Observations on herpes zoster: 1. Residual scarring and post-herpetic neuralgia; 2. Handedness and the risk of infection.

The risk of developing post-herpetic neuralgia is related to the degree of residual scarring. Subjects over the age of 60 with more than 10 cm2 of residual scarring have a very high risk of developing intractable post-herpetic neuralgia. Left-handed subjects are less likely to develop herpes zoster, and this could be due to a more efficient immune system.