References:
- Global Infectious Diseases and Epidemiology Online Network: Infectious Diseases of the Philippines, 2013 eBook Edition, ISBN 978-1-61755-582-4, by Stephen Berger. Accessed here.
| Agent | VIRUS - DNA. Herpesviridae, Alphaherpesvirinae: Varicella-zoster virus |
| Reservoir | Human |
| Vector | None |
| Vehicle | Air Direct contact |
| Incubation Period | Unknown |
| Diagnostic Tests | Viral culture (vesicles) Serology Nucleic acid amplification |
| Typical Adult Therapy | Acyclovir 800 mg PO X 5 daily X 7 to 10d. OR Famciclovir 500 PO TID. OR Valacyclovir 1 g PO TID |
| Typical Pediatric Therapy | Acyclovir 20 mg/kg PO QID X 7 to 10d |
| Vaccine | Herpes zoster |
| Clinical Hints | Unilateral dermatomal pain, tenderness and paresthesia followed in 3 to 5 days by macular, erythematous rash evolving to vesicles; trunk and chest most common, but other areas possible; patients usually above age 50. |
| Synonyms | Fuocodi Saint’Antonio, Shingles, Zona, Zoster |
The condition represents reactivation of dormant Varicella-Zoster virus in dorsal root ganglia.
Disease is characterized by grouped vesicular lesions distributed along one to three sensory dermatomes, usually unilateral and on the trunk or face.
- Mild pruritis or excruciating pain may be present, and persist after the disappearance of the rash.
- Although pain typically presents for 1 to 3 days prior to the appearance of a rash, the pre-eruptive prodromal period may persist for as long as 18 days.
- In immunocompromised individuals, herpes zoster may become disseminated.
- A chronic verrucous form of herpes zoster seen in HIV-positive patients is associated with antiviral drug-resistance.
Most healthy persons recover without complications; however, individuals above age 50 years are at increased risk of postherpetic neuralgia which may persist for months to years after the rash has healed.
- The possible effect of antiviral drugs in prevention of pos-herpetic neuralgia is controversial.
- Immunocompromised patients are risk for chronic herpes zoster; or infection of the central nervous system, liver, lungs or pancreas.
- Chronic (>1 month) mucocutaneous infections may occur in HIV-positive patients, in the absence of disseminated disease.
- Visual impairment or scleral damage may follow zoster ophthalmia. Over 10% of keratouveitis cases are complicated by secondary glaucoma. Rare instances of orbital apex syndrome and optic neuritis are also reported.
- VZ virus infection may be associated with myotomal paresis, facial nerve palsy or Ramsay-Hunt syndrome (Bell palsy unilateral or bilateral, vesicular eruptions on the ears, ear pain, dizziness, preauricular swelling, tingling, tearing, loss of taste sensation, and nystagmus)
- VZ virus infection can be a presenting symptom of hyperparathyroidism and occurs twice as often in persons with hypercalcemia than age-matched controls.
- In some cases, reactivation of VZ virus may present as radiculitis, cranial nerve palsy or other features of herpes zoster but without rash (zoster sine herpete).