Clinical manifestations divided into 3 phases.
Shingles, or herpes zoster (HZ), is an infection caused by the varicella zoster virus (VZV) which remains in the body following an episode of chickenpox. After lying dormant and forgotten for decades in the neurons of a spinal nerve, it reactivates as shingles.
The primary symptom associated with shingles is a painful red rash that erupts along 1 side of the body. Most commonly presenting as a band around the patient’s waistline or trunk, the rash can also break out in other locations like the face, neck, eyes, and ears.
Shingles’ clinical manifestations are divided into 3 distinct phases: preeruptive, acute eruptive, and chronic.
The preeruptive phase (or preherpetic neuralgia stage) usually lasts about 48 hours but can stretch to 10 days in some cases. It is characterized by sensory phenomena along 1 or more dermatomes, which correspond to an area of skin mainly supplied by a single spinal nerve. Symptoms common to this stage include headache, general fatigue, sensitivity to light, and fever.
The acute eruptive phase is marked by a continuation of the physical symptoms of the preeruptive phase, plus severe pain and the emergence of lesions. The lesions start as macules (small circumscribed changes in the color of skin that are flat) and quickly progress to clusters of vesicles filled with fluid. New vesicles continue to form and rupture over a 3-to-5-day period. It is during this phase that the virus is easily transmitted to others. The vesicles eventually dry up and crust over, taking up to 4 weeks to heal. Pigmentation changes and scarring on the skin caused by the lesions may be permanent.
The chronic phase, also known as postherpetic neuralgia (PHN) occurs in up to 20% of all patients with shingles. It is defined as recurrent pain lasting more than 4 weeks after the vesicles have healed. Other symptoms include abnormal skin sensations like tingling, burning, and numbness caused by pressure on a nerve (paresthesia) and nerve damage (dysesthesia). The resulting pain, which can be excruciating and disabling, can last months and even years.
The shingles rash is usually self-limited and resolves without medical intervention, but most patients require relief from the accompanying pain and discomfort. Physical symptoms can be managed with nonsteroidal anti-inflammatory drugs (NSAIDs), wet dressings, and calamine lotion.
The antivirals acyclovir, famciclovir, and valacyclovir are also very effective, especially when prescribed within 72 hours of the onset of symptoms. Hospital admission is reserved for patients with severe symptoms, immunosuppression, disseminated herpes zoster, ophthalmic involvement, and other serious complications.
PHN pain is notoriously difficult to manage. Two options include the topical analgesics found in lidocaine and capsaicin transdermal patches.
In the United States, 99% of individuals aged 50 years and older carry VZV in their bodies after having chickenpox as a child. Approximately 1 million of them will experience shingles each year.
Once VZV is in the body, the only way to protect against shingles and related complications is through vaccination. The Shingrix vaccine is approved by the FDA for use in adults aged 50 and over. Administered in 2 doses delivered 2 to 6 months apart, it is more than 90% effective in all age groups tested.
Additionally, by dramatically reducing an individual’s chances of developing shingles, Shingrix also reduces the likelihood that they will pass along VZV to vulnerable young children and adults who have no immunity to it through vaccination or having had chickenpox.