Herpes zoster ophthalmicus: The importance of face mask removal examination under the COVID-19 pandemic

Visual case discussion

A 47-year-old lady with Type 1 diabetes mellitus suffered from right forehead and periocular painful skin rash for 2 days. There was no trauma or injury, but her diabetic control was fair only with Hemoglobin A1c of 8.3% but normal renal function tests. Under the COVID-19 pandemic, she worn a face mask upon emergency department attendance, covering up the lower face. Physical examinations showed stable vital signs, and normal body temperature of 37.1 °C. There was obvious right face rash (Fig. 1 ), with some vesicles. Visual acuity was 0.9 Snellen decimal, and intraocular pressures were normal of 12 and 13 mmHg for right and left eye respectively. Oral acyclovir 800 mg of five times per day and topical 5% acyclovir cream for skin rash were prescribed. Contact precaution towards pregnant lady and young children were advised.

Fig. 1.

Patient suffering from right sided (white arrow) herpes zoster ophthalmicus was wearing a face mask upon attendance under the COVID-19 pandemic. Rash was respecting midline. (blue arrow heads) The face mask covered the nose tip masking the positive Hutchison sign.

2 days later, the patient re-attended the emergency department complaining of progressive right eye redness and photophobia. Visual acuity dropped to 0.7 Snellen decimal, and intraocular pressure was elevated of 29 mmHg over the injected right eye. Slit lamp examination found ciliary injection over right eye with epithelial mucoid plaques. Multiple keratic precipitates were found over the inferior part of the corneal endothelium (Fig. 2 ). Fluorescein stain of the cornea revealed dendritic lesions (Fig. 3 ). Anterior chamber cell was 1+, but there was no posterior synechiae nor sectoral iris atrophy. Re-examination of her face with mask removed revealed positive Hutchison sign. Herpetic keratitis and uveitis were diagnosed, and she was treated with topical 3% acyclovir eye ointment five times per day on top of systemic anti-viral treatment. Patient's vision improved back to 0.9 Snellen decimal after 2 weeks of treatment, and vitreous was all along quiet, with retina spared from any necrotic herpetic infection.

Fig. 2.

Slit lamp examination of the right eye revealed keratic precipitate over the inferior corneal endothelium. (white arrow).

Fig. 3.

Fluorescein stain of the right cornea demonstrated dendritic lesions of the corneal epithelium.

Under the COVID-19 pandemic, face mask wearing is widely practiced among the public to prevent aerosols and droplet transmission of the SARS-CoV-2 viruses. Hospital, particularly the emergency department, is treated as high risk area as there are potential COVID-19 patients; and full compliance with face mask upon arrival was suggested by authorities. Being an essential personal protective equipment, face mask covered most of our faces to offer its protective effect. However, subtle but important clinical signs of the face may be missed without taking the face mask off for physical examinations. In our case, examining the nose tip for cutaneous vesicles (Hutchison sign) is significant to predict any intraocular involvement¹.

Herpes zoster ophthalmicus (HZO) is caused by varicella-zoster virus (VZV), one of the 8 known double-stranded DNA human herpesviruses. Following the primary infection of chickenpox, VZV establishes latent infections in neurons of the sensory ganglia, particularly the trigeminal ganglion². When the latent VZV viruses are reactivated, particularly over immunosuppressed patients, shingles (zoster) would present as painful vesicular dermatitis localized over a single dermatome. Ophthalmic division (V1) of the trigeminal nerve is more often affected than the maxillary or the mandibular branches. The natural course of HZO usually starts with maculopapular rash, then vesicles, followed by pustules, and eventually crusting over with individual skin scars. Residual neuropathy pain (post herpetic neuralgia) is common, and could last for months or even years.

Ophthalmic manifestations of HZO include follicular conjunctivitis, uveitis, keratitis (microdendritic, stromal, or disciform), episcleritis, scleritis, cranial nerve palsy or even acute retinal necrosis. Among them, intraocular involvement of VZV is more likely if Hutchison sign is positive; as the nose tip is innervated by the nasociliary nerve, which also innervates the ciliary body, iris, cornea and conjunctiva. Acute infection may sometimes turn into chronic relapsing infection, when chronic inflammation could result in corneal vascularization, corneal scarring, neurotrophic keratopathy, lipid keratopathy, or sectoral iris atrophy.

HZO patients are advised to avoid close contact with children or pregnant ladies, as VZV skin lesions and virus shed in respiratory secretions are highly contagious through airborne transmission. Whenever acyclovir is prescribed, renal function should be checked for necessary dosage adjustment. Acyclovir neurotoxicity is a possible important side effect on renal impairment patients³.

In short, Hutchison sign is an important examination item in HZO cases, as it predicts the likelihood of intraocular involvement. Despite the face mask wearing practice in COVID-19 times, mask removal examination is necessary to look for the Hutchison sign over the nose tip for suspected HZO cases.

Multiple choice questions

Q1. What of the following is a possible ophthalmic manifestation of herpes zoster ophthalmicus (HZO)?

• 1)Dislocated lens
• 2)Keratitis
• 3)Orbital myositis
• 4)Rhegmatogenous retinal detachment
• 5)Trichiasis

Answer: (2) Keratitis

Ophthalmic manifestations of HZO include follicular conjunctivitis, uveitis, keratitis, episcleritis, scleritis, cranial nerve palsy or even acute retinal necrosis. Other choices of ocular signs are not related directly to HZO.

Q2. Which branch of the trigeminal nerve is more often affected by HZO?

1) Ophthalmic branch (V1)

2) Maxillary branch (V2)

3) Mandibular branch (V3) sensory division

• 4) Mandibular branch (V3) motor division

• 5) V2 and V3

Answer: (1) Ophthalmic branch (V1)

Ophthalmic division (V1) of the trigeminal nerve is more often affected than the maxillary or the mandibular branches.

Q3. Which of the following investigations should be checked before prescription of systemic acyclovir tablets?

• 1)SARS-CoV-2 viral test
• 2)Renal function test
• 3)Hemoglobin A1c test
• 4)Fasting blood glucose
• 5)Arterial blood gas

Answer: (2) Renal function test

For renal impairment patients, dosage of acyclovir should be adjusted according to their renal function test results to avoid overdosing with potential acyclovir neurotoxicity. Other test results were not affecting the dosage of acyclovir prescription.