Herpes zoster is a neurocutaneous disease that is caused by the reactivation of varicella-zoster virus (VZV) from a latent infection of dorsal sensory or cranial nerve ganglia following primary infection with VZV earlier in life. (Schmader et al 2007).
In addition to general factors, such as advanced age and female gender, inflammatory rheumatic diseases and their immunosuppressive treatment are important risk factors for the occurrence of herpes zoster.
1. Prodrome stage (pre-herpetic neuralgia): which usually lasts for few days and is characterized by nonspecific local and general symptoms.
2. Acute stage (AHZ): which is marked by the eruption of skin rash in the affected dermatome and the development of VZV-induced neuritis.
3. Post-herpetic neuralgia (PHN): which is defined as pain persisting more than 3 months after the onset of the rash in the same affected area. (Hadley et al, 2016).
Patients with PHN may experience multiple types of pain including:
The diagnosis of HZ is mainly a clinical one and can be made with high confidence due to the characteristic clinical symptoms of this condition (unilateral, dermatomal, vesicular rash and neuralgic pain in an older patient). The initial clinical symptoms of herpes zoster are often non-specific and may lead to initial misdiagnosis.
Typically, a single dermatome is involved, although two or three adjacent dermatomes may be affected. The lesions usually do not cross the midline. Herpes zoster can also present with unique or atypical clinical manifestations, such as glioma, zoster sine herpete and bilateral herpes zoster, which can be a challenging diagnosis even for experienced physicians.
Laboratory tests: polymerase chain reaction (PCR) is used to confirm the diagnosis, especially in cases of atypical HZ presentation.
Acute stage:
Post-herpetic neuralgia:
Pharmacological treatments: Topical lidocaine patch 5%, gabapentin, pregabalin, opioids, tricyclic antidepressants (TCAs), tramadol and topical capsaicin cream and patch. Sometimes a combination of these drugs can be used for more effective results.
Non-pharmacological treatments:
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