Shingles (Herpes Zoster): Causes, Symptoms, and Treatment

Shingles (herpes zoster) develops from reactivation of the varicella-zoster virus (VZV), which remains latent in the dorsal root ganglia and cranial nerve ganglia for life after a chickenpox infection. When cellular immunity wanes, the virus can reactivate and travel along sensory nerve fibers to the skin, causing the typical unilateral, band-like rash confined to a dermatome. Approximately one in three people who have had chickenpox will develop shingles during their lifetime — mostly after age 50.

Reactivation is promoted by declining cellular immunity. Common triggers and risk factors include: advancing age (the greatest risk factor), immunosuppression from medications (corticosteroids, chemotherapy, biologics), HIV/AIDS, organ transplantation, malignancies (especially lymphomas), severe physical or emotional stress, and UV exposure. Risk increases steeply after age 50, roughly doubling each decade.

The disease course has typical phases: Prodromal phase (1–5 days) — pain, burning, tingling, or numbness in the affected dermatome, often without visible rash yet. Eruptive phase — appearance of grouped vesicles on an erythematous base, strictly unilateral and dermatome-bound (commonly on the thorax as a belt, hence the name). The vesicles become cloudy, rupture, and crust over within 7–10 days.

Healing takes 2–4 weeks. Pain is often the dominant symptom and can be intense and difficult to manage.

The most common and feared complication is postherpetic neuralgia (PHN) — persistent neuropathic pain in the affected dermatome that can persist for months to years after the rash has healed. Risk increases with age, affecting up to 30% of those over 60. Herpes zoster ophthalmicus (eye involvement via the ophthalmic nerve) can cause keratitis, uveitis, and vision loss — an ophthalmologic emergency. Other complications include bacterial superinfection, zoster oticus (Ramsay Hunt syndrome with facial paralysis), disseminated zoster in immunocompromised patients, and rarely encephalitis or myelitis.

Antiviral therapy (acyclovir, valacyclovir, or famciclovir) should ideally be started within 72 hours of rash onset — the earlier, the more effective.!! Antivirals shorten disease duration, reduce viral replication, and lower the risk of postherpetic neuralgia. Pain management is essential: analgesics (acetaminophen, NSAIDs), opioids for severe pain, and neuropathic pain medications (gabapentin, pregabalin, amitriptyline) for postherpetic neuralgia. Local wound care and immediate ophthalmologic referral for herpes zoster ophthalmicus are important.

Vaccination is the most effective preventive measure. The recombinant adjuvanted vaccine Shingrix provides over 90% protection against shingles and over 89% protection against postherpetic neuralgia.!! It is recommended for all adults from age 50, as well as for individuals from age 18 with increased risk due to immunosuppression or chronic conditions.

The vaccine requires two doses given 2–6 months apart. Even individuals who have already had shingles can be vaccinated, as recurrences are possible.

When painful blisters appear on one side of your body, time is critical — starting antiviral treatment within 72 hours significantly improves outcomes. Skinscanner can rapidly evaluate whether a new rash is consistent with shingles based on its unilateral distribution, vesicle morphology, and dermatomal pattern. This quick initial assessment can motivate you to seek urgent medical care rather than waiting to see if the rash resolves on its own.

During the healing process, photo documentation helps track the progression from active blisters through crusting to resolution, providing useful information for your healthcare provider. Skinscanner does not replace urgent medical evaluation — shingles requires prompt antiviral treatment and professional management — but it can help you recognize the condition quickly and understand the importance of seeking immediate care.