Reasoning GP · Algorithm · 1-page summary

Itchy eye

For: adults and children with itchy eyes, including neonates with discharge, in hours or OOH. Not for: a painful red eye without itch (use the red eye algorithm) or an eye injury (foreign body algorithm); ongoing care is in the allergic conjunctivitis, blepharitis and dry eye protocols.

Reviewed October 2026 · next review April 2027

College of Optometrists CMGsRCOphth 2021BSACI rhinitisBASHH chlamydiaLocal Eye formulary

Core rule: itch usually means allergy — but pain, photophobia, reduced vision or a painful red eye in a contact-lens wearer means it is not simple allergy: same-day ophthalmology, and never start steroid drops.

0Stop — call 999 now

Acute angle-closure glaucoma — severe pain, haloes, cloudy cornea, nausea/vomiting, headache, visual disturbance (also in a patient on steroid drops) → 999 / emergency ophthalmology.
Severe orbital or facial infection with systemic illness, neurological symptoms or rapidly progressive swelling → 999
Anaphylaxis with airway or systemic compromise → 999
Do not palpate the globe for pressure, give IV acetazolamide from primary care, or delay transfer.

1Triage by pattern

Pattern	Means → action
Itch, bilateral, watery	Allergy more likely → blocks 3–5
Burning, gritty	Fluctuating vision → dry eye or blepharitis
Pain, photophobia, ↓ vision	Or marked unilateral redness → do not assume allergy → block 2
Contact lens + pain	Painful red eye = emergency until keratitis excluded → block 2
Neonate <28 days	Any purulent discharge → block 2

2Screen — same-day ophthalmology

Reduced or changed acuity, moderate/severe pain, photophobia, ciliary flush (uveitis) → Same-day
Contact-lens wearer with painful red eye → lens out now, no patch, no steroid → Same-day emergency. Corneal haze, opacity, ulcer or staining → Same-day
Dendritic staining (herpes simplex), V1 rash or Hutchinson's sign (zoster), new diplopia or restricted movements → Same-day
Neonate with purulent discharge → Same-day paediatrics/ophthalmology; gonococcal and chlamydial swabs.
VKC or AKC with photophobia, reduced vision or corneal staining → Same-day; otherwise VKC → Within 1 week

3Assess

☐ Acuity each eye ☐ Redness pattern, discharge ☐ Lid margins ☐ Cornea + fluorescein ☐ Pupils, eye movements ☐ Evert upper lid: child with severe chronic itch, lens wearer with lens intolerance ☐ Lenses, drops, cosmetics, atopy

No tests for typical seasonal allergy; specific IgE only if it changes management; swab if purulent, neonatal or chronic follicular (chlamydia PCR, sexual history). No slit lamp and any doubt → refer.

4Classify — only if blocks 0–2 are negative

Allergic conjunctivitis — bilateral itch, watery, seasonal or perennial, atopy, rhinitis → block 5.
Blepharitis / meibomian gland dysfunction — lid-margin itch, morning crusting → lid hygiene.
Dry eye — burning, grit, blur clearing on blinking → lubricants.
Contact dermatoconjunctivitis — periorbital eczema from drop preservative (BAK) or cosmetics → stop agent, preservative-free drops.
Giant papillary conjunctivitis — lens wearer, itch on removal, papillae → lenses out, optometry.
Uncertain — unilateral, chronic follicular or not responding → reconsider and refer.

5Treat today — only these

Allergic: topical antihistamine or mast-cell stabiliser per local formulary (sodium cromoglicate, ketotifen, azelastine, olopatadine); mast-cell stabilisers before the season. Cold compresses, no rubbing, no lenses while active. Loratadine 10 mg or cetirizine 10 mg OD if rhinitis.
Blepharitis: warm compress → lid massage → lid scrub, long term. Antibiotic ointment may be considered for selected anterior disease; doxycycline usually after specialist advice (not in pregnancy, breastfeeding or under 12).
Dry eye: lubricants, preservative-free if frequent use or ocular-surface disease; ointment at night if severe.
No topical steroid from primary care; do not renew ophthalmology steroids without review. Doses: NICE/SPC, BNF, local formulary.

6Refer non-urgently

Within 1 week ophthalmology: persistent AKC; GPC not settling; follicular conjunctivitis not settling after 4 weeks; recurrent severe allergy needing steroid.
Routine optometry/ophthalmology: dry eye or blepharitis despite an adequate trial. Minor eye conditions service (same or next day) for mild–moderate cases without red flags.
Allergy clinic: rhinoconjunctivitis uncontrolled on antihistamine + nasal steroid, occupational allergy, immunotherapy. Sexual health: suspected chlamydial conjunctivitis.

7Never reassure by

"It itches" when there is pain, photophobia or reduced vision.
A contact-lens wearer's painful red eye labelled allergy or conjunctivitis.
No giant papillae when the upper lid was not everted.
A cornea that looks clear by direct light alone.
An absent Hutchinson's sign — it does not exclude eye involvement.
Failed antihistamines met with more antihistamine — think dry eye, preservative allergy, chlamydia, VKC.

8Safety-net — say it, then document it

999 “Severe eye pain with haloes, headache or vomiting — call 999.” Same day “If the eye becomes painful, light hurts, your vision changes, or a lens-wearing eye turns red and painful (take the lens out), get same-day eye assessment.” Same week review if not controlled after 2–4 weeks of treatment, and reconsider the diagnosis.

✓Safe to leave primary care only if — all five, documented

Acuity each eye normal No pain, photophobia or block 0–2 feature Cornea checked; lid everted if needed Lenses, drops and cosmetics reviewed Safety-net and review route given

Summary of the full Reasoning GP itchy eye algorithm, which holds the examination technique, allergen advice, blepharitis and dry eye detail and evidence. Sources: College of Optometrists Clinical Management Guidelines; RCOphth Commissioning Guide for Medical Ophthalmology 2021; BSACI rhinitis guideline 2017; BASHH chlamydia guideline; NICE neonatal infection guidance; NICE TA369; local Eye formulary. Clinical reference — follow the local eye pathway and check doses: NICE/SPC, BNF.