Shingles is a viral infection that is caused by the same virus which causes chickenpox. The virus is commonly reactivated later in life. It may occur because of trauma or immunosuppression. Following chickenpox infection as a child, the virus lives in the nerves until it is reactivated. It may then return in a localized fashion often found in the course of a nerve on one side only, typically on the torso. Occasionally shingles can be widespread, particularly in patients who are immunosuppressed. It may present as watery blisters on red, irritated skin and can be quite painful. Aggressive treatment early on may help prevent the evolution of pain after the rash has disappeared. There is no cure for shingles, but prompt treatment with prescription antiviral drugs, drying starch lotions and systemic cortisone can speed healing and reduce the risk of complications.