What causes shingles to flare up? Is it contagious? What treatments are recommended?
Clearly, people with impaired immunity (from underlying disease or aging) are at greater risk, but shingles does happen to healthy young adults and it isn't clear why. It is nothing more than reactivated chicken pox, because that virus never leaves the body, it just becomes latent (quiet). It is contagious to people who have never had chicken pox.
Shingles responds to antiherpesvirus drugs used at a higher dose than is required for herpes simplex, be healing faster than it would without therapy.