Herpes zoster commonly known as shingles and also known as zona, is a viral disease characterized by a painful skin rash with blisters in a limited area on one side of the body, often in a stripe.
Anyone who has recovered from chickenpox may develop shingles, including children. However, shingles most commonly occurs in people 50 years old or older. The risk of getting shingles increases as a person gets older. People who have medical conditions that keep the immune system from working properly, like cancer, leukemia, lymphoma, and human immunodeficiency virus (HIV) infections, or people who receive drugs that weaken the immune system, such as steroids and drugs given after organ transplantation, are also at greater risk to get shingles.
Shingles usually starts as a rash on one side of the face or body. The rash starts as blisters that scab after three to five days. The rash usually clears within two to four weeks.
Before the rash develops, there is often pain, itching, or tingling in the area where the rash will develop. Other symptoms of shingles can include fever, headache, chills, and upset stomach.
Diagnosis of Herpes zoster
The diagnosis of herpes zoster is usually clinical, with laboratory tests reserved for more atypical cases. The ideal specimen is a swab from the base of burst new vesicles in viral transport
medium. This can be processed for direct fluorescent antibody testing (1–2 hour turnaround time), DNA testing by PCR (turnaround time of one day, but more sensitive especially in older lesions) and
viral culture (takes 1–2 weeks and is less sensitive than PCR). Serology for antibodies to varicella zoster virus usually adds little to the diagnosis and may be falsely negative in early
presentation due to waning IgG antibodies below detectable levels.
Pain Management of Herpes zoster
Treating the pain associated with herpes zoster, particularly in the acute stage, is considered an integral component of management and may have benefits in reducing the severity and incidence of
postherpetic neuralgia. This should follow a stepwise approach based on current Australian guidelines.11 These have been summarised in Table 1. Of note, one double-blind randomised controlled trial showed a reduction in incidence of postherpetic neuralgia at six months by about half with early (within 48 hours of rash
onset) commencement of low-dose amitriptyline 25 mg at night (for 90 days) although caution must be used when treating the elderly.12
Pharmacological management of postherpetic neuralgia follows a similar stepwise approach and may additionally involve the use of gabapentin or pregabalin and topical capsaicin. Transcutaneous
electrical nerve stimulation (TENS) may also be useful.