Herpes zoster, commonly known as “shingles” (帶狀皰疹 or 生蛇), is a disease caused by the reactivation of the varicella-zoster virus (水痘病毒, VZV). After contracting chickenpox in childhood, the virus remains dormant in the dorsal root ganglia. As we age or experience a decline in immunity—due to factors like chronic illness, increased stress, or immunosuppressive medications—the virus may become reactivated, traveling along nerve pathways to trigger a localized inflammatory response. This is the mechanism behind herpes zoster, and the colloquial term “生蛇” (literally “growing snake”) vividly describes the virus “coming alive” along the nerves.

The clinical manifestations of herpes zoster vary. Typically, patients first experience localized nerve pain, often described as a stabbing sensation, which may persist for a few days before the rash appears. Subsequently, red rashes and small blisters emerge along a single-sided dermatome (nerve segment), often arranged in a band-like pattern. These commonly appear on the back or waist but can also affect the head or limbs. As the blisters rupture and crust over, the skin gradually heals, though the process may leave behind pigmentation or minor scars. In some cases, it can lead to prolonged nerve pain known as postherpetic neuralgia (後遺神經痛), one of the most troubling complications of shingles.

The golden window for treating herpes zoster is typically within the first three days of symptom onset. Early use of antiviral medications (抗病毒藥物) can effectively shorten the disease course and reduce the incidence of postherpetic neuralgia and other complications. Antiviral therapy is often combined with pain relievers and topical care to alleviate discomfort and promote skin healing. Generally, the skin lesions of herpes zoster resolve within two to three weeks, but postherpetic neuralgia may persist for weeks, months, or even years, significantly impacting the patient’s quality of life.

Moreover, herpes zoster can lead to severe complications. If the condition affects the eyes, known as herpes zoster ophthalmicus (帶狀皰疹病毒眼症), it may cause vision impairment. If it involves the inner ear, it could result in hearing loss. These complications require prompt medical attention to prevent irreversible damage. Since herpes zoster is a viral disease, its incidence increases with age, making it a particular concern for middle-aged and older adults over 50.

To reduce the risk of developing herpes zoster, the medical community has introduced the herpes zoster vaccine. For individuals aged 50 or older, or those at risk of immune suppression, vaccination can significantly lower the chances of viral reactivation, thereby reducing the occurrence of herpes zoster and its complications. Vaccination has been incorporated into public health initiatives in many countries worldwide, playing a vital role in improving the quality of life for older adults.

In summary, herpes zoster is a viral skin condition caused by the reactivation of the varicella-zoster virus , which lies dormant in the body for years and becomes active again when immunity weakens. It typically begins with nerve pain, followed by band-like red rashes and blisters along a dermatome, potentially leaving scars or persistent nerve pain. Early antiviral treatment and appropriate pain management are critical to preventing complications, while vaccination is recommended for middle-aged and older adults to lower the risk of onset. Understanding the mechanisms and treatment options for this common and potentially debilitating condition empowers us to respond promptly, safeguarding our own health and that of our families.