Exclude viral retinitis following pupil dilatation (especially in immunocompromised patients e.g. HIV, transplant) as this would warrant emergency (same day) referral
- HSK is a corneal infection with herpes simplex virus often with a central corneal ulcer
- Commonest form is epithelial keratitis, accounting for 50% to 80% of ocular herpes
- Less commonly Blepharoconjunctivitis, keratitis, iridocyclitis or acute retinal necrosis.
- Usually a Type 1 HSV infection due to reactivation
- Due to stress, sun exposure, fever, menstruation, medications
- Symptoms and signs include foreign body sensation
- Lacrimation, photophobia, and conjunctival hyperaemia.
- Typically unilateral, rarely bilateral, especially in severely atopic patients
- Epithelial: Initially punctate lesions, coalescing into a dendriform pattern. dendritic ulcer, single or multiple. Associated with reduced corneal sensitivity. Enlargement can result in an 'amoebic' or 'geographic' ulcer (especially following inappropriate use of topical steroids)
- Stromal: Necrotic stroma, stromal infiltrates, vascularisation, scarring, keratic precipitates, and in the anterior chamber, uveitis, possibly raised intraocular pressure
- Disciform keratitis: Central or eccentric zone of epithelial oedema overlying an area of stromal thickening. Folds in Descemet's membrane, uveitis and keratic precipitates
- Metaherpetic ulcer (trophic keratitis) : Due to a combination of denervation, drug toxicity, persistent defects in epithelial basement membrane
- Isolation and characterisation of virus from corneal swab or biopsy
- Herpes zoster keratitis
- Bacterial, fungal or amoebic keratitis
- Acute Herpes Simplex: in non-contact lens wearing adults and where HSK is confined to the epithelium, commence antiviral therapy with one of the following:
oc. aciclovir 3%, e.g. Zovirax, ophthalmic preparation, 5x daily
ganciclovir 0.15% ophthalmic gel (Virgan), 5x daily. Have a low threshold for referral for this condition
- Recurrent Herpes Simplex: where there is: a clear history of previous attacks
no doubt about the diagnosis and only epithelial involvement
commence antiviral therapy (as above). With recurrence, the disease may extend into the corneal stroma and cause a red-eye, ocular discomfort, blurred vision, and corneal scarring. The treatment of stromal involvement is multifactorial and may not be successful. Corneal transplantation may be needed.
- Acute or recurrent epithelial HSK with no stromal involvement: alleviation or palliation; but refer urgently (within one week) to an ophthalmologist if epithelium has not healed after seven days
- If stroma involved, or in children or contact lens wearers, or in bilateral cases): emergency (same day) referral to an ophthalmologist
- Severe cases: Antivirals (e.g. (e.g., ganciclovir 0.15% ophthalmic gel five times daily for at least 1 week or until healed) and/or systemic) + /-Topical steroid
- Surgical debridement. Penetrating keratoplasty in some quiescent cases with scarring
- Avoid touching eyes if you have a cold sore/blister
- Do not use steroid eye drops unless you are taking an anti-viral medicine
- Stop wearing contact lenses if you keep getting infections.
- Complications include uveitis, keratitis, and glaucoma