Signs and Symptoms of Pink Eye (Conjunctivitis)
Pink eye presents differently depending on the underlying cause, but the most common presentations are viral conjunctivitis with watery discharge, photophobia, and pain; bacterial conjunctivitis with mucopurulent discharge and matted eyelids; and allergic conjunctivitis with itching as the hallmark symptom. 1, 2, 3
Viral Conjunctivitis Signs and Symptoms
Viral conjunctivitis is the most common overall cause of infectious conjunctivitis and presents with the following characteristic features: 4
- Abrupt onset, often starting unilaterally but frequently becoming sequentially bilateral 1
- Watery discharge (not purulent) 1, 3
- Photophobia (photosensitivity) indicating corneal involvement, particularly with adenoviral keratoconjunctivitis 1, 3
- Pain (rather than just irritation), suggesting significant inflammation 3
- Bulbar conjunctival injection (redness) 1
- Follicular reaction of the inferior tarsal conjunctiva 1
- Preauricular lymphadenopathy (swollen lymph node in front of the ear) 1
- Chemosis (conjunctival swelling) 1
- Eyelid swelling and erythema 1
- Petechial or subconjunctival hemorrhages 1
- Membrane or pseudomembrane formation in severe cases 1
The triad of watery discharge, photosensitivity, and pain strongly distinguishes viral from bacterial conjunctivitis. 2, 3
Bacterial Conjunctivitis Signs and Symptoms
Bacterial conjunctivitis is the second most common cause of infectious conjunctivitis and presents with: 4
- Mucopurulent or purulent discharge (thick, yellow-green) 2, 5
- Matted eyelids on waking (eyelids stuck together) 4, 5
- Lack of itching (helps differentiate from allergic causes) 4
- Conjunctival injection (redness) 5
- Absence of photophobia (unlike viral conjunctivitis) 2
- Typically unilateral initially, though can become bilateral 5
- No history of previous conjunctivitis episodes 4
Mattering and adherence of eyelids on waking, lack of itching, and absence of prior conjunctivitis history are the strongest predictors of bacterial etiology. 4
Allergic Conjunctivitis Signs and Symptoms
Allergic conjunctivitis affects up to 40% of the population and is characterized by: 4
- Itching as the most consistent and hallmark symptom 4, 6
- Watery discharge 5
- Bilateral presentation (both eyes affected) 6
- Chemosis (conjunctival swelling) 6
- Conjunctival injection (redness) 6
- Associated with history of atopy, asthma, or eczema 1
- Seasonal pattern in seasonal allergic conjunctivitis 6
Herpes Simplex Virus (HSV) Conjunctivitis
HSV conjunctivitis has distinctive features: 1
- Usually unilateral 1
- Watery discharge 1
- Mild follicular reaction 1
- Palpable preauricular lymph node 1
- Vesicular rash or ulceration of eyelids (distinctive sign) 1
- Dendritic epithelial keratitis on corneal examination 1
Varicella Zoster Virus (VZV) Conjunctivitis
VZV conjunctivitis presents with: 1
- Usually unilateral 1
- Vesicular dermatomal rash or ulceration of eyelids with severe pain (distinctive) 1
- Watery discharge 1
- Mild follicular reaction 1
- Pleomorphic or pseudodendritic epithelial keratitis 1
Red Flags Requiring Immediate Ophthalmology Referral
The following symptoms indicate serious complications and mandate urgent specialist evaluation: 2, 3, 5
- Decreased vision 2, 3, 5
- Severe pain (not just irritation) 2, 3, 5
- Corneal involvement 2, 3
- Recent ocular surgery 2, 3, 5
- Vesicular rash on eyelids or nose (suggests HSV or VZV) 2, 3, 5
- Immunocompromised state 2, 5
- Neonatal conjunctivitis (requires immediate evaluation for gonococcal or chlamydial infection) 2
- Contact lens wearer with conjunctivitis 2
Key Clinical Pitfalls
Do not assume watery discharge always means viral conjunctivitis—bacterial conjunctivitis can occasionally present atypically with watery discharge, though purulent discharge is classic. 2
Photophobia and pain indicate corneal involvement, which elevates the urgency and requires careful evaluation for keratitis. 3
Itching is the single most reliable symptom for distinguishing allergic from infectious conjunctivitis. 4, 6