Applied Evidence

How best to approach these acute hand infections

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Antimicrobial therapy is not straightforward with the 4 infectious conditions reviewed here. Combination therapy at the start must usually be tailored once an organism is known.


› Obtain a sample of pus for Gram stain and for ­cultures of aerobic and ­anaerobic organisms, ­acid-fast ­bacilli, and fungi. A

› Use antibiotics as an ­adjunct to ­elevation and splinting in flexor ­tenosynovitis to ­improve range-of-motion outcomes. A

› Notify your ­microbiology lab to enrich cultures with 10% CO2 to isolate Eikenella corrodens. A

› Consider ­prescribing ­acyclovir, f­amciclovir, or valacyclovir for ­herpetic whitlow. B

Strength of recommendation (SOR)

A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series



Hand infections, if not treated properly, can cause severe chronic morbidity. The conditions I review here range from superficial to deep seated: herpetic whitlow located in the epidermis; felon in subcutaneous tissue; pyogenic flexor tenosynovitis (FTS) in the tendon sheath; and human bite infection at any level including possibly synovium and bone.

Superficial infections usually respond to nonsurgical management. However, antimicrobial therapy is not straightforward. There is no single regimen that covers all possible pathogens. Combination therapy must usually be started and then tailored once an organism and its susceptibility are known. Subcutaneous, tendon sheath, synovial, and bone infections frequently require surgical management.

Herpetic whitlow

Herpes simplex virus type 1 (HSV-1) is common, with as much as 90% of the population exposed by 60 years of age.1 Initial infection usually occurs in the oropharynx and is known as a fever blister or cold sore. However, HSV-1 also can cause herpetic whitlow, a primary infection in the fingertip in which the virus penetrates the subcutaneous tissue, usually after a breakdown in the skin barrier either from infected saliva or the lips of an infected individual.1

What you’ll see. The lesion is characterized by pain, swelling, erythema, and nonpurulent vesicle formation ­(FIGURE 1). The condition is usually self-limiting, with the inflammation resolving spontaneously, leaving normal healthy skin within 1 to 2 weeks. Herpetic whitlow is an occupational hazard for medical, nursing, paramedical, and dental personnel, and standard precautions should be used when handling secretions (Strength of Recommendation [SOR]: A).2

Herpetic whitlow is usually treated conservatively

Herpetic whitlow is distinguished from a felon by its formation of vesicles, lack of a tense pulp space, and serous, not purulent, drainage.

Reactivation of HSV-1 (and HSV-2) is common, with a prodrome of a “tingling sensation” and subsequent blister formation in the same location as the previous infection. It can cause pain and discomfort and may render the individual unable to perform usual activities.1,3 This lesion is often confused with bacterial (pyogenic) infections of the pulp of the finger or thumb (felon).1 Herpetic whitlow can be distinguished from a felon by its formation of vesicles, lack of a tense pulp space, and serous, rather than purulent, drainage. Scarring is not associated with herpes infection because penetration is limited to the epidermal area. Superimposed bacterial infection can be mistaken for an abscess (felon) and lead to unnecessary incision and drainage, causing associated morbidity and potential scarring in the affected area.1

How it’s treated. Treatment of herpetic whitlow is usually conservative, and topical application of acyclovir 5% appears to be beneficial (SOR: C).4 Two studies also suggest that oral acyclovir is beneficial for herpetic whitlow and may reduce the frequency of recurrence.5,6 Controlled studies in the use of acyclovir for herpetic whitlow have not been conducted. Despite a lack of direct evidence, acyclovir, famciclovir, and valacyclovir are accepted therapies for herpetic whitlow (TABLE 17) (SOR: B).6,8

Recommended dosages for commonly used antivirals


A felon is a closed-space infection affecting the pulp of the fingers or thumb. The anatomy of the finger is unique in that there are multiple septa attaching the periosteum to the skin, thereby creating several closed spaces prone to develop pockets of infection.

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