Itchy eyes

Itchy eyes (ocular pruritus) is the urge to rub the eyes or eyelids. Allergy is the commonest cause, with blepharitis and dry eye also frequent.

Mechanisms. Mast cell degranulation and histamine release stimulate conjunctival nerve endings. Chronic forms involve T cell mediated inflammation and eosinophils.

Classification. Seasonal and perennial allergic conjunctivitis (mild, common), vernal keratoconjunctivitis (young males, spring and summer, tarsal papillae and shield ulcers), atopic keratoconjunctivitis (atopic dermatitis, adults, severe, chronic), giant papillary conjunctivitis (contact lens, prosthesis, sutures), contact dermatoconjunctivitis (drops, cosmetics), and non-allergic causes.

Key distinctions. Itch is the defining symptom of allergy. Itch with stringy mucus, large cobblestone papillae and photophobia suggests vernal keratoconjunctivitis. Itch with lid thickening, scales and lash crusting suggests blepharitis. Itch with a sore red eye and discharge suggests infection.

History. Onset, seasonality, triggers (pollen, dust, animals, cosmetics, contact lenses, topical drops), bilateral or unilateral, itch severity, tearing, watery or ropy discharge, redness, photophobia, grittiness, vision change, nasal symptoms, atopic history (eczema, asthma, hay fever), family history, previous treatment, use of steroid drops, and rubbing.

Drug history. Topical preservatives (benzalkonium chloride), neomycin and aminoglycoside drops, glaucoma drops (brimonidine, apraclonidine), antivirals, and systemic drugs causing eye irritation.

Examination. Visual acuity, lids (oedema, erythema, scaling, collarettes, lash loss, eczema), conjunctiva (papillae, follicles, chemosis, injection), tarsal conjunctiva (cobblestone papillae, Horner Trantas dots at the limbus), cornea (punctate staining, shield ulcer, plaque, keratoconus, neovascularisation), anterior chamber, and preauricular nodes. Examination of the skin and nose.

Red flags

• Reduced vision, corneal ulcer, plaque or infiltrate
• Severe pain or photophobia
• Contact lens wearer with pain
• Unilateral symptoms with discharge and preauricular node (infection)
• Neonate with discharge
• Eyelid lesions, non-healing lesion or lash loss with a nodule (malignancy)
• Steroid use with raised intraocular pressure or cataract
• Keratoconus or progressive corneal thinning (from rubbing)

Special groups. Children: vernal keratoconjunctivitis, and atopic disease; discourage rubbing. Pregnancy: avoid oral antihistamines in the first trimester when possible and use topical mast cell stabilisers. Older adults: atopic keratoconjunctivitis and blepharitis. Region specific: vernal keratoconjunctivitis is common in warm dry climates of Africa and the Middle East.

Allergic and atopic

• Seasonal and perennial allergic conjunctivitis
• Vernal keratoconjunctivitis, atopic keratoconjunctivitis
• Giant papillary conjunctivitis (contact lens, prosthesis, exposed sutures)
• Contact dermatoconjunctivitis (cosmetics, nickel, drops), eyelid eczema, atopic dermatitis

Lid and surface

• Anterior and posterior blepharitis (staphylococcal, seborrhoeic, Demodex, meibomian gland dysfunction), rosacea
• Dry eye disease, contact lens intolerance
• Floppy eyelid syndrome

Infective

• Viral, bacterial and chlamydial conjunctivitis, trachoma, molluscum contagiosum of the lid, phthiriasis (lice on lashes), scabies and Demodex

Other

• Medication toxicity, environmental irritants, computer vision syndrome
• Systemic itch (cholestasis, uraemia, thyroid disease, iron deficiency, lymphoma), keratoconus related rubbing
• Ocular surface and lid tumours, cicatrising conjunctivitis

Reasoning. Diagnosis is clinical. Test for allergy in recurrent or severe disease, culture for atypical infection, and look for corneal complications and keratoconus.

First line. Slit lamp examination with eversion of the upper lid, fluorescein staining, and lid assessment.

Targeted tests.

• Skin prick tests or serum specific IgE to aeroallergens, with total IgE and eosinophil count as supportive data; tear IgE; conjunctival scraping with Giemsa stain for eosinophils (supports allergic disease).
• Corneal topography for suspected keratoconus.
• Swabs for culture or nucleic acid amplification when infection is suspected. Eyelash examination for Demodex mites.
• Patch testing for contact allergy.
• Intraocular pressure monitoring with steroid use.
• Blood tests for systemic itch (full blood count, ferritin, liver function, urea, creatinine, thyroid function) when generalised itch is present.
• Biopsy for suspicious lid lesions.

Limitations. Allergy tests do not prove clinical relevance. Conjunctival scraping is rarely needed.

General measures (all patients). Stop rubbing, cold compresses, preservative free lubricants to dilute allergens (1 drop 4 to 6 times daily). Avoid known allergens, remove contact lenses during flares or switch to daily disposables, wash face and hair after exposure, keep windows closed in the pollen season, and use wraparound glasses.

Mild to moderate allergic conjunctivitis. Dual action topical agents (antihistamine and mast cell stabiliser): olopatadine 0.1 percent 1 drop twice daily (0.2 percent once daily). Or ketotifen 0.025 percent 1 drop twice daily (age 3 years and older), or azelastine 0.05 percent 1 drop twice daily, or epinastine 0.05 percent 1 drop twice daily.

Mast cell stabiliser alone (sodium cromoglicate 2 percent 1 to 2 drops four times daily, or lodoxamide 0.1 percent 1 to 2 drops four times daily) for prophylaxis, started 2 weeks before the season. Oral antihistamine: loratadine 10 mg once daily or cetirizine 10 mg once daily (5 mg in renal impairment), which may worsen dry eye. Intranasal corticosteroid for associated rhinitis (mometasone 50 micrograms, 2 sprays to each nostril once daily).

Vernal and atopic keratoconjunctivitis (ophthalmology care).

• Topical ciclosporin 0.05 to 0.1 percent 1 drop twice daily to four times daily (steroid sparing, 1 to 3 months to full effect), or tacrolimus 0.03 to 0.1 percent ointment applied to the eye twice daily, or tacrolimus 0.1 percent ointment to eyelids.
• Short pulses of topical corticosteroid for severe flares (fluorometholone 0.1 percent or loteprednol 0.5 percent 1 drop 2 to 4 times daily for 1 to 2 weeks, or prednisolone acetate 1 percent 1 drop 4 times daily for up to 1 week).
• Monitor intraocular pressure and review at 1 to 2 weeks; avoid long term use of steroids because of glaucoma and cataract.
• Supratarsal steroid injection, debridement of plaques and amniotic membrane for shield ulcers.
• Allergy and dermatology care for atopic skin disease; avoidance of eye rubbing to prevent keratoconus; corneal cross linking for progressive keratoconus.

Giant papillary conjunctivitis. Stop lens use, switch to daily disposables or change lens material, clean prostheses, remove exposed sutures, and use mast cell stabilisers.

Contact dermatoconjunctivitis. Remove the allergen (drops, cosmetics), cool compresses, hydrocortisone 1 percent ointment to eyelid skin twice daily for up to 7 days, and patch testing.

Blepharitis. Warm compress for 5 to 10 minutes then lid cleaning twice daily, antibiotic ointment (azithromycin 1 percent drops or chloramphenicol 1 percent ointment to the lid margins at night for 2 to 4 weeks). Doxycycline 100 mg orally daily for 6 to 12 weeks for meibomian gland disease (avoid in pregnancy and children under 12 years). Tea tree oil lid products for Demodex under specialist advice.

Infective causes. Chloramphenicol 0.5 percent drops 4 times daily for 5 days (bacterial); supportive for viral; phthiriasis: mechanical removal and petroleum jelly to lashes twice daily for 10 days, with treatment of contacts.

Floppy eyelid syndrome. Eyelid shield at night and screening for obstructive sleep apnoea.

Rosacea. Lid hygiene, doxycycline, and dermatology care.

Systemic causes. Treat the cause.

Monitoring. Review at 1 to 2 weeks after starting treatment, and at 3 to 6 months for chronic disease. Intraocular pressure with steroids. Keratoconus screening in children with vernal disease.

Referral and escalation. Same day ophthalmology for corneal involvement, pain or reduced vision. Ophthalmology for vernal or atopic keratoconjunctivitis, steroid dependence, and refractory disease. Dermatology and allergy for atopic disease and immunotherapy.

Admission criteria. Rarely needed: severe corneal ulcer or perforation.

Discharge and safety netting. Return for reduced vision, pain, light sensitivity, white spots on the cornea, increasing redness or discharge, or if steroid drops are used for over 1 week.