Conjunctivitis: Types, Causes, Symptoms and Treatment

2. Allergic Conjunctivitis

• Seasonal Allergic Conjunctivitis (SAC) 
• Perennial Allergic Conjunctivitis (PAC) 
• Vernal Keratoconjunctivitis (VKC) 
• Atopic Keratoconjunctivitis (AKC)

3. Chemical or Toxic Conjunctivitis
4. Immune-mediated Conjunctivitis (Giant Papillary Conjunctivitis - GPC)
5. Neonatal Conjunctivitis (Ophthalmia Neonatorum)

Explanation of Conjunctivitis

1. Infectious Conjunctivitis

This type is caused by microorganisms such as bacteria, viruses, or chlamydia.

A. Bacterial Conjunctivitis

Bacterial conjunctivitis is an infection of the conjunctiva, the clear tissue covering the white part of the eye and inner eyelids, caused by bacteria. It leads to redness, swelling, eye irritation, and a thick yellow or green discharge. It is contagious and commonly spreads through direct contact or contaminated surfaces.

Key Features:

• Thick, purulent (pus-like) discharge.
• Eyelids may stick together, especially after waking up.
• Redness and discomfort.
• Often unilateral initially but can spread to the other eye.

B. Viral Conjunctivitis

Viral conjunctivitis, also known as pink eye, is an eye infection caused by viruses, often associated with the common cold or respiratory infections. It leads to redness, watery discharge, itching, and a gritty sensation in the eyes. Highly contagious, it spreads through contact with infected surfaces, respiratory droplets, or direct eye contact. While there is no specific antiviral treatment, symptoms usually resolve on their own within 1-2 weeks. Maintaining good hygiene, such as frequent handwashing and avoiding eye touching, helps prevent its spread.

Key Features:

• Watery discharge and redness.
• Preauricular lymphadenopathy (swelling of lymph nodes near the ears).
• Highly contagious and often spreads in epidemics.
• Associated symptoms may include fever, sore throat, or respiratory infection.

c. Chlamydial Conjunctivitis

• Causes: Caused by Chlamydia trachomatis. There are two forms:
  • Inclusion Conjunctivitis: Common in sexually active adults and caused by serotypes D-K (Serotypes D-K of Chlamydia trachomatis are strains associated with sexually transmitted infections and certain neonatal conditions. These serotypes primarily cause urogenital infections, presenting as urethritis, cervicitis, or pelvic inflammatory disease in adults. In neonates, they can lead to conjunctivitis or pneumonia through vertical transmission during childbirth.).
  • Trachoma: Caused by serotypes A-C (Serotypes A-C refer to specific strains of Chlamydia trachomatis, a bacterium responsible for causing trachoma, a chronic eye infection. These serotypes primarily affect the conjunctiva and are a leading cause of preventable blindness worldwide, particularly in developing regions with poor sanitation. Infection occurs through direct contact with infected individuals, contaminated surfaces, or flies that transmit the bacteria.) and is associated with poor hygiene and overcrowding.
• Key Features:
  • Follicular conjunctivitis (small, round lymphoid tissue on the conjunctiva).
  • Mucopurulent discharge.
  • Chronic infection can lead to corneal scarring and blindness (especially in trachoma).

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2. Allergic Conjunctivitis

This type occurs due to hypersensitivity reactions to allergens such as pollen, dust, or animal dander. It is typically bilateral (both eyes).

a. Seasonal Allergic Conjunctivitis (SAC)

• Associated with specific seasons, particularly spring and summer.
• Triggered by outdoor allergens like pollen.
• Symptoms include intense itching, tearing, and redness.

b. Perennial Allergic Conjunctivitis (PAC)

• Occurs year-round.
• Triggered by indoor allergens such as dust mites, pet dander, or mold.
• Symptoms are similar to SAC but milder and persistent.

c. Vernal Keratoconjunctivitis (VKC)

Vernal keratoconjunctivitis (VKC) is a chronic, severe allergic eye condition that primarily affects children and young adults, especially males, in warm climates. It is characterized by intense itching, redness, and photophobia (sensitivity to light), often accompanied by a thick, ropy discharge. VKC involves inflammation of the conjunctiva and cornea and can cause giant papillae on the upper eyelid or a shield-shaped corneal ulcer in severe cases. It is typically associated with a history of other allergic conditions, such as asthma or eczema.

• A more severe, chronic form of allergic conjunctivitis.
• Common in children, especially boys, in warm climates.
• Key features include:
  • Intense itching and photophobia.
  • Large cobblestone-like papillae on the upper eyelid.
  • Stringy, mucus-like discharge.
  • Can lead to corneal complications (e.g., shield ulcers).

d. Atopic Keratoconjunctivitis (AKC)

Atopic keratoconjunctivitis (AKC) is a chronic, bilateral allergic eye condition commonly associated with atopic dermatitis. It typically affects adults and can persist year-round. Symptoms include intense itching, redness, watery discharge, and sensitivity to light, often accompanied by eyelid skin changes like thickening or scaling. Prolonged inflammation can lead to serious complications, such as corneal scarring, keratoconus, or vision loss. 

• A rare, chronic condition linked to atopic dermatitis (eczema).
• Symptoms include severe itching, redness, and a thickened, scaly eyelid margin.
• Chronic inflammation can cause corneal scarring and vision loss.

Difference Between VKC & AKC

POINTS	VKC	AKC
Age Group	Common in children and young adults	Typically affects adults
Associated Conditions	Often associated with asthma and seasonal allergies	Strongly linked with atopic dermatitis (eczema)
Climate	More prevalent in warm, dry climates	Can occur year-round, not climate-dependent
Gender	More common in males	More common in males, but can also affect females
Symptoms	Intense itching, redness, photophobia, thick discharge	Itching, redness, watery discharge, eyelid skin changes
Conjunctival Findings	Giant papillae on the upper eyelid	More severe eyelid inflammation and thickening
Corneal Involvement	May cause shield ulcers in severe cases	Can lead to corneal scarring and keratoconus
Chronicity	Usually self-limiting, often resolves in adulthood	Chronic condition, can persist into adulthood
Treatment	Antihistamines, mast cell stabilizers, steroids	Management of atopic dermatitis, antihistamines, immunosuppressants
Complications	Corneal ulcers, vision impairment (rare)	Corneal scarring, keratoconus, permanent vision loss

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3. Chemical or Toxic Conjunctivitis

This type occurs due to exposure to chemical irritants or toxic substances. Common causes include:

• Chlorinated water (e.g., swimming pools).
• Airborne chemicals or pollutants.
• Contact with cosmetics or cleaning products.

Key Features:

• Acute redness, burning, and discomfort immediately after exposure.
• Resolves once the irritant is removed, but severe exposure may lead to corneal damage.

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4. Immune-mediated Conjunctivitis

a. Giant Papillary Conjunctivitis (GPC)

• Occurs due to mechanical irritation and immune response, often from prolonged use of contact lenses or ocular prostheses.


• Key Features:
  • Large papillae (>0.3 mm) on the tarsal conjunctiva (underside of the eyelid).
  • Itching, lens discomfort, and excessive mucus production.

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5. Neonatal Conjunctivitis (Ophthalmia Neonatorum)

This type affects newborns within the first month of life. Common causes include:

• Neisseria gonorrhoeae: Severe purulent discharge; can lead to corneal perforation.
• Chlamydia trachomatis: Mucopurulent discharge, less severe than gonococcal conjunctivitis.
• HSV: Vesicular lesions around the eyes.

Key Features:

• Redness, discharge, and eyelid swelling in the newborn.
• Requires immediate treatment to prevent complications such as blindness.

Causes of Conjunctivitis 

Infectious Causes

Bacteria: 

• Staphylococcus aureus, 
• Streptococcus pneumoniae, 
• Haemophilus influenzae, 
• Neisseria gonorrhoeae. 

Viruses: 

• Adenovirus, 
• Herpes simplex virus (HSV), 
• Enterovirus. 

Chlamydia: Chlamydia trachomatis (Types D-K and A-C in trachoma).

Non-infectious Causes

• Allergens (pollen, dust, animal dander). 
• Chemical irritants (chlorine, smoke, cosmetics). 
• Foreign bodies in the eye. 
• Systemic diseases (e.g., Stevens-Johnson syndrome, Sjögren's syndrome).

Signs and Symptoms

General Features

• Redness of the eye (hyperemia). 
• Tearing or watery discharge. 
• Foreign body sensation. 
• Photophobia (sensitivity to light). 
• Itching (prominent in allergic conjunctivitis). 
• Swelling of the eyelids (Chemosis).

Specific Features

Bacterial: Thick, purulent discharge; eyelids stuck together, especially in the morning. 

Viral: Watery discharge, preauricular lymphadenopathy, follicular conjunctiva. 

Allergic: Intense itching, bilateral involvement, stringy discharge. 

Chlamydial: Mucopurulent discharge, follicular conjunctiva, corneal pannus (trachoma). 

Chemical: Acute redness, burning, and discomfort immediately after exposure.

Diagnosis of conjunctivitis

Clinical Examination

History: Onset, duration, associated symptoms (e.g., itching, discharge, trauma, or exposure). 

Slit-lamp examination: Evaluation of conjunctiva, cornea, and discharge.

Diagnostic Tests

1. Conjunctival Swab or Scrapings

• Gram stain for bacterial infection. 
• Giemsa stain for Chlamydia. 
• Viral culture or PCR for adenovirus/HSV.

2. Tear Film Analysis

• Schirmer's test (if dryness is suspected). 
• Conjunctival impression cytology.

3. Other Tests

• Rapid antigen tests (for adenoviral conjunctivitis). 
• Fluorescein staining (for corneal involvement).

Investigations

• Microbiological Tests: Culture and sensitivity of conjunctival swabs. 
• Serological Tests: If systemic infection (e.g., Chlamydia, gonorrhea) is suspected. 
• Allergy Testing: Skin prick or IgE levels for allergic conjunctivitis. 
• Polymerase Chain Reaction (PCR): High sensitivity for viral and chlamydial infections.

Treatment of Conjunctivitis

1. Infectious Conjunctivitis

Bacterial:

• Topical Antibiotics: Tobramycin, Chloramphenicol, Ciprofloxacin, Moxifloxacin. 
• Severe Cases: Systemic antibiotics for Neisseria gonorrhoeae or Chlamydia.

Viral:

• Supportive care with cold compresses. 
• Topical Lubricants: Artificial tears. 
• Antiviral Medications: Acyclovir for HSV conjunctivitis.

Chlamydial:

• Oral Azithromycin (single dose of 1g) or Doxycycline (100 mg twice daily for 7 days).

2. Allergic Conjunctivitis

• Topical Antihistamines: Olopatadine, Ketotifen. 
• Mast Cell Stabilizers: Sodium cromoglycate, Lodoxamide. 
• Topical Steroids: Loteprednol (short-term use in severe cases). 
• Oral Antihistamines: Cetirizine, Loratadine.

3. Chemical/Toxic Conjunctivitis

• Immediate irrigation with saline or Ringer’s lactate. 
• Topical lubricants and antibiotics (to prevent secondary infection).

Management

• Educate patients about proper hygiene (e.g., handwashing, avoiding eye rubbing). Discontinue contact lens use during active conjunctivitis. 
• Use of sunglasses to reduce photophobia. 
• Avoid sharing personal items like towels.

Complications

Infectious Conjunctivitis

• Corneal ulceration (bacterial and viral cases). 
• Scarring in trachoma.

Allergic Conjunctivitis

• Keratopathy. 
• Vision loss (rare).

Neonatal Conjunctivitis

• Orbital cellulitis. 
• Corneal perforation.

Chemical Conjunctivitis

• Permanent corneal damage. 
• Symblepharon formation.

This comprehensive outline on conjunctivitis will help students understand key clinical aspects and prepare them for both theoretical and practical exams.