Zoster is a unilateral eruption due to reactivation of latent VZV (Varicella zoster virus).
Reactivation of latent VZV.
Zoster is affliction of people who have previouslyhad varicella(chickenpox). Zoster patients are infectious and in susceptible contacts of zoster, chickenpox can occur.
The mean age of zoster patients is about 60 years.
An earlier infection with chickenpox(varicella) is essential before zoster. Chickenpox occurs commonly in childhood and zoster in middle to older age.
The first manifestation of zoster is usually varying degree of pain. Closely grouped red fluid filled lesions develop in a dermatome with a striking cut off at the midline.
Post herpetic neuralgia
The commonest sequel of zoster is postherpetic neuralgia, defined as persistence of pain more than a month after the onset of zoster. PHN increases in incidence and severity with age. It is more likely to develop if there is prolonged and severe pain associated with the eruption. The pain may be a continuous burning sensation with hyperesthesia, or a sudden shooting type, but aitchy ‘crawling’ sensation may also occur.
The pain and symptoms subside gradually as the eruption disappears. In uncomplicated cases recovery may take 2–3 weeks in young, and 3–4 weeks inolder patients.
Shingles is a self limiting infection, but it is painful, and post herpetic neuralgia may occur.
Measures to counteract the infection, provide analgesia and facilitate healing are required.
Rest and analgesia may be sufficient for mild attacks of zoster in the young. Soothing topical preparations relieve discomfort. An antiviral is required for painful zoster infections, in facial zoster and in the immunocompromised. Treatment should start as early as possible, preferably within the first 24-48 hours. Antiviral treatment prevents progression of eruption, reduces the systemic complications of zoster, and lessens the pain during treatment.
Rook’s Textbook of Dermatology Ninth Edition