eMedicine Specialties > Emergency Medicine > Infectious Diseases

Herpetic Whitlow

Author: Michael S Omori, MD, Attending Staff, Emergency Medicine Residency, St Vincent Mercy Medical Center; Acting Director, Pediatric Emergency Center, Mercy Children's Hospital; Clinical Assistant Professor, Department of Surgery, University of Toledo Medical Center, The University of Toledo College of Medicine
Contributor Information and Disclosures

Updated: May 27, 2009

Introduction

Background

Herpetic whitlow is an intensely painful infection of the hand involving 1 or more fingers that typically affects the terminal phalanx.¹ Herpes simplex virus 1 (HSV-1) is the cause in approximately 60% of cases of herpetic whitlow, and herpes simplex virus 2 (HSV-2) is the cause in the remaining 40%.

Adamson first described herpetic whitlow in 1909, and in 1959, it was noted to be an occupational risk among health care workers.²

Pathophysiology

As in other mucocutaneous herpetic infections, herpetic whitlow is initiated by viral inoculation of the host through exposure to infected body fluids via a break in the skin, most commonly a torn cuticle. The virus then invades the cells of the dermis and subcutaneous tissue, and clinical infection ensues within a matter of days.

In children, HSV-1 is the most likely causative agent. Infection involving the finger usually is due to autoinoculation from primary oropharyngeal lesions as a result of finger-sucking or thumb-sucking behavior in patients with herpes labialis or herpetic gingivostomatitis.

Similarly, in health care workers, infection with HSV-1 is more common and usually is secondary to unprotected exposure to infected oropharyngeal secretions of patients. This easily can be prevented by use of gloves and by scrupulous observation of universal fluid precautions.

In the general adult population, herpetic whitlow is most often due to autoinoculation from genital herpes; therefore, it is most frequently secondary to infection with HSV-2.

Subsequent to the initial exposure, an incubation period of 2-20 days is common. Although a prodrome of fever and malaise may be observed, most often initial symptoms are pain and burning or tingling of the infected digit. This usually is followed by erythema, edema, and the development of 1- to 3-mm grouped vesicles on an erythematous base over the next 7-10 days. These vesicles may ulcerate or rupture and usually contain clear fluid, although the fluid may appear cloudy or bloody. Lymphangitis and epitrochlear and axillary lymphadenopathy are not uncommon. After 10-14 days, symptoms usually improve significantly and lesions crust over and heal.

Viral shedding is believed to resolve at this point. Complete resolution occurs over subsequent 5-7 days.

As is typical of other herpetic infections, herpetic whitlow is characterized by a primary infection, which may be followed by a latent period with subsequent recurrences. After the initial infection, the virus enters cutaneous nerve endings and migrates to the peripheral ganglia and Schwann cells where it lies dormant. The primary infection usually is the most symptomatic. Recurrences observed in 20-50% of cases are usually milder and shorter in duration.

Frequency

United States

Annual incidence is estimated at 2.4-5.0 cases per 100,000 population.

Mortality/Morbidity

• Mortality related to herpetic whitlow can be presumed to be negligible.
• Morbidity is related primarily to bacterial superinfection or to iatrogenic complications due to a misguided incision and drainage resulting from incorrect diagnosis of the infection as a bacterial paronychia. These complications may include delayed resolution, increased incidence of bacterial superinfection, and, rarely, systemic spread and the development of herpes encephalitis.

Sex

Males and females are affected equally by herpetic whitlow.

Age

Toddlers and preschool children are most likely to engage in thumb-sucking or finger-sucking behavior; therefore, they are susceptible to herpetic whitlow if they have herpes labialis or herpetic gingivostomatitis.

Clinical

History

• Patients present with complaints of pain and swelling of a finger, typically with characteristic vesicular lesions. The most commonly involved digits are the thumb and index fingers.
• History of a prodrome of fever or malaise may precede the onset of symptoms by several days.
• Similar previous problems in the same digit suggest that the patient is presenting with an episode of reactivation and recurrence.
• Question patients about any recent possible exposure.
  • Health care workers with a history of exposure to oral or genital secretions are at risk.
  • Patients in the general population with a history of caring for or coming in contact with someone that has typical lesions are at risk.
  • Since autoinoculation is a common route, especially in children, ask about recent episodes consistent with herpes labialis or herpetic gingivostomatitis. In adults, inquire about a history of symptoms consistent with genital herpes.

Physical

• Involved finger is often exquisitely tender and quite edematous; however, in contrast to a felon, the pulp space usually is not tensely swollen.
• Examination usually reveals the characteristic grouped vesicular lesions or ulcers with surrounding erythema.
• Fluid within the vesicles is usually clear, although it may appear cloudy or hemorrhagic.
• Extension of infectious process into subungual space may be observed.
• Lymphangitic streaking and possibly adenopathy of the epitrochlear and axillary nodes may be found.
• Preexisting herpetic lesions may be noted in oral cavity or genitals.

Causes

• As noted, health care workers are at risk due to possibility of exposure to virus-containing secretions from their patients.
• Patients with other herpetic lesions, such as herpes labialis, herpetic gingivostomatitis, or genital herpes, are at risk due to autoinoculation.
• Immunocompromised patients are at risk for primary infection, reactivation, and possibly systemic complications.

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