Herpes zoster ophthalmicus, or shingles in the eye, results from the reactivation of the varicella-zoster virus (VZV), the same virus that causes chickenpox. After an initial chickenpox infection, VZV can remain dormant in nerve cells for decades. When it reactivates in the ophthalmic division of the trigeminal nerve, it can lead to shingles affecting the face and potentially the eye. This condition can cause severe ocular complications, making accurate identification necessary.
Recognizing the Early Signs
Shingles in the eye often begins with a prodromal phase, characterized by tingling, burning, or pain on one side of the scalp, forehead, or cheek. This sensation may precede a rash by one to three days. Fever or headache can also accompany this initial stage. The rash typically evolves from maculopapular lesions to fluid-filled blisters, which then become pustules and eventually crust over. These skin lesions are usually confined to one side of the face, forehead, or around the eye.
A significant indicator of potential eye involvement is lesions on the tip, side, or root of the nose, known as Hutchinson’s sign. This suggests the nasociliary nerve, which supplies sensation to the eye, may be affected. Beyond the skin rash, specific ocular symptoms may develop, including eyelid swelling, redness, pain, and irritation. Individuals might also experience excessive tearing, increased sensitivity to light (photophobia), or blurred vision.
Clinical Assessment by a Doctor
When a person seeks medical attention for suspected ocular shingles, diagnosis begins with a comprehensive medical history. The doctor will inquire about a history of chickenpox, previous shingles episodes, and vaccination status. A detailed account of current symptoms, including their onset, progression, and location, is also obtained. This information helps clinicians understand potential viral reactivation.
Following the history, a physical examination focuses on the characteristic rash. The doctor assesses its distribution to confirm it follows a dermatomal pattern, confined to the area supplied by a single nerve. The appearance of the lesions (macules, papules, vesicles, or crusted areas) provides further clues. Particular attention is paid to Hutchinson’s sign, which raises suspicion of eye involvement.
A thorough eye examination is a central part of the diagnostic evaluation. This includes testing visual acuity and an external assessment of the eyelids and surrounding skin. Slit-lamp biomicroscopy allows for a magnified view of the eye’s anterior structures, enabling the detection of inflammation, corneal involvement (e.g., punctate keratitis or pseudodendrites), and signs of uveitis (inflammation inside the eye) like cell and flare. Measuring intraocular pressure helps identify potential glaucoma, and a dilated funduscopic exam allows for inspection of the retina and optic nerve. Corneal sensation may also be tested.
Specific Diagnostic Procedures
While clinical presentation and examination findings are often sufficient for diagnosing shingles in the eye, specific laboratory tests can confirm the presence of the varicella-zoster virus. This is especially true in cases with atypical symptoms or when differentiation from other conditions is necessary. Samples are typically collected from fluid within skin blisters, corneal scrapings, or eye fluid.
Polymerase Chain Reaction (PCR) testing is a highly sensitive method for detecting VZV DNA in these samples. PCR provides rapid confirmation. Direct Fluorescent Antibody (DFA) testing is another effective method that identifies VZV antigens within infected cells. Both PCR and DFA are more sensitive and specific than older methods.
Viral culture, though less sensitive and slower than PCR or DFA, can also be used to grow the virus from a sample, confirming its presence. However, results can take several days to weeks. These laboratory procedures help confirm the diagnosis and guide appropriate management.
Importance of Timely Identification
Prompt and accurate diagnosis of shingles in the eye is important due to the potential for severe and lasting ocular complications. If left undiagnosed or untreated, the condition can lead to chronic eye pain, known as post-herpetic neuralgia. Other serious outcomes include corneal scarring, corneal ulcers, and significant inflammation within the eye, such as keratitis or uveitis.
The inflammation associated with ocular shingles can also result in elevated intraocular pressure, potentially leading to glaucoma. In severe instances, these complications can cause permanent vision loss or blindness. Early diagnosis allows for the timely initiation of antiviral medications, which can significantly reduce the infection’s severity and duration. This intervention also lowers the risk of developing sight-threatening complications.