Conjunctivitis: Types, Duration & Medicines

What Is Conjunctivitis?

Conjunctivitis is inflammation of the conjunctiva — the thin clear membrane covering the white of the eye and inner eyelids. When inflamed, its tiny vessels dilate, making the eye look red with discharge and irritation. In Thai it is loosely called "ta daeng" (red eye), but medically conjunctivitis spans several types whose causes and treatments differ greatly — infection, allergy, and irritation.

The good news: most cases do not permanently affect vision and resolve on their own. Knowing the type helps you pick the right medicine, recover faster, and avoid spreading it.

Types of Conjunctivitis

There are 4 main types by cause:

📖 Read more: Full guide to the allergic type (itch-dominant, not contagious) — Eye Allergy: Symptoms, Treatment & Medicine · The infective type (epidemic pink eye) — Pink Eye: Causes, Contagion & Recovery Time

Conjunctivitis Symptoms

• Redness across or in part of the white of the eye
• Unusual discharge — its character is the best type clue (clear = viral/allergic, thick green-yellow = bacterial)
• Gritty, burning sensation like sand in the eye
• Itching — intense itch points to allergy
• Watering and swollen lids
• Lids stuck together on waking from dried discharge (usually bacterial)

Symptoms that are not simple conjunctivitis: severe pain, blurred vision, marked light sensitivity, or halos around lights — suspect conditions needing urgent care such as acute glaucoma, keratitis, or uveitis.

How Long Conjunctivitis Lasts

• Viral — usually self-resolves over about 2-3 weeks (StatPearls) (severe adenovirus can take longer). Symptoms usually peak around days 3-5, then ease
• Bacterial — usually self-limiting over about 7-10 days; antibiotics can shorten it (not a guaranteed 2-5 day cure)
• Allergic — usually improves once away from triggers and on treatment, though severe types (VKC/AKC) can last weeks, and it recurs with re-exposure
• Everyday irritants (smoke, dust, chlorine) — usually settle after rinsing and removing the irritant · ⚠️ A strong chemical in the eye (e.g. bleach or oven cleaner) is an emergency — rinse the eye with clean water for at least 20 minutes (NHS first-aid guidance), then get to an emergency department immediately (call 1669 for an ambulance in Thailand), continuing to rinse on the way and taking the chemical's container if you can. Do not wait and watch.

⚠️ All types: NHS advises seeing a doctor if symptoms have not cleared up within 7 days, they worsen, or it keeps recurring — and sooner if there are warning signs (severe pain, blurred vision).

Which Medicines to Use

Key principle: match the medicine to the type, not the redness

Adenoviral — no specific antiviral

Supportive care: artificial tears for comfort, cold compresses, gentle discharge cleaning — antibiotics do not help viral cases and should not be overused. ⚠️ If herpes simplex (HSV) or zoster eye infection is suspected — blisters around the eye, marked pain, blurred vision, or one-sided redness with a rash — it needs specific antiviral treatment and an urgent ophthalmologist.

Bacterial — antibiotic drops/ointment

A pharmacist or doctor selects the right agent; use it as directed; it can shorten the illness.

Allergic — start with avoidance and topical therapy

StatPearls describes a stepwise approach: (1) avoid the allergen + artificial tears/cold compress → (2) antihistamine / mast-cell-stabilizer eye drops (e.g., olopatadine, ketotifen) as the mainstay when symptoms are mainly ocular → (3) oral antihistamines added for more severe or nasal-accompanied cases (as advised by a pharmacist) — always consult a pharmacist first.

All types — one shared rule

Never self-prescribe steroid eye drops — the wrong use can worsen infection, and prolonged use risks glaucoma/cataracts. Ophthalmologist supervision only.

Self-Care for Faster Recovery

• Clean discharge properly — clean cotton with cooled boiled water, wipe inner to outer corner, one pad per wipe
• Compress — cold for allergic/viral types to ease swelling · warm when discharge is thick to loosen it
• Artificial tears as often as needed to flush germs/allergens
• Wash hands often and don't rub — prevents spread and protects the other eye
• Pause contact lenses until fully healed; replace lenses/case afterwards
• Skip eye makeup and discard products used during infection
• Separate towels and pillowcases, washing them frequently while ill

Is It Dangerous? When to See a Doctor

Most conjunctivitis is not dangerous and does not permanently affect vision, but see a doctor immediately with any of these:

• ❗ Severe eye pain or deep aching in the eyeball
• ❗ Blurred vision that doesn't clear with blinking
• ❗ Marked light sensitivity — unable to keep eyes open in light
• ❗ Any newborn with discharge/red eyes — always needs a doctor; risk of serious infection
• ❗ Contact-lens wearers with a red eye — urgent regardless of pain (NHS); remove lenses and get same-day assessment, corneal ulcer risk
• ❗ Weakened immunity (poorly controlled diabetes, immunosuppressants) with eye infection signs
• ❗ Very swollen, hot, red lids + fever — suspect orbital cellulitis

Not an emergency, but see a doctor: if symptoms have not cleared up within 7 days or it recurs unusually often, book an appointment (NHS).