In a 16‑year‑old male with a first episode of herpes zoster on the left T4 dermatome, which of the following statements is true? a) It can occur in individuals who received the varicella vaccine; b) It occurs almost exclusively in young immunocompromised patients; c) Post‑herpetic neuralgia occurs only in immunocompromised hosts; d) Lesions last about six weeks after a one‑week prodrome.

Herpes Zoster in a 16-Year-Old: Key Clinical Facts

The correct answer is (a): Herpes zoster can occur in individuals who received the varicella vaccine. 1, 2

Understanding Vaccine-Associated Herpes Zoster

Vaccine recipients can develop herpes zoster because the live attenuated vaccine virus establishes latent infection in dorsal root ganglia, just like wild-type varicella virus. 2 After vaccination, the attenuated virus replicates in the skin, travels via sensory nerves to become latent in ganglia, and can later reactivate to cause herpes zoster—sometimes within months to years after immunization. 2

• Herpes zoster from vaccine virus often reactivates in the same dermatome where the original vaccine was administered (typically the deltoid region, corresponding to C5-T1 dermatomes). 2
• In immunocompetent vaccinated children, herpes zoster can occasionally be as severe as disease following wild-type varicella infection. 2
• The risk of transmission of vaccine-associated VZV is extremely low—only 3 transmission events reported among approximately 15 million vaccine doses, all resulting in mild disease. 1

Why the Other Answers Are Incorrect

Option (b): "Occurs almost exclusively in young immunocompromised patients"

This statement is false. Herpes zoster predominantly affects older adults and immunocompromised individuals of any age, but it also occurs in younger immunocompetent persons. 3, 4, 5

• HZ affects 20-30% of all individuals during their lifetime, with incidence increasing to 50% in those ≥80 years old. 3
• While immunocompromised patients have 20-100 times higher risk, the disease is not exclusive to this population. 5
• More than half of all herpes zoster cases occur in persons older than 60 years. 6
• HZ does occur in younger, immunocompetent individuals, though it is usually milder with rare complications. 3

Option (c): "Postherpetic neuralgia occurs only in immunocompromised hosts"

This statement is false. Postherpetic neuralgia (PHN) is the most common complication of herpes zoster and occurs primarily in elderly patients, not exclusively in immunocompromised hosts. 3, 4, 5

• PHN affects approximately one in five patients with herpes zoster overall. 5
• Both HZ and PHN are most common in the elderly due to declining cell-mediated immunity from immune senescence. 3
• PHN is defined as pain in a dermatomal distribution sustained for at least 90 days after acute herpes zoster. 5
• While PHN is exceedingly rare in children (even those with vaccine-associated herpes zoster), it can occur in immunocompetent adults, particularly older individuals. 2, 3

Option (d): "Lesions last about 6 weeks preceded by pain along a dermatome by 1 week"

This timeline is inaccurate. The actual clinical course is much shorter. 7, 8, 5

• Prodromal pain typically precedes the rash by only 1-3 days (24-72 hours), not one week. 7, 8
• Lesions continue to erupt for 4-6 days in immunocompetent hosts. 7, 8
• The total disease duration is approximately 2 weeks (not 6 weeks) in otherwise healthy individuals. 7, 8
• The rash typically progresses from erythematous macules to papules to vesicles that crust over within 7-10 days. 5
• The entire course from prodromal symptoms to complete healing takes 2-4 weeks. 7

Clinical Implications for This 16-Year-Old Patient

Given the patient's age and presentation, consider the following diagnostic and management approach:

• Verify vaccination history: If the patient received varicella vaccine, the herpes zoster may represent reactivation of vaccine virus. 1, 2
• Screen for underlying immunodeficiency: While herpes zoster can occur in immunocompetent adolescents, evaluate for HIV infection, diabetes, malignancy, or immunosuppressive conditions. 8
• Laboratory confirmation may be warranted in this atypical age group: PCR of vesicle fluid is the most sensitive and specific test (approaching 100% sensitivity/specificity). 8
• Initiate antiviral therapy: Oral acyclovir, valacyclovir, or famciclovir should be started ideally within 72 hours of rash onset. 5
• Monitor for complications: Although postherpetic neuralgia is exceedingly rare in children and adolescents, patients with vaccine-associated herpes zoster have a low but real risk of meningoencephalitis and should be observed carefully for several weeks. 2