Varicella Zoster Virus (VZV) – the prudish brother to Herpes Simplex Virus and the bad actor behind Chicken Pox and Shingles.
In this post we try to answer the major questions inspired by last week’s AM Report with Dr. Robbins.
Can you develop Shingles by coming into direct contact with someone with active lesions?
The short answer is NO. Although the virus that causes Shingles (VZV) is primarily transmitted via direct contact with the virus-laden vesicle-juice that oozes from the virus’s characteristic rash (Google “gross shingles” I dare you), the clinical syndrome of “Shingles” is BY DEFINITION the result of viral reactivation.
Can exposure to VZV cause reactivation of the virus?
Nope. Shingles Is Not Contagious. We searched high and low and there is nary a case report to suggest that exposure to the highly contagious vesicular fluid is itself a risk factor for developing Shingles.
What are the most common risk factors for Shingles?
The list of conditions associated with an increased risk of Shingles is ridiculously long … like as long as … well nevermind. Check out an especially good Review Article from the NEJM to read about this and all-things-Shingles. In the end it all boils down to the fact that following primary infection, the human immune system never fully clears this unwanted house-guest of a virus. Sure our VZV-specific T-cells are able to keep this nuisance largely confined to our neurons — one study found evidence of the virus 1% – 7% of the neurons in our body! — but if our immune system loses a step (whether due to age, time lapsed from primary infection, or immunosuppression) so too can our VZV-specific T-cell immunity and then there goes the neighborhood …
How do you define Disseminated Zoster?
Okay guys this is where I start getting tired of typing, especially when the answer is kind of like the answer that Supreme Court judge gave when asked how he knows a painting or picture is pornography rather than just art: “I know it when I see it.” So yeah … I’ll let the CDC take it from here and define disseminated zoster as the following –
“People with herpes zoster most commonly have a rash in one or two adjacent dermatomes (localized zoster). The rash most commonly appears on the trunk along a thoracic dermatome. The rash does not usually cross the body’s midline. However, approximately 20% of people have rash that overlaps adjacent dermatomes. Less commonly, the rash can be more widespread and affect three or more dermatomes. This condition is called disseminated zoster. This generally occurs only in people with compromised or suppressed immune systems. Disseminated zoster can be difficult to distinguish from varicella.”
What should my differential be when I see a rash that looks like Shingles?
PUNT!
Dynamed, take it away:
Other conditions associated with vesicular or papular lesions
-herpes simplex virus (HSV)
-most common alternate cause when clinical diagnosis is incorrect
-dermatomal presentation is rare, but may occur with recurrent HSV
-smallpox
—skin lesions in smallpox are all in same stage of development
-contact dermatitis
-impetigo
-cellulitis
-bites and stings
-cutaneous fungal lesions such as candidiasis
-autoimmune blistering disease
-dermatitis herpetiformis
-drug eruptions
-Sweet syndrome, particularly in immunocompromised patients
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