Diagnosis: Allergic Conjunctivitis
This patient has allergic conjunctivitis, and the recommended treatment is topical antihistamine/mast cell stabilizer drops such as ketotifen 0.035% one drop twice daily. 1
Clinical Reasoning
The presentation strongly points to allergic conjunctivitis based on several key features:
- Itching is the cardinal symptom of allergic conjunctivitis and is the most consistent distinguishing feature from other forms of conjunctivitis 2, 3
- Absence of discharge effectively rules out bacterial conjunctivitis (which presents with mucopurulent discharge and matted eyelids) 4, 2
- Diffuse conjunctival redness without discharge in the context of itching is characteristic of allergic disease 5
- Intermittent nature of symptoms is typical for seasonal or perennial allergic conjunctivitis 5, 3
- Normal fluorescein staining excludes corneal abrasion, keratitis, or other corneal pathology 5
- No vision changes rules out more serious conditions requiring urgent referral 6
Addressing the Floaters
The mild intermittent floaters mentioned are likely age-related vitreous changes and are not related to the conjunctivitis 7. However, this requires clarification:
- Red flags for urgent ophthalmology referral include acute-onset floaters with flashes, visual field defects, or sudden increase in floater density, which could indicate retinal tear or detachment 7
- Since these floaters are described as "mild" and "intermittent" without associated flashes or visual field defects, they are likely benign vitreous opacities 7
- Document carefully whether floaters are new/acute or chronic, as acute-onset floaters require same-day dilated fundus examination with scleral indentation 7
Treatment Protocol
First-line therapy:
- Ketotifen 0.035% ophthalmic solution: 1 drop in affected eye twice daily, every 8-12 hours 1
- This combines antihistamine and mast cell stabilizer properties, addressing both immediate and late-phase allergic responses 3
Patient counseling:
- Remove contact lenses before use and wait 10 minutes before reinserting (though this patient doesn't wear contacts) 1
- Avoid touching dropper tip to any surface 1
- Cold compresses can provide additional symptomatic relief 6
- Identify and avoid allergen triggers when possible 5
Expected timeline:
- Symptoms should improve within 72 hours 1
- If itching worsens or persists beyond 72 hours, patient should return for re-evaluation 1
Important Caveats
When to escalate treatment:
- Development of eye pain (not just pressure/irritation) suggests corneal involvement and requires re-evaluation 6, 8
- Changes in vision mandate urgent ophthalmology referral 6, 1
- Persistent symptoms beyond 4-6 weeks warrant consideration of chronic conditions like atopic keratoconjunctivitis or other diagnoses 4, 9
Avoid common pitfalls:
- Do not prescribe topical antibiotics - they are ineffective for allergic conjunctivitis and promote resistance 5, 6
- Do not use topical corticosteroids as first-line therapy due to risks of cataracts, glaucoma, and infection 3
- Do not dismiss unilateral chronic conjunctivitis - if this becomes chronic and unresponsive to treatment, biopsy is needed to exclude malignancy such as sebaceous carcinoma 4, 9