign object in the eye. It's common in people who wear hard or soft contact lenses that are not replaced frequently or in those with artificial eyes.

Bacterial Conjunctivitis

Bacterial conjunctivitis is an infection caused by bacteria such as Staphylococcus or Streptococcus from the skin or respiratory system. It can result from exposure to insects, physical contact, touching the eyes with unclean hands, or using contaminated makeup or facial products.

Wearing or sharing contact lenses that are improperly cleaned or shared with others can also lead to bacterial conjunctivitis.

Viral Conjunctivitis

Viral conjunctivitis is most often caused by viruses associated with the common cold. It can develop after exposure to coughs or sneezes from someone with a respiratory infection.

Viruses can also spread through mucous membranes that connect the lungs, throat, nose, tear ducts, and conjunctiva. Because tears drain into the nasal passage, forceful nose blowing may transfer the virus from the respiratory tract to the eyes.

Chemical Conjunctivitis

This type results from exposure to irritants such as air pollution, chlorine in swimming pools, or harmful chemicals.

What Are the Symptoms of Conjunctivitis?

Symptoms can vary depending on the type and severity of the condition, but generally include:

• Excessive tearing
   
• Green or white eye discharge
   
• Burning or itching sensation
   
• Redness in the eye
   
• Blurred vision
   
• Light sensitivity
   
• Swollen lymph nodes (commonly in viral infections)
   

Early signs may also include:

• Redness in the white of the eye or inner eyelid
   
• Swelling and congestion of the conjunctiva
   
• Thick discharge that may crust over the eyelashes, especially after sleep
   
• Itchiness in both eyes

How Is Conjunctivitis Diagnosed?

Eye doctors usually diagnose conjunctivitis by asking questions about symptoms such as itching and the type of discharge, and whether the patient has cold symptoms, hay fever, or asthma.

Diagnosis may also include:

• Vision test to check if vision is affected
   
• Examination of the external eye tissues with a bright light and magnification
   
• Internal eye exam to rule out other eye issues
   
• Conjunctival swab, especially if the condition is chronic or unresponsive to treatment

How Is Conjunctivitis Treated?

Treatment depends on the type and cause of conjunctivitis:

Allergic Conjunctivitis

Treated using antihistamines to reduce the allergic reaction. Over-the-counter options include loratadine and diphenhydramine. Antihistamine or anti-inflammatory eye drops may also help relieve symptoms.

Bacterial Conjunctivitis

Antibiotic eye drops or ointments are the standard treatment. Eye drops are usually preferred for adults, while ointments may be easier to apply in children.

Symptoms often improve within a few days of starting antibiotics, but the full course must be completed to prevent recurrence.

Viral Conjunctivitis

Most cases are mild and clear up on their own within 7 to 10 days. Warm compresses can help soothe discomfort.

In rare cases caused by herpes simplex or varicella-zoster viruses, antiviral medication is required. These medications are prescribed only for specific viral infections.

Home Remedies for Conjunctivitis

Several home treatments can ease symptoms, including:

• Warm compresses
   
• Over-the-counter artificial tears
   
• Avoiding contact lens use until the eye fully heals

Conjunctivitis in Children

Newborns can develop a severe form of bacterial conjunctivitis called ophthalmia neonatorum, caused by exposure to chlamydia or gonorrhea during birth. This is a medical emergency that can lead to permanent eye damage if untreated.

For this reason, antibiotic eye ointment is routinely applied to newborns as a preventive measure.

Is Conjunctivitis Contagious?

Yes. Viral and bacterial forms are highly contagious and can spread through:

• Personal contact (e.g., shaking hands then touching the eyes)
   
• Respiratory droplets from sneezing or coughing
   
• Touching contaminated surfaces then the eyes
   

Infectious conjunctivitis is usually contagious during the symptomatic period, so patients should stay home while symptomatic.

How to Prevent Conjunctivitis

Practicing good hygiene is the best prevention:

• Avoid touching eyes with unwashed hands
   
• Wash hands frequently with soap and water
   
• Use clean tissues and towels
   
• Do not share eye makeup or facial products
   
• Wash pillowcases regularly
   
• Follow proper contact lens hygiene
   
• Avoid contact lens use during active infection

FAQs

Can conjunctivitis heal on its own?
Yes, some forms—especially viral—can resolve without medical treatment. However, appropriate medications can speed recovery depending on the cause.

How long does conjunctivitis last?
The duration depends on the type, but most cases improve within one to two weeks.