Had Chicken Pox?

You may be a candidate for shingles

John Kraft and Charles Lynde, MD, FRCPC

Everyone with shingles has had chickenpox at some time. Nearly 99% of adults have had chickenpox at some point in their lives, meaning that nearly all adults are at risk for shingles. When the chickenpox skin rash goes away, the virus goes into hibernation (latency) in the nerve roots of the spinal cord. Here it is hidden from the immune system. At some point, triggered by decreased immune function (i.e. older age, stress), the virus comes out of latency. Shingles (Herpes Zoster) is a common skin disease caused by the varicella zoster virus (VZV), a member of the Herpes family of viruses. Read more about this virus on www.HerpesGuide.ca.

How the Virus Works

• The virus replicates in the dorsal root ganglion (root of a sensory nerve of the skin) and migrates down the sensory nerve and affects the skin supplied by that nerve (the "dermatome").
• When it replicates in the skin it causes a maculopapular, red area that develops into fluid filled blisters within 12 to 24 hours.
• The lesion typically spreads to involve the entire dermatome over 3 to 5 days.
• The vesicles become pustules, dry out and crust within the first week.
• Complete resolution normally occurs without scarring in 2-4 weeks. Scarring is more likely if lesions become secondarily infected.

The Pain of It

Pain is present at all stages (before, during and after onset of lesions) and is due to inflammation and destruction of the involved dorsal root ganglia and nerves. The pain normally subsides with the disappearance of the rash. The associated pain may be burning, stabbing, throbbing, or sharp. Other symptoms of shingles may include nausea, vomiting, headache, malaise, fever and enlarged lymph nodes.

Treating Shingles

Shingles should be treated because complications can occur that may be neurological (post-herpetic neuralgia), ocular (i.e. conjunctivitis, uveitis), skin-related (i.e. scarring, bacterial infection), and/or visceral (i.e. especially in immunocompromised patients: pancreatitis, pneumonitis, myocarditis).

The most common, and the main reason why expedient antiviral treatment is essential, is to decrease the likelihood of post-herpetic neuralgia (PHN). PHN refers to the presence of pain in the affected area for more than 1-3 months after the resolution of shingles. It may last from 3 months (50% of PHN patients) to more than a year (27% of PHN patients). It represents VZV-caused nerve damage resulting in hyperalgesia (decreased pain thresholds) and allodynia (pain caused by normally innocuous stimuli).

Treatment Options

Treatment is geared at symptom relief, reducing the skin lesions, and decreasing the risk of scar formation and the occurrence of PHN. Cool baths, calamine lotion, ice, ASA, acetaminophen, and NSAIDS can help with pain and itching.

Since the introduction of acyclovir 20 years ago, antivirals have established themselves as the gold standard in Herpes virus therapy. The newer antivirals, famciclovir (Famvir) and Valacyclovir (Valtrex), have been shown to be even more effective than acyclovir. More about these treatments can be found on www.herpesguide.ca/herpes_treatment/available.html . The key to their effectiveness is to use them in the acute phase; normally within 48-72 hours of the onset of shingles. Unconventional analgesics (i.e. low-dose tricyclic antidepressants, gabapentin) can be used to treat PHN. You may notice improvement in pain over weeks to months.

The key to combating shingles is to get a prompt diagnosis and early comprehensive treatment of shingles with antivirals. This will result in quicker resolution of acute symptoms and reduce your risk of developing long term complications.

About the author:
Charles Lynde, MD, FRCPC is Assistant Clinical Professor, University of Toronto Canada. His special interests include paediatric dermatology, cosmetic procedures, contact dermatitis, skin cancer, psoriasis and clinical trials in acne, eczema, and psoriasis.
John Kraft, HBSc, is a fourth year medical student at the University of Toronto, with an interest in dermatology.

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