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Painful lesions on hand

The parents of an 8-year-old boy brought their son to a clinic because they were worried about the painful lesions on the pinkie, ring, and middle fingers of his right hand. The lesions, which had recurred monthly for the past 3 years, typically lasted a few days and then spontaneously resolved. Physical examination revealed numerous skin-colored vesicles on an erythematous base, with overlying crusting and impetiginization over the distal aspects of the fingers. The patient wasn’t taking any medication.

What is your diagnosis?


 

This patient was given a diagnosis of herpetic whitlow, or herpes simplex virus (HSV) infection of the hand. Herpetic whitlow classically has a bimodal age distribution and may be seen in children younger than 10 years of age or in adults between 20 and 30 years of age. In children, it is caused almost exclusively by HSV-1, whereas in adults it can be caused by HSV-1 or HSV-2.

HSV infection of the hand classically occurs as a result of autoinoculation following herpetic gingivostomatitis. After inoculation, the virus has an incubation period of 2 to 20 days before vesicles appear. The appearance of the lesions is associated with intense throbbing pain. Fever and systemic symptoms are rare.

Patients with herpetic whitlow will develop a single vesicle or cluster of vesicles on a single digit a few days after their skin has been irritated or exposed to minor trauma. Vesicles are typically clear in color and have an erythematous base. However, they are often superinfected with bacteria and may exhibit signs of impetiginization. The most common location of the vesicles is on the terminal phalanx of the thumb, index, or middle finger.

The diagnosis of herpetic whitlow is clinical. If the diagnosis is unclear, tests include a viral culture, serum antibody titers, a Tzanck smear, lesion specimen antigen testing, or histopathologic examinations.

The natural history of untreated, uncomplicated herpetic whitlow is complete clearance within 2 to 3 weeks. Rare complications include systemic viremia, ocular infection, nail dystrophy, nail loss, scarring, and localized hyperesthesia or hypoesthesia.

Oral acyclovir (2 g/day in 3 doses for 10 days) taken during the prodromal stage of recurrent HSV-2 herpetic whitlow has been shown to reduce the duration of symptoms from 10.1 to 3.7 days. Prophylactic use of oral acyclovir (200 mg, 4 times daily for up to 2 years) has been shown to be effective in suppressing recurrent HSV infection of nongenital skin.

The patient described here was given a 10-day course of acyclovir 400 mg orally 3 times daily and cefadroxil 500 mg orally twice daily (for superimposed bacterial infection). The lesions had completely disappeared upon follow-up 2 weeks later.

Adapted from: Ishak RS, Abbas O. Recurrent vesicular eruption on the right hand. J Fam Pract. 2014;63:33-35.

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