ลักษณะทางคลินิกแบ่งออกเป็นกลุ่ม ได้ 3 ช่วง คือ (1) prodrome, (2) acute และ (3) chronic.
During initial viral replication, active ganglionitis develops with resultant neuronal necrosis and severe neuralgia.
This inflammatory reaction is responsible for the prodromal symptoms of intense pain that precedes the rash in more than 90% of the cases.
As the virus travels down the nerve, the pain intensifi es and has been described as burning, tingling, itching, boring, prickly, or knifelike.
The pain develops in the area of epithelium innervated by the affected sensory nerve (dermatome).
Typically, one dermatome is affected, but involvement of two or more can occur. The thoracic dermatomes are affected in about two thirds of cases.
This prodromal pain, which may be accompanied by fever, malaise, and headache, normally is present 1 to 4 days before the development of the cutaneous or mucosal lesions.
During this period (before the exanthem) the pain may masquerade as sensitive teeth, otitis media, migraine headache, myocardial infarction, or appendicitis, depending on which dermatome is affected.