A 45-year-old HIV-positive man presents with painful rash to the left side of the face after “going on a hike.” It had started four days earlier with burning on the skin, which progressed to small blisters. He denies fever, headache, ear pain, and vision or hearing changes. He has applied ice to the area without relief.
What is the diagnosis?
Eight herpes viruses infect humans. The varicella zoster herpes virus (VZV) serotype causes two distinct clinical syndromes. Chickenpox, the primary infection, is extremely contagious and common. After an initial infection, the VZV lays dormant in nerve cells (dorsal root ganglion) until reactivated, causing shingles (herpes zoster). (New Engl J Med 2002;347:340.) The exact pathophysiology and etiology of VZV reactivation is unknown (Lancet Infect Dis 2004;4:26), but an age-related decline in VZV-specific cell-mediated immune responses appears to be important. (JAMA 2009;302:73.)
Shingles affects as many as one in every 278 adults each year in the United States, with more than 92 percent having no identifiable immunocompromising condition. (Mayo Clin Proc 2007;82:1341.) Approximately 35 percent of all people will develop shingles in their lifetime, but recurrent events in immunocompetent persons are uncommon. (JAMA 2009;302:73.) Approximately one million cases of shingles are diagnosed in the United States each year. (JAMA 2011;305:212.) Risk factors besides being over 50 and immunosuppressed are unknown.
A prodrome of generalized malaise, fever, headache, fatigue, chills, and a burning or tingling pain may precede the rash up to five days. Classically the shingles rash is in a unilateral dermatomal distribution, not crossing the midline (see photo 2). It begins as a maculopapular rash followed by a cluster of clear vesicular blisters on an erythematous base. The lesions then evolve over three to five days, and can coalesce into larger lesions that progress into puastules and eventually open and crust over. Rash sensations can range from pruritic to painful. Acute pain occurs in most (95%) patients, with nearly half reporting severe pain. Pain persisting for more than one month is reported in nearly 70 percent of patients over 50. (JAMA 2009;302:73.)
The ophthalmic distribution of the trigeminal nerve (herpes zoster opthalmicus, ophthalmic zoster) is the most commonly affected cranial dermatome (15% of all shingles cases). (Opthalmology 1991;98:1216.) Early diagnosis, treatment, and referral to an ophthalmologist is prudent to prevent corneal involvement and impaired or loss of vision. Other facial nerves also can be involved causing ocular palsies, but this is less common.
Less than one percent of patients may develop Ramsay Hunt syndrome, a VZV infection of the facial nerve sensory branch in the geniculate ganglion associated with ipsilateral facial paralysis, loss of taste sensation in the anterior two-thirds of the tongue, vertigo, ear pain, and internal and external auditory canal vesicles. Patients also may have Hutchinson's sign (named after Sir Jonathan Hutchinson), a herpetic vesicle on the tip of the nose (via the nasociliary branch of the trigeminal nerve which also innervates the cornea) that precedes the development of ophthalmic herpes zoster. (Ophthalmic Hospital Reports and Journal of the Royal London Ophthalmic Hospital, 1865;5:191; 1864;3:865.)
Because the rash has characteristic features, shingles is typically a clinical diagnosis. If laboratory confirmation is required, direct fluorescent antigen assay (lesion scraping smeared on a slide and stained) or DNA polymerase chain reaction techniques are superior to culture. (JAMA 2009;302:73.)
Antiviral medications (acyclovir, valacyclovir, and famciclovir) can shorten the duration of symptoms, decrease the severity of infection, and decrease the duration of pain (acyclovir only [Cochrane Database Syst Rev 2009 Apr 15;) if taken within 72 hours of symptom onset. Otherwise, supportive care is the mainstay of treatment. Some advocate the use of corticosteroids in the immunocompetent older patient to decrease the risk of developing postherpetic neuralgia, but this is considered controversial. (JAMA 2009;302:73.)
Adequate pain control is the desired primary endpoint for most patients. This can be challenging in the immunosupressed or elderly patient. Long-acting opiods are preferred to short-acting formulations. Gabapentin (Neurontin), tricyclic antidepressants, and pregabalin (Lyrica) are also popular treatments, but each has a notable side effect profile that needs to be considered.
Patients should be told to keep weeping lesions covered because those not previously exposed to VZV (never had chickenpox or never vaccinated against VZV) are susceptible. This also prevents scratching lesions that can become secondarily infected or scar. Good hand hygiene is also recommended. Once lesions are completely crusted over, the contagious phase is complete. (JAMA 2011;305:212.) Total healing takes approximately two to four weeks, and residual scarring can occur.
The most common complication of shingles is postherpetic neuralgia, defined as pain persisting at 120 days after disease onset. This debilitating complication is more common with age (as high as 40% in those over 60). Secondary skin infection is a rare but noted complication of shingles, occurring in approximately two to three percent of cases. Encephalitis, pneumonia, myelitis, granulomatous arthritis, acute retinal necrosis, herpes gangrenosum (herpetic necrotizing fasciitis), cranial and and peripheral nerve palsies are rare complications of shingles infections. (JAMA 2009;302:73.)
In March 1995, the FDA approved the Oka varicella vaccine for administration in children 19 to 35 months. (JAMA 2009;302:73.) This helped to decrease the incidence of primary varicella infection, but was not adequate to prevent shingles in those previous inoculated. As a result, the Zostavax (Merck & Co.) vaccine was approved in 2006 for those 60 and older to prevent zoster infection. This is a live attenuated vaccine, and not recommended for patients who are pregnant, under a year old, or immunocompromised. (MMWR Recomm Rep 2008;57[RR-5]:1.) Because only those who have previously been infected with VZV can get shingles, this vaccine does not prevent infection but does prevent reactivation of the latent virus by suppression. It has been shown to reduce the incidence of infection by more than 50 percent. (JAMA 2011;305:212.) It also reduces the incidence of long-term VZV-related neuropathic pain (67%), VZV-associated hospitalizations (J Infect Dis 2008;197:825), and ophthalmic herpes zoster. (JAMA 2011;305:160.)
This patient was discharged with close follow-up in the infectious disease clinic given his underlying HIV status.
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