A patient presented with a vesicle on shin. Microscopy of Tzanck smear showed giant cells. Causative agent is:

Ans. b. Varicella zoster (Ref: Fitzpatrick 7/e p490-493 1873-1898; Rooks 8/e p33 14-33.22; Roxburgh 18/52-54) Vesicles on shin and giant cell on Tzanck smear suggest the diagnosis of Herpes Zoster.Tzanck SmearCytological examination of skin blistersAlter rupturing roof of the blister, the floor is scraped with a surgical blade and material is transferred on to a microscopic slide and fixed.Slides are stained with Giemsa stain. Wright's stain or toluidine blue and examined under the microscope.DisorderFindingPemphigusAcantholytic cellsQBullous pemphigoidPredominantly eosinophilQChronic bullous disease of childhoodPredominantly neutrophilsQVaricella zosterMulti nucleated giant cellsQHerpes simplex infectionMultinucleated giant cellsQToxic epidermal necrolysisNecrotic cellsHerpes ZosterCaused by Varicella Zoster (chicken pox) virusQ, one attack gives life long immunityThoracic nerves (intercostal nerves)Q, ophthalmic division of trigeminal nerve and other spinal nerves are most commonly affectedPathology:Ballooning is characteristicQTzanck smear: Multinucleated giant cellsQClinical Features:Prodrome of segmental pain begins 1-4 days before the eruptionQ, erythema and edema is rapidly followed by appearance of grouped vesicles unilateral and in a segmental distribution (MC thoracic dermatome)Q, mucous membrane within the affected dermatome may be involvedUnilateral vesicular eruption within a dermatome associated with severe painThe dermatome from T3 to L3 are most frequently involveComplications:Post-herpetic neuralgiaQ (persistent neuralgic pain)Corneal ulcer and scarring (zoster of ophthalmic division of trigeminal nerve), eye involvement is indicated when vesicles are present on the side of nose- Hutchinson's signQVariants:Ramsay Hunt Syndrome: H. zoster involving sensory branch of facial nerveQZoster opthalmicus: H. zoster involving ophthalmic division of trigeminal nerve.Q