Pink Eye vs. Herpes: Understanding the Differences

Conjunctivitis (Pink Eye) vs. Herpes Eye Infections

Both cause red, irritated eyes but differ in etiology, presentation, and urgency.

Conjunctivitis (Pink Eye)

• Causes: Viral (adenovirus — most common), bacterial (Staph, Strep, H. flu), allergic, irritant.
• Symptoms: Diffuse injection, watery/mucopurulent discharge, itching (allergic), gritty sensation, crusting on waking.
• Course: Viral: 7–14 days, self-limited. Bacterial: improves in 2–5 days with antibiotics.
• Contagious: Highly (viral/bacterial).

Herpes Simplex Keratitis (HSV)

• Cause: HSV-1 reactivation (rarely HSV-2).
• Symptoms: Unilateral pain, photophobia, blurred vision, tearing, foreign body sensation. Dendritic ulcer on fluorescein staining (pathognomonic).
• Complications: Stromal keratitis (immune-mediated), scarring, neovascularization, vision loss.
• Recurrent: Lifelong latency in trigeminal ganglion.

Herpes Zoster Ophthalmicus (HZO)

• Cause: VZV reactivation in ophthalmic division of CN V.
• Symptoms: Dermatomal rash (forehead, scalp, eyelid), severe pain, conjunctivitis, keratitis, uveitis, cranial nerve palsies.
• Hutchinson's sign: Vesicles on nasal tip → high risk of ocular involvement.

Key Differences

Feature	Conjunctivitis	Herpes (HSV/HZO)
Pain	Mild discomfort	Moderate-severe
Vision	Usually normal	Often blurred
Photophobia	Mild/absent	Marked
Discharge	Watery/purulent	Watery
Laterality	Often bilateral	Almost always unilateral
Corneal involvement	Rare	Common (dendritic ulcer)
Treatment	Supportive / topical antibiotics	Oral + topical antivirals (acyclovir, valacyclovir); steroids for stromal disease (specialist only)
Urgency	Routine	Ophthalmology referral within 24–48 hrs

When to Seek Immediate Care

• Eye pain + blurred vision + photophobia
• Contact lens wearer with red eye
• Suspected HZO (rash in V1 distribution)
• Neonate with conjunctivitis (ophthalmia neonatorum)

Herpes eye disease is vision-threatening. Never use topical steroids without ophthalmology guidance.