Conjunctivitis causes and treatment
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Causes of Conjunctivitis: Viral, Bacterial, Allergic, and Other Triggers
Conjunctivitis, also known as pink eye, is an inflammation of the conjunctiva—the thin membrane covering the white part of the eye and the inner eyelids. The main causes are viral infections, bacterial infections, allergies, and irritants. Viral conjunctivitis, most often caused by adenoviruses, is the most common type in adults and spreads easily through direct contact or respiratory droplets. Bacterial conjunctivitis is more common in children and is usually caused by bacteria such as Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalis, and Haemophilus influenzae. Allergic conjunctivitis is triggered by exposure to allergens like pollen and is especially prevalent during certain seasons. Other less common causes include foreign bodies, environmental irritants, and, in newborns, specific pathogens leading to neonatal conjunctivitis. Toxic conjunctivitis can also occur from long-term use of eye drops with preservatives Azari2013Jasim2024Mahoney2023+5 MORE.
Symptoms and Diagnosis of Conjunctivitis
Common symptoms of conjunctivitis include redness, itching, tearing, discharge (which may be watery or pus-like), grittiness, and eyelids sticking together, especially after sleep. Viral and allergic conjunctivitis typically present with watery discharge and itching, while bacterial conjunctivitis often causes a thicker, mucopurulent discharge and eyelids matted shut. Allergic conjunctivitis is usually accompanied by intense itching and is often bilateral. Diagnosis is based on a thorough history and physical examination, as no single symptom can definitively distinguish between viral and bacterial causes. Rapid diagnostic tests can help reduce unnecessary antibiotic use, especially in viral cases Azari2013Jasim2024Mahoney2023+4 MORE.
Treatment Strategies for Conjunctivitis
Viral Conjunctivitis Treatment
Most cases of viral conjunctivitis are self-limiting and do not require specific treatment. Supportive care, such as artificial tears, cold compresses, and maintaining good hygiene, helps relieve symptoms. Antiviral medications like acyclovir are generally not effective for adenoviral conjunctivitis. Preventing spread through handwashing and avoiding sharing personal items is important Azari2013Mahoney2023Winters2024+4 MORE.
Bacterial Conjunctivitis Treatment
Bacterial conjunctivitis often resolves on its own within 1–2 weeks, but topical antibiotics (such as erythromycin, chloramphenicol, or fusidic acid) can shorten the duration and help patients return to school or work sooner. Antibiotics are especially recommended for severe cases, contact lens wearers, and infections caused by sexually transmitted bacteria like chlamydia or gonorrhea, which may also require systemic treatment. Delayed antibiotic prescribing has been shown to be as effective as immediate prescribing in uncomplicated cases Azari2013Mahoney2023Zulfiqar2024+4 MORE.
Allergic Conjunctivitis Treatment
Allergic conjunctivitis is managed with topical antihistamines, mast cell stabilizers, or dual-acting agents. In more severe cases, short courses of topical steroids or nonsteroidal anti-inflammatory drugs (NSAIDs) may be used, but long-term steroid use requires monitoring for side effects. Oral antihistamines can also be used, but may cause dry eyes with prolonged use. Avoiding known allergens and using lubricating eye drops can help reduce symptoms Azari2013Mahoney2023Winters2024+3 MORE.
Other and Supportive Treatments
For all types of conjunctivitis, cleaning the eyes with sterile saline or cooled boiled water and using cool compresses can provide symptom relief. In cases of chronic or atypical conjunctivitis, or when there are warning signs like severe pain or vision loss, referral to an ophthalmologist is recommended. Antiseptics may be considered as alternatives to antibiotics, but can sometimes cause allergic reactions Mahoney2023Zulfiqar2024Winters2024+3 MORE.
Prevention and Special Considerations
Good personal hygiene, including frequent handwashing and avoiding touching or rubbing the eyes, is key to preventing the spread of infectious conjunctivitis. Contact lens wearers should be especially cautious and seek prompt treatment for any symptoms. Neonatal conjunctivitis requires special attention due to unique pathogens and potential complications Azari2013Mahoney2023Winters2024+2 MORE.
Conclusion
Conjunctivitis is a common eye condition with various causes, including viruses, bacteria, and allergens. Most cases are mild and resolve with supportive care, but appropriate diagnosis and targeted treatment are important to relieve symptoms, prevent complications, and reduce transmission. Antibiotics should be reserved for bacterial cases where necessary, while antihistamines and mast cell stabilizers are effective for allergic conjunctivitis. Good hygiene practices are essential for prevention and control Azari2013Jasim2024Mahoney2023+7 MORE.
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