Definition

Herpes zoster is a disease caused by the Varicella Zoster Virus (VZV). This virus can infect various nerves, including those near the eyes, leading to herpes zoster ophthalmicus. While most individuals globally are immune to VZV, re-infection or reactivation is possible. Herpes zoster ophthalmicus occurs in 10-15% of herpes zoster cases.

Causes

Herpes zoster ophthalmicus is caused by the Varicella Zoster Virus (VZV), which is part of the same viral group as the Herpes Simplex Virus (HSV), the agent responsible for herpes. When VZV infects humans, it manifests as chickenpox, characterized by blisters spread across the body accompanied by fever. Although the initial infection resolves as the immune system responds, the VZV virus does not die but rather remains dormant within the spinal nerves. In a healthy immune system, this virus remains inactive. However, if the immune system weakens, the virus can reactivate, typically infecting the nerves aligned with its dormant location, causing inflammation and potential nerve damage.

In some cases, the reactivated virus affects the nerves serving the skin around the eyes and the cornea. This involves the first branch of the trigeminal nerve, which also innervates facial skin near the upper and lower jaw, leading to herpes zoster ophthalmicus.

Immunosuppression, whether due to diseases like HIV/AIDS or immunosuppressive therapies for conditions such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), can trigger herpes zoster ophthalmicus. Other factors include aging, severe psychological stress, and direct trauma to the nerves harboring the VZV virus.

Risk Factor

The risk factors for herpes zoster ophthalmicus include the virus's ability to infect and the host's immune system status. The incidence increases with age, peaking in individuals over 60.

Conditions that weaken the immune system, such as HIV/AIDS, significantly elevate the risk. Individuals with HIV/AIDS face a 15-fold higher risk of developing shingles and experience more severe recovery and complications.

Therapies that suppress the immune system, such as those for autoimmune diseases, also increase the risk by allowing the VZV virus to proliferate and infect nerves.

Symptoms

Symptoms of herpes zoster ophthalmicus are distinctive and easily recognizable. Initial symptoms include fever, nausea, headache, and eye pain. A few days later, painful blisters appear on the skin around the eyes, eyelids, and near the nose, described as burning or tingling. These blisters typically persist for about 10-15 days before drying up and rupturing.

Pain can also occur in the eyes due to corneal nerve damage, resulting in keratitis, which can impair vision. Inflammation may also involve the iris, leading to elevated intraocular pressure, characterized by severe eye pain.

Diagnosis

Medical Interviews and Eye Examination

Diagnosing herpes zoster ophthalmicus usually does not require laboratory tests. Physicians typically inquire about a history of chickenpox, vaccination, medical treatments, and the presence of blisters elsewhere on the body. A visual acuity test is often conducted to identify any vision disturbances caused by the condition. Additionally, the doctor examines the eyelids, skin around the eyes, and scalp, and measures eye pressure to assess inflammation. Using a slit lamp, the doctor can detect corneal abnormalities and cloudiness in the anterior chamber. Fundoscopy may be performed to inspect the eye’s interior for complications.

A special dye can be used to identify corneal damage. If the dye accumulates in specific areas on the cornea, it indicates damage, often resembling a tree trunk with branches in herpes zoster ophthalmicus.

Laboratory Tests

A corneal swab may be taken for laboratory analysis. The Tzanck test can confirm a viral infection, and specific IgM antibody tests for VZV can be conducted. Additional diagnostic options include viral culture and polymerase chain reaction (PCR) to identify the presence of the virus.

Management

The management of herpes zoster ophthalmicus involves multiple objectives. The primary goal is to reduce the viral infection, typically achieved through antiviral medications prescribed by the doctor. Additionally, to mitigate the potential vision damage caused by ocular inflammation, anti-inflammatory drugs may be administered.

If intraocular pressure increases, medications to lower this pressure will be provided. The pain associated with herpes zoster ophthalmicus can be severe and unbearable, necessitating painkillers appropriate to the pain's intensity.

Monitoring the patient's response to therapy and checking for complications is essential during the first seven days of treatment. Severe cases with significant structural damage to the eyeball may require surgical intervention.

Complications

Complications from herpes zoster ophthalmicus can affect both the skin around the eyes and vision. Scar tissue on the eyelids can impair their function, causing incomplete opening or abnormal folding inward or outward. Inflammation in the sclera (the white part of the eye) can lead to tissue shrinkage, compromising the eyeball's shape. Corneal inflammation may result in scar tissue that disrupts vision. Furthermore, the infection can spread to the optic nerve via the retina, potentially causing blindness. Persistent pain can also occur due to nerve damage, even after the blisters have healed.

Prevention

Vaccination is the primary preventive measure against herpes zoster ophthalmicus. The Varicella vaccine, administered starting at 12 months of age, is given in two doses, spaced 1.5 to 3 months apart. This vaccination can be repeated in older adults if necessary, under a doctor's guidance. It is suitable for anyone, including those with compromised immune systems.

When to See a Doctor?

Immediate medical consultation is advised if you develop clustered blisters around the eyes and nose or on one side of the body. These are typical signs of herpes zoster.

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