Proper treatment of herpes zoster is ‘a work in progress’
In medical school you may have been taught that herpes zoster infection primarily impacts elderly patients, but the burden of disease is shifting – along with the understanding of herpes zoster itself.
“Herpes zoster is a disease that can lull us into a false sense of security because we see it all the time,” said the annual meeting of the Pacific Dermatologist Association. “But our understanding of how to manage this disease is still very much a work in progress.”
They noted that, while 50 percent of people will acquire herpes zoster by the time they reach 85 years of age because of diminishing cell-mediated immunity, the major burden of disease impacts immunocompromised patients of all ages. HIV patients and solid - organ transplant recipients are well known to face an increased risk of acquiring herpes zoster, but the most overwhelming risk is seen in leukemia patients, who have rates as high as 100-fold that of the general population.
“More recent data on stem cell transplant patients show that about 50 percent of them will get zoster,” added a dermatologist at the University of Southern California, Los Angeles. “Most of that’s happening within the first year and a half after their transplant.”
Several recent epidemilogic studies in the medical literature have reported herpes zoster in patients who are not tradionally believed to be immunosuppressed, such as those with lupus, dermatomyositis, rheumatoid arthritis, asthma, and atopic dermatitis. It begs the question: Is it the disease or is it the treatment?
“We don’t know the answer to that yet. In dermatomyositis and lupus, use of antimalarials has been found to be most associated with the risk of herpes zoster. Other studies looking at one disease are so heterogeneous, some saying that it’s one medication, some saying that it’s another. There’s no cohesive message yet about which medications cause the highest risk of zoster.”
Herpes zoster was originally believed to be far less transmissible than varicella. “Later it was thought that the only way that can get VZV [varicella zoster virus] from a zoster patient was by direct contact with vesicle fluid.
“That turns out to be wrong as well.” One study of pediatric patients found similar rates of secondary varicella cases from varicella and herpes zoster cases (15% vs. 9%, respectively), regardless of the anatomic location of zoster.
Another report that called into question prevailing beliefs about the disease involved an immunocompetent patient in a long -term care facility who developed localized herpes zoster. That individual turned out to be “patient zero” in a varicella outbreak in the facility, even though the person’s lesions had been covered by gauze and clothing at all times. “The next patient who got infected was one of the health care workers who had never been in the room at the same time as the patient but who had changed the patient’s bed linens,” said Dr. Ahronowitz, who was not involved in the study. “Environmental samples were collected from the patient’s room and were contaminated with VZV DNA.”
In addition, VZV DNA has been found in vesicle fluid, serum, peripheral blood mononuclear cells, and saliva. One randomized, controlled trial found that hydrocolloid dressings are superior to traditional gauze and paper dressings in preventing the excretion of aerosolized VZV DNA from skin lesions of patients with localized herpes zoster. Using hydrocolloid dressing to cover lesions “does seem to make a difference.” “Because of all this new data coming out, it’s time to reconsider isolation precautions in all hospitalized patients with herpes zoster, because the consequences of VZV transmission within a hospital where there are other patients nearby who have low immune systems could be absolutely devastating.”
The impact of herpes zoster infection on the central nervous system can be significant, including cranial nerve palsy, encephalitis, encephalopathy, and aseptic meningitis. Patients can have long lasting residual neurologic deficits from this at six months or longer despite appropriate treatment. No correlation between CSF [cerebrospinal fluid] viral load and neurologic sequelae has been found at three months.
More recent research has found an association between herpes zoster infection and an increased risk of stroke – up to threefold in some cases. ‘That risk doesn’t normalize until six months after the infection. Even seeing it in kids, who have two times the risk of stroke in the first 6 months after VZV infection.” MI risk also seems to be elevated as a secondary outcome.
“There have also been recent reports of VZV antigen/DNA found in the vessel wall of patients with giant cell arthritis and granulomatous arteritis of the aorta. This is an evolving story about zoster that we never knew about.”
Drug-induced hypersensitivity syndrome (DIHS) is also associated with CNS manifestations, but they resolve much faster, unlike those of CNS zoster. As long as you take away the offending medication and put them asteroids, they will recover very quickly. At least one case in the medical literature to date has reported DIHS in association with VZV.
The zoster vaccine is currently indicated in patients aged 60 years and older, but since it is a live attenuated vaccine, it is contraindicated in many patients who could benefit most from it, including those with primary immunodeficiency disorders, those with a hematologic malignancy, those who have had a hematopoietic stem cell transplant within the two years, pregnant patients, and patients taking high-dose steroids or anti-tumor necrosis factor biologics.
“There is an inactivated vaccine in the works being tested, and that is showing good efficacy. Hopefully will be able to prevaccinate patients, even young patients, prior to immune suppression.”