A middle-aged male presents with multiple painful blisters on a erythematous base along the T3 dermatome on the trunk. Which of the following etiological agent is most likely to be implicated?

Ans. a. Varicella zoster (Ref: Roxburgh's 16th/47, 48, 84, 88: Neena Khanna 1st/214-216)An old patient presents with painful red vesicular eruption confined to T3 dermatome. Diagnosis is varicella zoster.Herpes ZosterCaused by Varicella Zoster (chicken pox) virusQ, one attack gives lifelong immunityThoracic nerves (intercoastal nerves)Q, ophthalmic division of trigeminal nerve and other spinal nerves are most commonly affectedQ.Pathology:Ballooning is characteristicQClinical 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 involve Complications: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.QHerpes simplex:Painful, cluster of vesicles on faceRecurrentTwo types:Type I: Oral lesions seen in childhoodType II: Genital lesions (is STD and carcinogenic) in young adults usually after sexual contact.