Herpes Zoster Overview

Herpes Zoster is a localized disease caused by varicella-zoster virus, mainly found in adult, characterized by radicular, unilateral pain and groups of vesicles distributed according to the dermatome innervated by one sensory nerve ganglion.

ETIOLOGY. Zoster is caused by the same virus that causes chickenpox. Trauma of the nerve root is believed to play a role in development of some cases of shingles. “Nervousness” plays little if any role.

Shingles is a common viral disease characterized by the appearance of several groups of vesicles distributed along a cutaneous nerve segment. Zoster and chickenpox are caused by the same virus. Susceptible children or rarely adults who are exposed to cases of zoster may develop chickenpox.

PRIMARY LESIONS. Multiple groups of vesicles or crusted lesions appear.

SECONDARY LESIONS. Bacterial infection with pustules occurs, rarely progressing to hemorrhagic gangrenous ulcers and scarring.

DISTRIBUTION. Unilateral eruption follows a nerve distribution, frequently in the thoracic region, the face, the neck, and, less frequently, the lumbosacral area and elsewhere. Eye involvement can be serious. Bilateral involvement of the body is rare but not fatal, contrary to the old wives' tale, and still predominates on one side of the body.

Clinical Symptoms

1. Prodormal Stadium. Itches and pain over the infected dermatome accompanied by fever, malaise, and headache.
2. Eruption Stadium. At first, papules or plakat in the form of urticaria will appear. After 1-2 days, groups of vesicles will appear over erythematous skin whereby the skin in between the groups remains normal. The stages of the lesions within a group ae the same whereas those of between groups are different. The location of the lesions follows the dermatome and unilateral. The lesions usually do not cross over the contralateral side.
3. Crustation stadium/ Vesicles become purulent and undergo crustation which then detach from the skin in 1-2 weeks. Post-herpetic neuralgia is common especially in elderly , which causes temporary paresthesia lasting for months.

SUBJECTIVE COMPLAINTS. Pain of a neuritic type can precede the eruption and, if in the abdominal area, can lead to erroneous diagnoses and surgical procedures. The common simple pain of young persons with shingles is readily treated and soon disappears. On the other hand, the severe, true post-herpetic pain of older patients can be very serious. To evaluate critically the therapeutic response to the many agents said to relieve this severe pain, a nerve-distribution pain should not be labeled as the true post-herpetic type unless it has been present for over 30 days. If this strict criterion is adhered to, many newly proclaimed treatments for such pain are found to be of limited value, but usage is common considering their low risk of side effects. For the best results use early in the course of disease.

LABORATORY FINDINGS. A cytodiagnostic test (Tzanck test) is positive for multinucleated giant cells. A culture or a polymerase chain reaction can be done.

Differential Diagnosis

1.     Dermatitis contacta allergica
2.       Varicella
3.       Herpes Simplex
4.       Disease with bulla, e.g pemphigus vulgaris
5.       Duhring’s herpetiformis dermatitis
6.       Bullous pemphigoid.

Complications
1.       Secondary infections
2.       Post-herpetic neuralgia
3.       Kerato-conjunctivitis in ophtalmic herpes zoster
4.       Ramsay-Hunt Syndrome
5.       Zoster Generalisata: zoster accompanied by varicella.