1. Consider shingles in any case of undiagnosed pain running along a single dermatome, even without rash. In some cases, the pain may appear up to 2 weeks before the rash. There might also be headache.

2. In a few people, no rash ever appears (Zoster sine herpete). In a very few, more than one dermatome is affected.

3. One in three Canadian adults are expected to get zoster at some point; one in two of those who live to 85. Among Canadians over 65, almost all of whom have had chickenpox, annual zoster risk is over 0.5%. The commonest complication, post-herpetic neuralgia (PHN), appears in about 20% of cases — far more in the elderly.

4. The vaccine Zostavax, approved six months ago, is a high-dose attenuated chickenpox vaccine that prevents half of all cases in adults. It prevents nearly two-thirds in the more vulnerable over-60 age group. It reduces PHN risk by about three-quarters. In subjects who are vaccinated but get shingles anyway, PHN risk is also slightly reduced. Zostavax won’t help patients who already have PHN or a shingles outbreak.

5. The antiviral famciclovir offers a simplified regimen, but aciclovir is much cheaper. Like all antivirals, these drugs are most effective if started very early in the disease course. They can cut risk of PHN.

6. Apart from PHN, the most important complication risk is Ramsay Hunt syndrome, which can mimic Bell’s palsy and may even be mistaken for a stroke at first. Watch for vesicles that appear around the ear. If they do, check the palate for similar vesicles, another warning sign.

7. Vesicles on the point of the nose suggest eye involvement is imminent. Give aciclovir eye drops and refer to an ophthalmologist to prevent permanent corneal scarring and other serious complications.

8. Bacteria can infect the blisters, so there is a potential role for antibiotics. Corticosteroids have been used to control pain, but their use has lately been questioned in several journals. Avoid topical steriods in facial rashes — they will find their way into the eye and reduce its resistance
to infection.

9. Patients with shingles can transmit chickenpox from the point when blisters appear, until they become encrusted. Since Canada vaccinates for varicella at 12 months, the main risk is to infants below this age.

10. Bear in mind that recurrent or very severe shingles may indicate that the immune system is weakening for some other reason.