Shingles is a disease that arises when the chickenpox virus reactivates. This results in a painful, blistering rash. The cause of reactivation is uncertain but may be related to weakening of the immune system.
A person must have had chickenpox to get shingles. Of those who have had chicken pox, the following people are more susceptible:
A person with shingles can spread the virus to anyone. If the virus spreads to someone who has not had chickenpox, he/she will get chicken pox rather than shingles. The virus is not spread by air, but instead from skin to skin contact.
The virus spreads if the infected person has uncovered, open blisters and someone directly touches these blisters. The blisters are no longer contagious once they form scabs.
Learn more at the American Academy of Dermatology: AAD Shingles.