From the Guidelines
Pink eye, or conjunctivitis, can be bilateral in approximately 30-50% of cases, though this varies by cause, with some types like allergic conjunctivitis being almost always bilateral from onset 1.
Key Points to Consider
- The frequency of bilateral presentation varies significantly depending on the underlying cause of conjunctivitis.
- Viral conjunctivitis, particularly that caused by adenovirus, is most likely to affect both eyes, typically starting in one eye and spreading to the other within 24-48 hours.
- Bacterial conjunctivitis often begins unilaterally but can become bilateral as bacteria transfer from one eye to the other.
- Allergic conjunctivitis is almost always bilateral from onset because the allergic reaction affects both eyes simultaneously.
Preventing Spread and Diagnostic Considerations
- To prevent the spread of conjunctivitis between eyes, patients should use separate towels and washcloths for each eye, wash hands frequently, avoid touching or rubbing eyes, and apply any prescribed medications carefully to avoid cross-contamination.
- The bilateral nature of pink eye is important diagnostically, as certain causes like herpes simplex virus typically remain unilateral, while bilateral presentation often suggests viral, allergic, or advanced bacterial infection 1.
Evidence Summary
The most recent and highest quality studies, such as those published in 2024 1, provide insights into the clinical signs, associated/predisposing factors, natural history, and potential sequelae of different types of conjunctivitis, highlighting the variability in bilateral presentation among them.
From the Research
Bilateral Pink Eye
- The frequency of bilateral pink eye is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
- However, the studies suggest that conjunctivitis, which is commonly referred to as pink eye, can be caused by various factors such as viruses, bacteria, or allergies 2, 3, 4, 5, 6.
- The prevalence of viral and bacterial conjunctivitis varies between children and adults, with bacterial conjunctivitis being more common in children and viral conjunctivitis being more common in adults 6.
- Some studies suggest that certain symptoms and signs, such as pharyngitis, preauricular lymphadenopathy, and contact with another person with red eye, are associated with a higher likelihood of viral conjunctivitis, while others, such as mucopurulent discharge and otitis media, are associated with a higher likelihood of bacterial conjunctivitis 6.
- However, no single symptom or sign can differentiate between viral and bacterial conjunctivitis with high certainty 6.
Types of Conjunctivitis
- Viral conjunctivitis is the most common overall cause of infectious conjunctivitis and usually does not require treatment 2.
- Bacterial conjunctivitis is the second most common cause of infectious conjunctivitis, with most uncomplicated cases resolving in 1 to 2 weeks 2.
- Allergic conjunctivitis is encountered in up to 40% of the population, but only a small proportion of these individuals seek medical help 2.
Treatment and Management
- Treatment for viral conjunctivitis is supportive, and may include artificial tears, cold compresses, and antihistamine eye drops 3.
- Topical antibiotics are effective in treating bacterial conjunctivitis, and can decrease the duration of the infection and allow for an earlier return to school or work 2, 4.
- Topical antihistamines with mast cell-stabilizing activity are the treatment of choice for allergic conjunctivitis 3.