Conjunctivitis: Causes, symptoms and treatment

Conjunctivitis, commonly referred to as pink eye or red eye, is an inflammation of the conjunctiva, the thin, transparent membrane that covers the white part of the eye (sclera) and lines the inner surface of the eyelids. It is a widespread condition that affects individuals of all ages, from infants to the elderly. While conjunctivitis is often mild and resolves without treatment, it can also be highly contagious and cause significant discomfort, making it essential to understand its various aspects.

Types of conjunctivitis

Conjunctivitis can be broadly categorized into several types based on its cause and characteristics.

a. Viral conjunctivitis

Viral conjunctivitis is the most common type and is typically caused by the same viruses responsible for the common cold, such as adenovirus. It is highly contagious and often spreads through direct contact with infected individuals or contaminated surfaces. Viral conjunctivitis tends to resolve on its own within one to two weeks, although symptoms may persist for a longer duration in some cases.

b. Bacterial conjunctivitis

Bacterial conjunctivitis is caused by bacterial infection, commonly strains of Staphylococcus aureus, Streptococcus pneumoniae, or Haemophilus influenzae. It can occur as a primary infection or secondary to an upper respiratory tract infection. Bacterial conjunctivitis is also highly contagious and may lead to more severe symptoms than viral conjunctivitis. Antibiotic eye drops or ointments are often prescribed to treat bacterial conjunctivitis and reduce the risk of complications.

c. Allergic conjunctivitis

Allergic conjunctivitis is triggered by allergens such as pollen, dust mites, pet dander, or certain chemicals. It is characterized by itching, redness, and swelling of the eyes, along with watery discharge. Allergic conjunctivitis can be seasonal or perennial, depending on the presence of allergens, and often coexists with other allergic conditions such as hay fever or asthma. Antihistamine eye drops and avoidance of allergens are the mainstays of treatment for allergic conjunctivitis.

d. Giant papillary conjunctivitis (GPC)

Giant papillary conjunctivitis is a type of allergic conjunctivitis characterized by the formation of large, raised bumps or papillae on the inner surface of the upper eyelids. It is commonly associated with the prolonged use of contact lenses or ocular prostheses. GPC can cause discomfort, foreign body sensation, and blurred vision. Treatment involves discontinuing contact lens wear, using lubricating eye drops, and sometimes steroid eye drops to reduce inflammation.

e. Chemical conjunctivitis

Chemical conjunctivitis results from exposure to irritating or toxic substances such as chlorine, smoke, or household chemicals. It can cause immediate redness, burning, and watering of the eyes and may lead to corneal injury if not promptly treated. Management includes rinsing the eyes with copious amounts of water and seeking medical attention if symptoms persist or worsen.

Causes of conjunctivitis

Conjunctivitis, or pink eye, can have various causes, depending on the type of conjunctivitis present.

a. Viral conjunctivitis

• Adenoviruses: Most cases of viral conjunctivitis are caused by adenoviruses, particularly types 3, 4, and 7. Adenoviral conjunctivitis often occurs in epidemics, especially in crowded environments such as schools, daycare centers, and swimming pools. It can spread through direct contact with infected individuals, respiratory droplets, or contaminated surfaces.
• Herpes Simplex Virus (HSV) and Varicella-Zoster Virus (VZV): In some cases, viral conjunctivitis can be caused by herpes simplex virus (HSV) or varicella-zoster virus (VZV), particularly in individuals with a history of cold sores or shingles. These viruses can lead to more severe forms of conjunctivitis with potential complications, such as keratitis.

b. Bacterial conjunctivitis

Bacterial conjunctivitis is typically caused by bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. These bacteria can colonize the conjunctiva, leading to infection. Bacterial conjunctivitis can be spread through direct contact with infected ocular secretions, contaminated hands, or shared items like towels or makeup.

c. Allergic conjunctivitis

Allergic conjunctivitis occurs due to an allergic reaction to various allergens, including pollen, dust mites, pet dander, mold spores, and certain chemicals. When exposed to allergens, the immune system releases histamine and other inflammatory substances, triggering the characteristic symptoms of allergic conjunctivitis. Allergic conjunctivitis is not contagious and typically affects individuals with a history of allergies or allergic conditions like hay fever or asthma.

d. Giant papillary conjunctivitis (GPC)

Giant papillary conjunctivitis (GPC) is primarily caused by mechanical irritation from foreign bodies, such as contact lenses, ocular prostheses, or sutures. Prolonged contact lens wear, improper lens hygiene, and the presence of allergens or debris on contact lenses can lead to GPC. Mechanical friction against the conjunctiva triggers an immune response, leading to inflammation and the formation of papillae on the inner surface of the eyelids.

e. Chemical conjunctivitis

Chemical conjunctivitis results from exposure to irritating or toxic substances, such as chlorine, smoke, industrial chemicals, or household cleaning products. Direct contact with these substances can cause immediate irritation, inflammation, and damage to the conjunctiva and cornea. Chemical conjunctivitis is not contagious and typically occurs due to accidental exposure or occupational hazards.

Symptoms of conjunctivitis

Conjunctivitis presents with a variety of symptoms that can vary depending on the underlying cause of the inflammation.

a. Common symptoms

1. Redness: One of the hallmark signs of conjunctivitis is redness of the whites of the eyes (sclera) and the inner lining of the eyelids. This redness is often widespread and may give the eyes a pink or bloodshot appearance.
2. Itching: Many individuals with conjunctivitis experience itching or irritation in one or both eyes. This sensation can range from mild to severe and may lead to frequent rubbing of the eyes.
3. Watery eyes (Epiphora): Conjunctivitis often causes increased tearing or watery discharge from the eyes. This discharge may be clear or slightly cloudy and can make the eyelids feel sticky or crusty, especially upon waking in the morning.
4. Grittiness or foreign body sensation: Some people with conjunctivitis report feeling as though there is something gritty or foreign in their eyes, even when there isn’t. This sensation can be uncomfortable and may worsen with blinking or eye movement.
5. Swelling: Inflammation of the conjunctiva can lead to swelling of the eyelids and the surrounding tissue, causing the eyes to appear puffy or swollen. Swelling may be more noticeable in severe cases or when the conjunctivitis is accompanied by other conditions such as allergies.
6. Sensitivity to light (Photophobia): Conjunctivitis can cause increased sensitivity to light, making it uncomfortable to be in bright or sunny environments. Individuals with photophobia may prefer to stay indoors or wear sunglasses when exposed to sunlight.
7. Crusting of eyelids: Bacterial or viral conjunctivitis can lead to the formation of crusts or discharge along the edges of the eyelids, particularly after sleep. These crusts may be yellowish, greenish, or clear and can cause the eyelids to stick together.
8. Blurred vision: In some cases, conjunctivitis may cause temporary blurred vision, particularly if there is significant swelling or discharge obstructing the visual axis. Blurred vision typically improves with treatment and resolution of the underlying inflammation.

b. Symptoms depending on the type of conjunctivitis

1. In viral conjunctivitis, symptoms typically develop gradually and may be accompanied by other signs of a viral infection, such as sore throat, cough, or fever.
2. Bacterial conjunctivitis often presents with more pronounced discharge, which may be thick and yellow or green in color.
3. Allergic conjunctivitis is characterized by intense itching, along with clear, watery discharge, and may be associated with other allergic symptoms such as sneezing or nasal congestion.
4. Giant papillary conjunctivitis can cause significant discomfort, with symptoms worsening during contact lens wear.
5. Chemical conjunctivitis typically presents with acute redness and burning sensation following exposure to the offending substance.

Stages of conjunctivitis

Conjunctivitis, commonly known as pink eye, can progress through several stages, each characterized by specific changes in symptoms and severity. The stages of conjunctivitis may vary depending on the underlying cause and individual factors.

a. Onset stage

• The onset stage marks the beginning of conjunctivitis and is characterized by the sudden appearance of symptoms.
• Symptoms may include redness of the eyes, itching or burning sensation, tearing or watery discharge, and mild swelling of the eyelids.
• Individuals may notice increased discomfort or irritation in one or both eyes, prompting them to seek medical attention.

b. Acute stage

• The acute stage represents the peak of inflammation and symptom severity.
• Redness of the eyes intensifies, becoming more pronounced and widespread.
• Itching, burning, or foreign body sensation may worsen, leading to increased discomfort and urge to rub the eyes.
• Watery discharge may increase, causing the eyelids to feel sticky or crusty, especially upon waking in the morning.
• Swelling of the eyelids and surrounding tissue may become more noticeable, contributing to a puffy or swollen appearance.
• Sensitivity to light (photophobia) may develop or worsen, making it uncomfortable to be in bright or sunny environments.

c. Subacute stage

• The subacute stage occurs as the acute inflammation begins to resolve, and symptoms gradually improve.
• Redness of the eyes may start to diminish, although some residual pinkness or discoloration may persist.
• Itching, burning, or foreign body sensation may decrease in intensity, providing relief to affected individuals.
• Watery discharge may lessen, and crusts or sticky eyelids may become less prominent.
• Swelling of the eyelids may begin to subside, resulting in a reduction in puffiness or swelling.
• Sensitivity to light may improve, allowing individuals to tolerate bright environments more comfortably.

d. Resolution stage

• The resolution stage marks the final phase of conjunctivitis, during which symptoms continue to fade away.
• Redness of the eyes fades further, returning to the normal appearance or baseline color.
• Itching, burning, or foreign body sensation resolves completely, providing relief from discomfort.
• Watery discharge disappears entirely, and eyelids become free of crusts or stickiness.
• Swelling of the eyelids resolves completely, restoring a normal contour to the eye area.
• Sensitivity to light resolves, allowing individuals to tolerate bright environments without discomfort.

Prevention of conjunctivitis

Preventing conjunctivitis involves adopting various measures to reduce the risk of infection or irritation to the eyes. While conjunctivitis can have different causes, including viruses, bacteria, allergies, and irritants, implementing preventive strategies can help minimize the likelihood of developing this condition.

a. Practice good hygiene

• Wash hands frequently: Thoroughly wash your hands with soap and water for at least 20 seconds, especially before touching your eyes, face, or contact lenses.
• Avoid rubbing eyes: Refrain from touching or rubbing your eyes, as this can transfer infectious agents or irritants from your hands to your eyes, increasing the risk of conjunctivitis.
• Use clean towels and linens: Use clean towels, pillowcases, and washcloths to avoid transferring bacteria or viruses to your eyes.

b. Avoid sharing personal items

• Avoid sharing eye cosmetics: Do not share eye makeup, such as mascara, eyeliner, or eye shadow, as these items can harbor bacteria or viruses that may cause conjunctivitis.
• Use personal towels and linens: Use your towels, pillowcases, and other personal items to prevent the spread of infectious agents from others.

c. Practice proper contact lens hygiene

• Wash hands before handling lenses: Always wash your hands with soap and water before inserting or removing contact lenses to reduce the risk of bacterial contamination.
• Clean and disinfect lenses: Follow proper contact lens care guidelines, including cleaning, disinfecting, and storing lenses as directed by your eye care professional.
• Replace lenses as recommended: Replace contact lenses and lens cases as recommended by your eye care provider to prevent bacterial buildup and reduce the risk of infection.

d. Avoid contact with infected individuals

• Limit close contact: Avoid close contact with individuals who have conjunctivitis or symptoms of an eye infection to prevent the spread of infectious agents.
• Practice respiratory hygiene: Encourage infected individuals to cover their mouth and nose when coughing or sneezing to prevent respiratory droplets from reaching your eyes.

e. Protect eyes from irritants

• Wear protective eyewear: When engaging in activities that may expose your eyes to irritants or foreign objects, such as swimming, yard work, or construction, wear protective eyewear to prevent injury or irritation.
• Avoid smoke and chemicals: Minimize exposure to smoke, fumes, chemicals, and other irritants that can cause inflammation or irritation to the eyes.

f. Manage allergies

• Identify and avoid allergens: If you have allergies that trigger allergic conjunctivitis, such as pollen, dust mites, or pet dander, take steps to minimize exposure to allergens by keeping windows closed, using air purifiers, and avoiding outdoor activities during peak pollen times.
• Use allergy medications: Take allergy medications, such as antihistamines or nasal corticosteroids, as prescribed by your healthcare provider to alleviate allergy symptoms and reduce the risk of allergic conjunctivitis.

g. Maintain a healthy lifestyle

• Boost immune system: Maintain a healthy immune system by eating a balanced diet, getting regular exercise, managing stress, and getting enough sleep to help your body fight off infections effectively.
• Stay hydrated: Drink plenty of water to stay hydrated, which helps maintain the health and lubrication of your eyes.

Diagnosis of conjunctivitis

Diagnosing conjunctivitis involves a comprehensive evaluation of the patient’s medical history, symptoms, and a thorough eye examination. The diagnostic process aims to identify the underlying cause of conjunctivitis, which can vary depending on factors such as the patient’s age, symptoms, and risk factors.

a. Medical history

The healthcare provider begins by gathering information about the patient’s medical history, including any pre-existing eye conditions, allergies, recent illnesses, exposure to infectious agents, or use of contact lenses or ocular prostheses.

b. Symptom assessment

The patient’s symptoms are carefully evaluated, including the duration and severity of redness, itching, discharge, swelling, sensitivity to light, and any associated systemic symptoms such as fever or respiratory symptoms.

c. Visual examination

A visual examination of the eyes is conducted to assess the external appearance and internal structures of the eye. This may involve the use of specialized instruments such as a slit lamp biomicroscope, which provides a magnified view of the eye.

d. Evaluation of conjunctiva

The conjunctiva, the thin, transparent membrane that covers the white part of the eye and lines the inner surface of the eyelids, is carefully examined for signs of inflammation, such as redness, swelling, discharge, or papillae (raised bumps).

e. Differentiation of types

Based on the appearance of the conjunctiva and other clinical findings, the healthcare provider differentiates between the various types of conjunctivitis, including viral, bacterial, allergic, or other less common causes such as chemical or irritant-induced conjunctivitis.

f. Laboratory tests

In some cases, additional laboratory tests may be performed to confirm the diagnosis or identify the causative agent of conjunctivitis. These tests may include conjunctival swabs for microbiological culture and sensitivity testing, polymerase chain reaction (PCR) testing for viral or bacterial DNA, or allergy testing for allergic conjunctivitis.

g. Differential diagnosis

Conjunctivitis can mimic other eye conditions such as dry eye syndrome, blepharitis, uveitis, or keratitis. A thorough differential diagnosis is conducted to rule out other potential causes of ocular inflammation and determine the most appropriate course of treatment.

h. Evaluation of complications

In severe or atypical cases of conjunctivitis, further evaluation may be necessary to assess for complications such as corneal involvement, preseptal or orbital cellulitis, or systemic spread of infection. Imaging studies or consultation with specialists may be required in such cases.

i. Patient education

Throughout the diagnostic process, the healthcare provider educates the patient about the nature of conjunctivitis, its potential causes, preventive measures, and treatment options. Patient compliance and understanding are essential for successful management and resolution of conjunctivitis.

Treatment of conjunctivitis

The treatment of conjunctivitis depends on the underlying cause of the inflammation. While some cases of conjunctivitis may resolve on their own without specific treatment, others may require medical intervention to alleviate symptoms, prevent complications, and promote healing.

a. Viral conjunctivitis

• Viral conjunctivitis typically resolves on its own within one to two weeks without specific treatment. However, supportive care and symptom management may help alleviate discomfort.
• Use cold compresses: Apply cold compresses to the affected eye(s) several times a day to reduce inflammation, soothe itching, and alleviate discomfort.
• Lubricating eye drops: Over-the-counter lubricating eye drops or artificial tears can help moisturize the eyes and relieve dryness caused by viral conjunctivitis.
• Avoiding contact lenses: Temporarily discontinue wearing contact lenses until symptoms resolve to prevent further irritation or complications.

b. Bacterial conjunctivitis

• Antibiotic eye drops or ointments: Topical antibiotic medications, such as erythromycin, bacitracin, or polymyxin B/trimethoprim, may be prescribed to treat bacterial conjunctivitis and prevent bacterial growth.
• Follow the prescribed regimen: Use antibiotic eye drops or ointments as directed by your healthcare provider, typically applying them several times a day for a specified duration (usually 5-7 days).
• Warm compresses: Applying warm compresses to the eyes can help alleviate discomfort and promote drainage of any discharge.

c. Allergic conjunctivitis

• Antihistamine eye drops: Over-the-counter or prescription antihistamine eye drops, such as ketotifen (Zaditor) or olopatadine (Patanol), can help block the allergic response and relieve itching, redness, and swelling associated with allergic conjunctivitis.
• Mast cell stabilizers: Prescription eye drops containing mast cell stabilizers, such as nedocromil (Alocril) or cromolyn (Crolom), can prevent the release of histamine and other inflammatory mediators, reducing allergic symptoms.
• Avoid allergens: Minimize exposure to known allergens, such as pollen, dust mites, pet dander, or certain chemicals, to prevent allergic reactions and minimize symptom recurrence.

d. Giant papillary conjunctivitis (GPC)

• Discontinuation of contact lens wear: Temporarily discontinue wearing contact lenses until symptoms of GPC resolve to prevent further irritation and inflammation.
• Lubricating eye drops: Use lubricating eye drops or artificial tears to alleviate dryness and discomfort associated with GPC.
• Steroid eye drops: In severe or persistent cases of GPC, your healthcare provider may prescribe short-term use of steroid eye drops to reduce inflammation and alleviate symptoms.

e. Chemical conjunctivitis

• Rinse with water: If chemical exposure occurs, immediately rinse the affected eye(s) with copious amounts of water for at least 15 minutes to flush out the irritant and prevent further damage.
• Seek medical attention: If symptoms persist or worsen after rinsing, seek prompt medical attention from an eye care professional for further evaluation and treatment.

Conclusion

Conjunctivitis is a common ocular condition characterized by inflammation or infection of the conjunctiva. While most cases of conjunctivitis resolve spontaneously or with appropriate treatment, complications such as corneal involvement or chronic inflammation may occur if left untreated. Prompt evaluation by an eye care professional is essential for accurate diagnosis and tailored management of conjunctivitis to achieve optimal outcomes and prevent potential complications.