Maybe you have already had your chicken pox when you were younger but that doesnâ€™t mean that the war is over. Inside your system is a sleeper virus called Herpes zoster that merely hitched a ride on the Varicella virus that causes chicken pox. The Herpes zoster virus reappears when you are in your adult years. This is mainly because you get immunocompromised or immunosuppressed. There are certainly times in your adulthood when you are overwhelmed by stress, malnutrition, and other underlying diseases.