[Reactivation of herpes zoster infection by varicella-zoster virus].

HISTORY: There has been considerable interest in varicella-zoster virus in the middle of the twentieth century. Virus isolation in 1958 had made it possible to find out the complete DNA sequence of the varicella-zoster virus. Molecular identify of the causative agents of varicella and shingles had been proved. ETIOPATHOGENESIS AND HISTOPATHOLOGY: Varicella-zoster virus is a member of the Herpesviridae family. After primary infection which results in varicella, the virus becomes latent in the cerebral or posterior root ganglia. Some of these individuals develop shingles after several decades because of virus reactivation. It is caused by decline of cellular immune response. Circumstances such as old age, hard work, using of steroids or malignancies contribute to the appearance of shingles. Histopathological findings include degenerative changes of epithelial cells such as ballooning, multinucleated giant cells and eosinophilic intranuclear inclusions.

EPIDEMIOLOGY: Shingles occur sporadically, mainly among the elderly who have had varicella. There is no seasonal appearance of shingles. Individuals suffering from shingles may be sometimes contagious for susceptible children because of enormous amount of virus particles in vesicle fluid.

CLINICAL FEATURES: Clinically, shingles is characterized at first by pain or discomfort in involved dermatome, usually without constitutional symptoms. Local edema and erythema appear before developing of rash. Maculopapular and vesicular rash evolves into crusts. The most commonly involved ganglia are: lumbar, thoracic, sacral posterior root ganglia, then geniculate ganglion of the VIIth cranial nerve and the trigeminal ganglion. The most common complication, postherpetic neuralgia, may last for as long as two or three weeks, sometimes even one year or more. Other complications that may be seen in shingles, but more rarely, are ocular (keratitis, iridocyclitis, secondary glaucoma, loss of sight), neurological (various motor neuropathies, encephalitis, Guillain-Barre syndrome), secondary bacterial infection of vesicles. Immunocompromised patients often develop more severe disease lasting up to two weeks, skin lesions are more numerous and often with hemorrhagic base and there is a high possibility for cutaneous dissemination and visceral involvement including viral pneumonia, encephalitis and hepatitis. Chronic shingles may also be found in immunocompromised hosts, particularly in those with a diagnosis of HIV infection. In patients with HIV infection, shingles is often characterised by radicular pain and itching several days before appearance of skin lesions. Those patients may have two or more dermatomes involved and recurrences of shingles cannot be quite infrequent in those patients. But visceral involvement is rarer than in other immunocompromised patients. Shingles may occur in the second half of pregnancy and usually have a mild course. However, congenital abnormalities has been described in few cases.

DIAGNOSIS: The diagnosis of shingles is usually made by history and physical examination. Exceptionally, for example in zoster sine herpete and atypical forms of shingles, virus isolation and serological tests must be used.

DIFFERENTIAL DIAGNOSIS: Some other diseases may cause similar skin lesions and rash (varicella, erysipelas, impetigo, enteroviral infections, herpes simplex infections). These diseases are excluded by using detailed history taking and physical examination, laboratory findings, virus isolation and commercially available serological tests.

THERAPY: The vast majority of immunocompetent persons with shingles should be treated only by symptomatic therapy. Predominantly it is directed toward reduction of fever and avoiding secondary bacterial skin infection in immunocompetent hosts. Acute neuritis and post-herpetic neuralgia require administration of various analgesics, even like amitriptyline hydrochloride and fluphenazine hydrochloride. Acyclovir therapy is limited to ophthal