Herpes Zoster, commonly known as Shingles, is the painful reactivation of the chickenpox virus (Varicella Zoster Virus). Anyone who has had chickenpox or received the Varicella vaccine is at risk for developing Herpes Zoster. After recovering from chickenpox or after receiving the vaccine, the virus can lie dormant in your nervous system for years. If the immune system is weakened (more commonly occurring in the elderly) the virus can reactivate, travel down a nerve pathway and cause the painful rash of Herpes Zoster. A vaccine has been developed for Herpes Zoster, Zostavax, but it is not 100% effective.
Samantha Erie, MSPAS, PA-C and Karen Graham PhD, MPAS, PA-C summarize the key points of the Herpes Zoster in their article A Review of Herpes Zoster in the Journal of Dermatology for Physician Assistants, Volume 9, Number1, Winter 2015. Below are excerpts from the article.
“Approximately 70-80% of patients will experience a prodromal sensation in the affected dermatome. This sensation can be felt as a pain or pruritis and precedes the rash typically by 2 to 3 days, but can be up to 1 week. Patients with prodromal pain alone, presenting without the rash, can create a confusing clinical picture. This pain can resemble pleuritic pain, myocardial infarction, abdominal disease, migraine headache, etc. and can lead to an extensive work-up without diagnosis until the characteristic rash reveals itself. As such, Herpres Zoster should be included in the differential diagnosis of any older patient with dermatomal pain. Constitutional symptoms such as headache, photophobia, malaise and lymphadenopathy can also occur before a rash.
The characteristic rash begins with a brief erythematous papular phase that evolves rapidly into painful vesicles within 1 to 2 days. Vesicles continue to appear over the next 3 to 4 days. Lesions of all sizes and stages may be present at the same time, contrasting the presentation of the uniform vesicles of herpes simplex virus. Vesicles are typically clustered be can be individual/separate and either umbilicated or ulcerated before forming crusts. Crusts usually resolve within 3 to 4 weeks, but may leave scarring and/or hypo or hyperpigmentation for a longer period. The continued appearance of new vesicles for greater than a week should increase suspicion of immune deficiency.
The rash of Herpes Zoster is generally limited to the skin of a single dermatome, with the thoracic dermatomes most commonly affected. Due to the variation in the innervation patterns among patients, the eruption may involve one or two adjacent dermatomes.
Antiviral therapy should be initiated as soon as possible, ideally within 48 hours of rash onset, to accelerate healing and reduce the duration and severity of pain. The oral antiviral medications acyclovir, valacyclovir, and famciclovir are nucleoside analogs and are FDA-approve for treatment of acute Herpes Zoster. Treatment is most effective when started within the first 48 hours of infection, but it is reasonable to use antiviral therapy in the patient seeking medical treatment more than 48 hours after the vesicles appear if the lesions are not completely crusted.
Careful education about Herpes Zoster should accompany the treatment plan. The patient should be made aware that the vesicular rash of Herpes Zoster is a risk to individuals who have not had primary varicella or received the varicella vaccine. One study found that 15.5% of susceptible household contacts developed varicella after exposure to Herpes Zoster. Patients should be advised to keep the rash clean and dry, to avoid the use of topical antibiotics, and to keep the areas covered until all of the lesions have crusted. Care must be taken to avoid contact with those at high risk including pregnant women, infants, and immunocompromised individuals.
Postherpetic Neuralgia-(PHN) is the most common complication of Herpes Zoster and involve pain that does not resolve after the rash heals, but persists for months to years. The definition of PHN differs between clinical studies, persistent pain varying from 30-120 days from disappearance of the rash. Regardless of the arbitrary definition of PHN, the pain experienced by these patients can be severe, creating significant effects on quality of life including emotional distress. The pathophysiology of PHN remains unclear. Risk factors for PHN include older age, greater acute pain intensity during the active phase, greater severity of the rash, and greater severity of a painful prodrome.
Herpes Zoster Ophthalmicus – is the involvement of the ophthalmic nerve or first division of the trigeminal nerve. The Herpres Zoster ophthalmicus rash extends from eye level to the vertex of the skull but does not cross the midline. Vesicles on the nose (Hutchinson sign) indicates a high likelihood of serious ocular complications. An immediate referral to ophthalmology should be made. Fifty percent of patients with Herpes Zoster ophthalmicus who are not treated with antiviral therapy will develop ocular complications (e.g., keratopathy, episcleritis, iritis, etc.).”
It is important to recognize the characteristic rash of Herpes Zoster and to seek immediate treatment in order to lower the risk of serious complications.