Herpes Simplex in Disguise: Don’t I&D That Paronychia!

This post was kindly reviewed by Dr Mark Crislip (@MarkCrislip), an ID doc who runs a great ID FOAM site called edgydoc.com.

You are working a busy shift in the “Green Zone” of your emergency department. The next patient you see is a healthy 18yM with a complaint of a painful left index finger.

You review his vital signs:
Temp 36.1, pulse 82, BP 112/65, RR 16, O2 saturation 100%

The patient shows you his finger, which looks a lot like a paronychia:

WhitlowAs you examine him, you ask for elaboration on the history. He tells you his finger has been painful for 10 days. It began 2 days after cutting it in the yard while repairing his fence. Several days later it became immensely painful and red with a blister-like area. He went to a walk-in clinic where he was prescribed Cephalexin to treat a “finger infection.” He has since not improved.

He also mentions to you that his left armpit and elbow feel sore and tender to touch. You look at the elbow and see an erythematous area over the medial aspect. His is tender with palpable lymphadenopathy in the axilla.

Are there any other questions you would like to ask him?

 

You ask if there are any other other lumps he has felt, and he mentions two lumps in his groin. When you examine him, there is palpable lymphadenopathy in the groin and a few small ulcers at the base of his penis.

Further questioning reveals that he had an encounter with a new sexual partner 2 days after the incident in his backyard. This included non-vaginal intercourse.

You connect the dots and realize this is no paronychia. This is Herpetic Whitlow!

A bit on Herpetic Whitlow:

  • HSV 1 > HSV 2
  • Involves 1 or more fingers
  • Incubation period or 2-20 days
  • Symptoms include: burning/pain, redness, low grade temp and then a cluster of vesicles
  • May get recurrences like other herpes infections of the mouth and genitalia

Who is at risk for Herpetic Whitlow?

gingivostom

Children with herpetic gingivostomatitis.

genital

Adults/adolescents with genital herpetic infection.

Who else? Health care workers/dentists/hygienists

Diagnosis:

  • Mostly a clinical diagnosis
  • Easier to identify when presents as cluster of vesicles
  • Finger infection + axillary/elbow lymphadenopathy = Whitlow
  • Confirmation can be done by gently unroofing an ulcer and performing viral culture or PCR

nodes

Pitfalls:

  • Not always straight forward diagnosis; Whitlow can mimic a paronychia: small, clear vesicles may coalesce as fluid opacifies
  • Don’t perform and incision and drainage (I&D) on Herpetic Whitlow!
  • Risks of I&D include superimposed bacterial infection or, rarely, disseminated herpes or encephalitis
  • Wear gloves!

Treatment:

  • If caught early, offer oral or topical antivirals such as acyclovir or valacyclovir. Benefit is limited thereafter.
  • Screen, if appropriate, for other STIs.
  • Oral antiobiotics only if evidence of secondary bacterial infection.
  • Advise the patient to keep the infected finger away from the eyes to avoid HSV keratitis.

antivirals

Case Resolution:

You tell the patient that you believe his painful finger is due to an infection by the herpes virus that seeded the abrasion sustained while working in the yard. Unfortunately, the benefit of antiviral medications is minimal at this point. As well, you don’t expect him derive benefit from the oral antibiotic he has been taking (since there is no evidence of superimposed bacterial skin infection). You advise keeping the finger covered to avoid spread and offer testing for other STIs. One of the genital lesions is unroofed and swabbed. Several days later the culture returns positive for HSV-2.

References:

This post underwent minor revisions on Nov 18, 2014. Originally posted on Nov 17, 2014.

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