Herpetic whitlow—also called digital herpes simplex, finger herpes, or hand herpes—is a painful viral infection occurring on the fingers or around the fingernails. Herpetic whitlow is caused by infection with the herpes simplex virus (HSV).
Infections with HSV are very contagious and are easily spread by direct contact with infected skin lesions. HSV infection usually appears as small blisters or sores around the mouth, nose, genitals, and buttocks, though infections can develop almost anywhere on the skin.
Furthermore, these tender sores may recur periodically in the same sites.
There are 2 types of HSV: herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). HSV-1 infections usually occur around the mouth, lips, nose, or face, while HSV-2 infections usually involve the genitals or buttocks.
However, HSV-1 can sometimes cause infections in the genitals or buttocks, while HSV-2 can occasionally cause infections around the mouth, lips, nose, or face.
Both types of HSV produce 2 kinds of infections: primary and recurrent. Because it is so contagious, the herpes simplex virus causes a primary infection in most people who are exposed to the virus.
However, only about 20% of people who have a primary infection with the herpes simplex virus actually develop visible blisters or sores. Appearing 2–20 days after a person’s first exposure to HSV, the sores of a primary infection last about 1–3 weeks.
These sores heal completely, rarely leaving a scar. Nevertheless, the virus remains in the body, hibernating in nerve cells.
Certain triggers can cause the hibernating (latent) virus to wake up, become active, and travel back to the skin. These recurrent herpes simplex virus infections may develop frequently (every few weeks), or they may never develop.
Recurrent infections tend to be milder than primary infections and generally occur in the same location as the primary infection.
People develop herpetic whitlow when they come into contact with areas already infected with HSV, either on their own bodies or on someone else’s body.
Usually, there is a break in the skin, especially a torn cuticle at the base of the fingernail, which allows the virus to enter the finger tissue and establish an infection. HSV-1 causes approximately 60% of herpetic whitlow infections, while HSV-2 causes the remaining 40%.
Who’s At Risk
Herpetic whitlow can affect people of all ages, of all races, and of both sexes. However, it is more common in children and in dental and medical workers. Children often contract herpetic whitlow as a result of thumb- or finger-sucking when they have a herpes infection of the lips or mouth.
Dental and medical workers may contract herpetic whitlow by touching the contagious lesions of a patient with herpes simplex virus infection.
In these groups of people—children and health care workers—herpetic whitlow is most commonly caused by HSV-1. In everyone else, herpetic whitlow is usually caused by infection with HSV-2.
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.
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.
- United States
- Annual incidence is estimated at 2.4-5.0 cases per 100,000 population.
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.
Males and females are affected equally by herpetic whitlow.
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.
Signs and Symptoms
The most common locations for herpetic whitlow include:
- Index finger
- Other fingers
Approximately 2–20 days after initial exposure to the herpes simplex virus, the infected area develops burning, tingling, and pain.
Over the next week or 2, the finger becomes red and swollen. Small (1–3 mm) fluid-filled blisters develop, often clustered together on a bright red base. The blisters usually rupture and scab over, leading to complete healing after an additional 2 weeks.
Other symptoms occasionally associated with the primary infection of herpetic whitlow include:
- Red streaks radiating from the finger (lymphangitis)
- Swollen lymph nodes in the elbow or underarm area
If a person contracts herpetic whitlow from himself or herself (autoinoculation), then he or she is likely to have a primary herpes simplex virus infection of the mouth area or of the genital area.
Repeat (recurrent) herpes simplex virus infections are often milder than the primary infection, though they look alike. A recurrent infection typically lasts 7–10 days. Recurrent herpetic whitlow is rare.
However, people with recurrent HSV infections may report that the skin lesions are preceded by sensations of burning, itching, or tingling (prodrome). About 24 hours after the prodrome symptoms begin, the actual lesions appear as one or more small blisters, which eventually open up and become scabbed over.
Triggers of recurrent HSV infections include:
- Fever or illness
- Sun exposure
- Hormonal changes, such as those due to menstruation or pregnancy
Acetaminophen or ibuprofen may help reduce fever and pain caused by the herpes simplex virus sores. Applying cool compresses or ice packs may also relieve some of the swelling and discomfort.
Because herpes simplex virus infections are very contagious, it is important to take the following steps to prevent spread (transmission) of the virus during the prodrome phase (burning, tingling, or itching) and active phase (presence of blisters or sores) of herpetic whitlow:
- Avoid sharing towels and other personal care items
- Cover the affected finger with a bandage
- Wear gloves if you are a health care provider
- Don’t pop any blisters—it may make the condition worse
Unfortunately, the virus can still be transmitted even when someone does not have active lesions. However, this is very unusual for patients with herpetic whitlow.
Emergency Department Care
Herpetic whitlow is a self-limited disease. Treatment most often is directed toward symptomatic relief.
Acyclovir may be beneficial. Studies of clinical efficacy are limited and treatment suggestions are extrapolated from data regarding response of other HSV infections.
In primary infections, topical acyclovir 5% has been demonstrated to shorten the duration of symptoms and viral shedding.
- Oral acyclovir may prevent recurrence. Doses of 800 mg twice daily initiated during the prodrome may abort the recurrence. Alternative dosing regimens may also be effective.
- Famciclovir or valacyclovir may shorten the clinical manifestations of acute occurrence.
- Topical penciclovir may be beneficial.
- Use antibiotic treatment only in cases complicated by bacterial superinfection.
- Tense vesicles may be unroofed to help ameliorate symptoms, and wedge resection of the fingernail may be used for the same purpose in cases involving the subungual space.
- Deep surgical incision is contraindicated, since this may lead to delayed resolution, bacterial superinfection or systemic spread, and complications such as herpes encephalitis.
When to Seek Medical Care
If you develop a tender, painful sore on the finger, see a physician, especially if it is not going away or if it seems to be getting worse. You should definitely seek medical attention if you have a finger sore as well as typical symptoms of oral or genital herpes.
Treatments Your Physician May Prescribe
Most herpes simplex virus infections are easy for physicians to diagnose. On occasion, however, a swab from the infected skin may be sent to the laboratory for viral culture, which takes a few days to grow. Blood tests may also be performed.
Untreated HSV infections will go away on their own, but medications can reduce the symptoms and shorten the duration of outbreaks. There is no cure for herpes simplex virus infection.
Although herpetic whitlow symptoms will eventually go away on their own, your physician may prescribe antiviral medications in order to help relieve symptoms and to prevent spread of the infection to other people:
- Acyclovir pills
- Valacyclovir pills
- Famciclovir pills
- Topical acyclovir ointment
These medications are usually taken for 7–14 days.
More severe herpetic whitlow may require oral antibiotic pills if the area(s) are also infected with bacteria.
Although it is rare, recurrent herpetic whitlow can be treated with the same oral antiviral medications:
- Acyclovir pills
- Valacyclovir pills
- Famciclovir pills
- Topical acyclovir ointment
People who experience early signs (prodromes) before recurrent infections may benefit from episodic treatment, by starting to take medication after the onset of tingling and burning but before the appearance of blisters and sores.
Very rarely, individuals may have recurrent herpetic whitlow outbreaks that are frequent enough or severe enough to justify suppressive therapy, in which medications are taken every day in order to decrease the frequency and severity of attacks.