Herpes zoster occurs due to the failure of the immune defense system to control the latent replication of the virus, according to research by the National Center for Biotechnology Information.

Herpes zoster, commonly known as shingles, is a viral disease caused by the reactivation of the varicella-zoster virus. Varicella, commonly known as chickenpox, occurs in children. Herpes zoster, on the other hand, occurs in adults and the elderly. According to the article, those who maintain a strong immune system rarely develop shingles. Even after shingles resolves, patients can experience pain known as postherpetic neuralgia.

Shingles has many triggers, including emotional stress, the use of medications such as immunosuppressants, acute or chronic illness, exposure to the herpes zoster virus, and presence of a malignancy. The rate of the virus is 1.2 to 3.4 per 1000 per year among healthy, younger, individuals, according to the article.

However, among patients over the age of 65 years, the rate of the disease is 3.9 to 11.8 cases per 1000 persons per year. Herpes zoster is not seasonal and recurrences are most common in patients who are immunosuppressed.

According to the article, there are 3 stages of herpes zoster infection, the first of which is the preeruptive stage. In this stage, the patient may have abnormal skin sensations or pain within the dermatome. This phase appears at least 2 days prior to any obvious legions. The patient may experience headaches, photophobia, and general malaise.

The second stage is the acute eruptive phase, in which the vesicles and symptoms are in the preeruptive phase. The lesions transform into painful vesicles, which often rupture, ulcerate, and crust over. Often, this phase is unresponsive to traditional pain medication and may last up to 4 weeks, but the pain may continue.

The last phase in chronic infection, in which the pain is recurrent and lasts more than 4 weeks. Patients may also experience paresthesia, shock-like sensations, and dysesthesias. This pain is often debilitating and may last 12 months or longer.

Antiviral therapy can hasten the resolution of lesions and decrease acute pain. It can also help prevent post-herpetic neuralgia, especially in older patients. The main treatments for herpes zoster are Acyclovir 800 mg 5 times per day for 5 weeks, valacyclovir 1 gm 3 times per day for 5 days, and famciclovir 500 mg 3 times a day for 7 days, according to the study. Topical creams can also help to prevent secondary infection. Occasionally, pain may be so severe that opioids are required.

Reference
Nair PA, Patel BC. Herpes Zoster (Shingles) [Updated 2020 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441824/. Accessed October 14, 2020.