Ophthalmic shingles
Shingles is a viral infection that can affect several organs, including the eyes, with varying degrees of severity and possible long-term effects. Its manifestations are primarily cutaneous, affecting the skin of the back, chest, lower abdomen, neck, genitals, and face. Ocular and cerebral involvement in shingles occurs mainly in immunocompromised patients. Unlike ocular herpes, which is common and affects a younger population, ophthalmic shingles is rarer and often more severe, affecting an older population.
A viral infection
Shingles corresponds to a reactivation of the varicella-zoster virus (VZV), which is part of the Herpesviridae group.
In France, it is estimated that over 95% of adults contracted chickenpox in childhood and are therefore carriers of VZV. Transmission occurs through inhalation (respiratory route) of saliva droplets from a child with chickenpox (and not through touching their skin)!
Subsequently, VZV spreads through the respiratory tract, then passes into the blood and lymphatic system, allowing it to reach all organs, including the skin where it will manifest itself through the famous varicella vesicles and papules.
After a single bout of chickenpox, which occurs only once in a lifetime, the VZV virus remains dormant in the body. Then, under certain circumstances, VZV reactivates and spreads along the path of a nerve, causing a rash in the area of the body served by that nerve: hence the name "shingles."
The main risk factors for VZV reactivation (and therefore the onset of shingles) are: a significant decrease in immune defenses, severe trauma, and advanced age. Indeed, it is estimated that after the age of 80, more than 50% of patients who had chickenpox in childhood will develop shingles.
Studies show that 7 to 25% of shingles outbreaks are ophthalmic: the reactivated virus spreads along the ophthalmic nerve, which runs through the scalp, forehead, and the surface of the eye. This results in a painful, vesicular-crusted rash on the forehead and upper eyelid, which is accompanied by eye involvement (inflammation of the surface or inside of the eye) in 50 to 70% of cases.
Therefore, there can be cases of ophthalmic shingles with only skin involvement or only ocular involvement. Ophthalmic shingles affects only one ophthalmic nerve at a time (the left or the right): the rash therefore only affects one half of the scalp, forehead, and the eye on the same side.
Unlike ocular herpes, which can recur several times in the same eye with complete resolution of symptoms between episodes, ophthalmic shingles usually occurs only once on one of the two ophthalmic nerves, but with symptoms that can take a long time to disappear completely (tendency to become chronic). Consequently, the risk of lasting effects is greater, generally requiring treatment for several weeks.
Forms of ophthalmic shingles
The symptoms of ophthalmic shingles are of three types: cutaneous, inflammatory ocular and neurological.
Skin lesions
In its most typical description, ophthalmic shingles begins with a skin lesion, with pain, a burning sensation, followed a few days later by redness and the appearance of blisters and then scabs in the territory of the ophthalmic nerve.
Ocular manifestations generally occur one to three weeks after the rash. Symptoms depend on the nature of the associated ocular involvement, which may be conjunctivitis, superficial or deep keratitis, episcleritis, anterior or posterior uveitis with retinal necrosis.
Zoster conjunctivitis
Conjunctivitis, causing a moderately red, slightly painful eye with itching and discolored discharge, resulting in a stuck-together eye upon waking in the morning. This conjunctivitis affects only one eye.
Zoster episcleritis
Episcleritis, causing localized redness of the eye with moderate pain and discomfort when moving the eyes.
Zoster keratitis
Superficial keratitis is rare in zoster uveitis. It causes localized redness of the eye around the cornea (perikeratic circle), tearing, pain with a foreign body sensation under the eyelid when blinking, and photophobia (difficulty tolerating light, requiring the eyes to be closed). Decreased visual acuity is not always present.
Deep keratitis is more typical of ophthalmic zoster. It is very often associated with anterior uveitis (then called keratouveitis), resulting in a red eye with more intense pain and photophobia than superficial keratitis. Decreased visual acuity is constant and may persist after healing if there is corneal scarring.
Anterior uveitis zoosteritis
Anterior uveitis can be isolated, is the most frequent ocular involvement in ophthalmic zoster (53%), and gives the same symptoms as keratouveitis.
The pain may be more intense due to the accompanying increase in intraocular pressure.
Zosterian posterior uveitis is fortunately rarer, but constitutes the most serious form of zoster disease of the eye, since it can progress to retinal necrosis (permanent loss of vitality of the retina, which leads to a severe decrease in visual acuity).
It mainly affects immunocompromised patients, hence the initial symptoms are often subtle, while the retinal damage is considerable.
Affected patients complain of floaters (perception of shadows or flies in the field of vision), photophobia, and unilateral decreased visual acuity. The eye may or may not be red and painful.
Ophthalmic shingles can cause neurological manifestations, which may include oculomotor paralysis causing diplopia (double vision).
More commonly, chronic pain in the forehead and head that can last for several months, even after the eye and skin have healed: this is called post-herpetic neuralgia.
What to do in case of ophthalmic shingles
The diagnosis of ophthalmic herpes zoster by the patient or their doctor is clear when ocular symptoms occur in a context where skin involvement is typical. As with ocular herpes, the main risk is the worsening of the condition due to delayed treatment or self-medication by the patient.
Self-medication, risk of complications and treatment delays
Bacterial superinfection of keratitis leads to a corneal abscess, which takes longer to treat and can leave corneal scars resulting in permanent vision loss.
Delayed treatment can lead to optic nerve damage in the event of increased intraocular pressure, or can cause damage to the cornea, iris, or lens resulting in impaired visual quality.
Finally, the patient must absolutely avoid self-administering any treatment without consulting an ophthalmologist. In particular, the instillation of corticosteroid eye drops is strictly contraindicated as it can worsen superficial zoster keratitis.
The role of the ophthalmology consultation
An ophthalmological consultation is mandatory, and will specify exactly the nature of the zoster infection in order to prescribe appropriate treatment, which differs depending on the patient's condition: antiviral tablets, cycloplegic eye drops, healing ointment, corticosteroid eye drops or ointment.
Postherpetic neuralgia (pain) often requires the prescription of strong analgesics such as antiepileptics. The ophthalmologist will then recommend regular follow-up appointments, which are essential to ensure proper visual recovery.
In cases of chronic symptoms, the doctor may also suggest long-term treatment to limit the risk of after-effects.
Conclusion
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Ophthalmic herpes zoster is linked to the reactivation of varicella-zoster virus (VZV) contracted in childhood. This recurrence generally occurs once in a lifetime, at an advanced age or in immunocompromised individuals. Ocular manifestations develop subacutely or chronically, with damage that can threaten medium- and long-term vision.
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Early diagnosis is easy because the skin involvement is typical and precedes the eye involvement, but treatment must be prolonged to avoid sequelae that can lead to decreased visual acuity. Regular follow-up by an ophthalmologist is therefore essential to avoid serious consequences of this condition.