Conjunctivitis:
Conjunctivitis, commonly known as "pink eye," is an inflammation of the conjunctiva, the transparent membrane that lines the inside of the eyelid and covers the white part of the eyeball. It is a highly common eye condition that can affect individuals of all ages, and although it can be uncomfortable, it is usually not serious.
Definition
Conjunctivitis is an inflammation of the conjunctiva, the thin, clear tissue that lies over the white part of the eye and lines the inside of the eyelid. This inflammation leads to redness, irritation, and discharge, giving the characteristic "pink" appearance of the affected eye.
Types of Conjunctivitis
Conjunctivitis is categorized based on its cause:
- Viral Conjunctivitis: Caused by viruses, often the same viruses that cause the common cold. This type is highly contagious and spreads through direct or indirect contact with infected individuals.
- Bacterial Conjunctivitis: Caused by bacterial infections such as Staphylococcus, Streptococcus, or Haemophilus. It is also contagious and often results in more discharge than viral conjunctivitis.
- Allergic Conjunctivitis: Triggered by allergens such as pollen, dust, pet dander, or mold. This type is not contagious and often occurs in individuals with other allergic conditions like hay fever or asthma.
- Chemical Conjunctivitis: Caused by exposure to irritants like smoke, chlorine in swimming pools, or chemicals.
- Irritant Conjunctivitis: Results from a foreign object or substance entering the eye, such as dust or a contact lens.
Etiology
The cause of conjunctivitis varies depending on its type:
- Viral Conjunctivitis: Commonly caused by adenoviruses, which are also responsible for respiratory infections. It may accompany cold symptoms such as a runny nose and sore throat.
- Bacterial Conjunctivitis: Caused by bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, or Haemophilus influenzae. Poor hygiene, touching the eyes with dirty hands, or sharing contaminated objects can spread the bacteria.
- Allergic Conjunctivitis: Triggered by exposure to allergens like pollen, dust mites, or pet dander. It often occurs in individuals with a predisposition to allergies.
- Chemical and Irritant Conjunctivitis: Direct exposure to chemicals or foreign bodies can irritate the conjunctiva.
Pathophysiology
- Viral Conjunctivitis: Viruses invade the conjunctival cells, leading to inflammation and immune responses. This results in increased blood flow to the conjunctiva, causing redness, swelling, and watery discharge.
- Bacterial Conjunctivitis: Bacteria multiply on the conjunctival surface, leading to an inflammatory response that produces pus or mucopurulent discharge. The body's immune system releases white blood cells to fight the infection, which contributes to the thick discharge.
- Allergic Conjunctivitis: Exposure to allergens triggers the release of histamine from mast cells in the conjunctiva, leading to inflammation, itching, and tearing.
- Chemical Conjunctivitis: Exposure to irritants causes direct damage to the conjunctiva and triggers an inflammatory response to protect the eye from further harm.
Clinical Manifestations
Viral Conjunctivitis:
- Redness in one or both eyes
- Watery or mucous discharge
- Swelling of the conjunctiva and eyelids
- Sensitivity to light (photophobia)
- Often associated with cold-like symptoms (sore throat, runny nose)
Bacterial Conjunctivitis:
- Redness in one or both eyes
- Thick, yellow, or green discharge that may cause the eyelids to stick together, especially after sleep
- Swelling of the conjunctiva and eyelids
- Mild pain or irritation
Allergic Conjunctivitis:
- Red, itchy, and watery eyes
- Swelling of the conjunctiva
- May be accompanied by other allergy symptoms (sneezing, runny nose)
- Usually affects both eyes
Chemical/Irritant Conjunctivitis:
- Redness and irritation in the affected eye(s)
- Tearing and burning sensation
- Swelling of the eyelids
- Pain or discomfort, depending on the severity of the irritant
Diagnosis
- Clinical History: Diagnosis is primarily based on the patient's symptoms, history of exposure (e.g., contact with infected individuals, allergens, or chemicals), and physical examination.
- Physical Examination: An eye examination to assess redness, discharge, and swelling. In some cases, fluorescein dye may be used to detect damage to the cornea.
- Microbiological Testing: For bacterial conjunctivitis, swabs of the discharge may be taken to identify the causative organism and guide antibiotic treatment.
- Allergy Testing: In cases of allergic conjunctivitis, allergy tests may be performed to identify specific allergens.
Treatment
Pharmacological Treatment
Viral Conjunctivitis:
- Supportive Care: No specific antiviral treatment is required. The infection is self-limiting and usually resolves within 1-2 weeks.
- Artificial Tears: To relieve discomfort and irritation.
- Topical Antihistamines/Decongestants: May be used to alleviate symptoms, though typically not necessary.
Bacterial Conjunctivitis:
- Topical Antibiotics: E.g., erythromycin ointment, ciprofloxacin, or tobramycin eye drops. Antibiotics help reduce the duration of the infection and prevent complications.
- Systemic Antibiotics: In severe cases or when conjunctivitis is part of a more generalized infection, oral antibiotics may be required.
Allergic Conjunctivitis:
- Topical Antihistamines: E.g., olopatadine or ketotifen, to reduce itching and redness.
- Mast Cell Stabilizers: E.g., cromolyn sodium, to prevent the release of histamine.
- Corticosteroid Eye Drops: In severe cases, a short course of topical corticosteroids may be used to reduce inflammation.
Chemical/Irritant Conjunctivitis:
- Irrigation: Immediate and thorough rinsing of the eye with saline or clean water to remove the chemical or foreign substance.
- Lubricant Eye Drops: To soothe the eye and prevent dryness.
- Topical Antibiotics: May be prescribed if there is a risk of secondary bacterial infection.
Non-Pharmacological Treatment
- Cold Compresses: For allergic or viral conjunctivitis, applying cold compresses can help reduce inflammation and discomfort.
- Proper Hygiene: Washing hands frequently, avoiding touching the eyes, and using clean towels can help prevent the spread of infectious conjunctivitis.
- Avoiding Allergens: For allergic conjunctivitis, minimizing exposure to known allergens is crucial in preventing symptoms.
Prevention
- Good Hygiene: Washing hands regularly and avoiding touching or rubbing the eyes can prevent the spread of viral or bacterial conjunctivitis.
- Avoid Sharing Personal Items: Towels, eye makeup, and pillowcases should not be shared to prevent cross-contamination.
- Proper Contact Lens Care: Cleaning and replacing contact lenses as recommended reduces the risk of conjunctivitis.
- Allergen Avoidance: Minimizing exposure to allergens like pollen, dust mites, and pet dander can help prevent allergic conjunctivitis.
FAQs about Conjunctivitis
How long is conjunctivitis contagious? Viral and bacterial conjunctivitis are contagious as long as symptoms persist. Typically, bacterial conjunctivitis is contagious until 24-48 hours after starting antibiotics, while viral conjunctivitis remains contagious for 1-2 weeks.
Can conjunctivitis clear up on its own? Yes, viral conjunctivitis typically resolves on its own without treatment within 1-2 weeks. Bacterial conjunctivitis may also resolve without antibiotics but is often treated to prevent complications and shorten the infection duration.
Can I wear contact lenses with conjunctivitis? No, contact lenses should not be worn during an active infection. They can worsen irritation and increase the risk of complications.
How do I know if my conjunctivitis is bacterial or viral? Bacterial conjunctivitis typically produces thick, yellow or green discharge, while viral conjunctivitis is more likely to cause watery discharge and is often associated with cold-like symptoms. A healthcare professional can confirm the diagnosis.
0 Comments