-IBIS-1.5.0-
tx
cutaneous system
herpes zoster
diagnoses

definition and etiology

definition: an acute infection caused by reactivation of the varicella-zoster virus and involving the dorsal root ganglia; causes eruptions and neuralgia on the skin corresponding to the distribution of the affected root ganglia; also called
"shingles"

etiology: Herpes zoster is most prevalent among those 50 years and older, although it may strike at any age, particularly in immunosuppressed patients. It only affects people who have had chickenpox. Reactivation may be idiopathic or follow immunosuppression, stress, trauma including surgery, radiation etc.

signs and symptoms

signs and symptoms: prodromal stage
• pain, burning or redness of the involved area
• malaise
• fever with or without chills
• gastrointestinal disorders

After 2-5 days, the rash appears in a unilateral, dermatomal distribution usually on the thoracic area (T3-L3), face, or neck.

• erythematous base
• linear patches of grouped vesicles
• pain may be intense
• lesions stop abruptly at the midline of the body
• new crops may continue to appear for 3-5 days, after which the lesions begin to dry and crust

problem areas for herpes zoster:
• geniculate zoster: pain in the ear with transient paralysis of the face on the involved side; eruptions are visible in the external auditory canal and on the pinna, the soft palate, and the anterior pillars of the fauces

• ophthalmic herpes zoster: eruption occurs on the ophthalmic branch of cranial nerve V; if vesicles appear on the tip of the nose, then corneal involvement may occur and can lead to corneal ulcers and opacities

• recurrence rate is high

lab findings:
• (+) Tzanck smear showing multinuclear giant cells
• FAMA: fluorescent-antibody to membrane antigen
• ELISA: Enzyme-linked immuno-absorbent assay
• 40% show hypercellularity in CSF
• prolactin increased if lesions on chest wall

course and prognosis

A shingles eruption that continues for more than two weeks or becomes generalized warrants investigation for malignancy or immunologic defect. However, even in generalized zoster, fatalities are rare.

Post-herpetic neuralgia is seen in 50% of the patients over 50 years old who develop herpes zoster, and may cause excruciating pain that lasts for months or years.

differential diagnosis

• coxsackievirus infections
• pleurisy
• Bell's palsy
• trigeminal neuralgia
• herpes simplex lesions


footnotes