Infection is usually from another patient. The virus is contained in the body fluids and in the lesions of skin and mucosa. It is transmitted from person to person by droplet infection through the respiratory tract. Rarely the condition may be caused by exposure to a case of Herpes Zoster. Onset is sudden with mild to moderate fever, shivering, pain in the back and malaise.
Rashes break out on the day the fever starts.
The rash appears first on the trunk of the body and then continue to erupt on the face, arms and legs. Mucosal surfaces and the sides of the chest may also be infected. The palms and soles are spared. Laboratory diagnosis is seldom required because of clear-cut clinical signs. Examination of the fluid present within the lesion under the microscope shows characteristic round particles.