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FINDINGS: The vesicle looks like a teardrop on a red base. Unlike smallpox vesicles, they collapse when punctured. Complications of chickenpox include pneumonia, encephalitis, and bleeding. Herpes zoster occurs in patients previously infected with the chickenpox virus. The reactivation of the dormant varicella virus occurs in the dorsal root ganglion. Some patients develop permanent pain (postherpetic neuralgia) in the affected dermatome. [CCDM, p. 94-9] The lesions appear as successive crops over 2 -4 days so that all stages of development (papules, vesicles, pustules, and scabs) are visible. Lesions are usually about 5 mm in diameter, but may be as large as 13 mm. [PPID, p. 1782-4] Herpes zoster may cause conjunctivitis, keratitis, uveitis, and, rarely, cranial nerve palsies. [Guerrant, p. 1557-9] PREVENTION: Consider administering chickenpox vaccine within 3-5 days of exposure. VZIG is available for immunodeficient patients and should be administered within 96 hours of exposure. [CCDM, p. 98-9] TREATMENT: The antiviral drugs vidarabine and acyclovir are treatment options. [CCDM, p. 98-9] EPIDEMIOLOGY: Chickenpox patients are contagious beginning about 2 days prior to onset of the rash until all vesicles have crusted (usually about 5 days after onset of the rash). [CCDM, p. 96] |