The virus that causes shingles, varicella zoster, is the same virus which causes chickenpox. It tends to affect two age groups:
|Children, who contract the virus through inhaled virus particles, and get chickenpox|
|The elderly, in whom the virus has lain dormant since the initial chickenpox infection. This manifests itself as shingles, with its very characteristic skin eruptions along the distribution of a single peripheral nerve|
When shingles affects the nerve supplying the forehead and tip of the nose ("Hutchinson's sign"), the eye may become affected.
Of all shingles attacks, 50% affects the trunk and 15% affects the face.
The skin vesicles of shingles is not throught to be very contagious. Children are the reservoirs of the virus, which is transmitted by the respiratory droplets. It may be wise, however, for people with active shingles to avoid vulnerable groups of people, such as the immunosuppressed.
Skin eruptions which can be crusty which follow the territory of a single nerve. In the head, ophthalmologists are most interested in the trigeminal nerve, the first part of which carries sensation from the front of the eye. If this nerve branch is affected, the patient will have crusty weeping skin eruptions on the forehead, eyebrow, and nose. The eruptions do not cross the mid-line of the face (this can be very striking). There may be considerable pain.
The eruptions may be preceded by tingling of the face for 3-5 days.
Post-herpetic neuralgia (persistent pain more than one month after rash) may occur.
|Painful red eye|
|Loss of visual acuity|
|Photophobia (sensitivity to light)|
|Eyelid stickiness or swelling|
Only 10% of people with shingles on the forehead have eye involvement. Of these 50% may develop complications.
It is not known what activates shingles. It is thought that the virus lies dormant in collections of nerve cells (technically called "sensory nerve ganglia") for decades, only to reactivate at a later date (or not at all). Reactivation appears to occur most often in the immunosuppressed and in the elderly (who have declining cellular immunity).
(Do not worry if you do not understand the technical terms)
|Stromal (disciform) keratitis|
|Other kinds of keratitis (dendritic, nummular, exposure, neurotrophic)|
|Retinitis (ischaemic uveitis)|
|Raised intraocular pressure (due to trabeculitis and/or plugging of the trabecular meshwork)|
|Eyelid involvement (cicatrisation, ptosis, lagophthalmos)|
|Ocular nerve palsies (Ramsay Hunt syndrome)|
Tests are usually unnecessary because the clinical picture is so striking.
|Aciclovir 3% eye ointment 5x/day|
|Steroid eye drops (eg. Prednisolone [PredForte, Predsol], Dexamethasone [Maxidex]) may be used if there is severe iritis|
|Cycloplegics to enlarge the pupil (eg. Cyclopentolate, Atropine)|
|Pressure-lowering drops (numerous) if the pressure is raised|
In very severe cases with permanent corneal scarring, a corneal transplant may be considered to restore vision.
|Oral aciclovir may also be given for the shingles if the patient sees the doctor within three days. Beyond this time, it is probably of little use|
|Pain relief is important|
|Skin creams (boracic acid, capsig cream)|
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