An Overview of Herpetic Whitlow

Whether you or a loved one has experienced the pain and frustration of herpetic whitlow, or believe you may be suffering from such this condition, be assured that this viral infection is common and self-limited.

By learning about herpetic whitlow, you and your healthcare provider can hopefully recognize the infection promptly. Even more importantly, perhaps you can prevent it from occurring in the first place.

Symptoms

The symptoms of herpetic whitlow resemble that of other herpes infections. There is a red, blistering rash present, along with pain and sometimes, flu-like symptoms.

Rash

Herpetic whitlow occurs as a single vesicle (a fluid-filled sac or blister that forms beneath the skin) or multiple vesicles on one finger. Rarely, multiple fingers are involved. The vesicles of herpetic whitlow are generally clear or slightly yellowish in appearance and lie over a red base on the finger. Mild swelling surrounding the rash on the finger is also common.

Over a twelve-day period or so, the vesicles group together ("cluster") and eventually morph into shallow sores or ulcers that dry up, crust, and peel off the skin. Sometimes, the vesicles spread into the nail bed, leading to bleeding or bruising around the nailbed.

Pain and Associated Symptoms

In addition to the vesicle or vesicles on the finger, people experience burning and/or tingling pain within the affected finger. Interestingly, this pain (similar to other herpes infections) often precedes any skin changes. Some people also experience fever and swollen lymph nodes in the armpit and/or upper limb.

Recurrence

It's important to understand that 30% to 50% of the people with herpetic whitlow experience a recurrence of the infection, often triggered by one of the following factors:

• Illnesses with a fever
• Overexposure to sunlight
• Physical or emotional stress
• Suppressed immune system
• Menstruation

Recurrent infections occur when the herpes simplex virus—which lies dormant in a nerve bundle—emerges and causes symptoms. Like other herpes infections, the good news is that recurrent infections are often milder and last a shorter time.

Complications

While it's uncommon to develop complications from herpetic whitlow if they do occur, they usually include one or more the following:

• Scarring
• Nail damage
• Numbness
• Skin hypersensitivity

Rarely, herpetic whitlow causes a disseminated HSV infection—when the virus has spread from its local site to other areas of the body, like the brain or spinal cord. This is a very serious complication and requires hospitalization.

In addition to the vesicle or vesicles on the finger, people experience burning and/or tingling pain within the affected finger. Interestingly, this pain (similar to other herpes infections) often precedes any skin changes. Some people also experience a fever and swollen lymph nodes in the armpit and/or upper limb.

Causes

Herpetic whitlow is a viral infection of the finger caused by the herpes simplex virus (HSV).

A person may develop a herpetic whitlow if broken skin on a finger (usually trauma-induced) comes into direct contact with HSV sores or blisters (such as cold sores or genital herpes) on someone else's body or on their own body.

What happens biologically is that once the skin is broken and HSV enters the body, the virus infects human epithelial cells, replicates, and symptoms occur.

While anyone (children and adults) can get herpetic whitlow, there are certain factors that increase a person's chances of becoming infected.

Some of these factors include:

• Having a weakened immune system (such as having HIV or cancer that affects the bone marrow)
• Taking a medication that suppresses your immune system (for example, a corticosteroid or chemotherapy)
• Engaging in occupational hazards, such as not wearing gloves as a dentist, healthcare provider, or another healthcare practitioner

Diagnosis

The diagnosis of herpetic whitlow is made by visualization of the characteristic rash by a healthcare provider. To confirm the diagnosis (especially if the infection is severe or the patient is pregnant or has a weakened immune system), your provider may perform one of several tests.

Viral Culture

A viral culture entails opening the sore with a sterile scalpel blade or needle, rubbing the sore with a sterile swab to soak up the fluid from the vesicle base, placing the swab in a container, and sending it off to a laboratory.

Once in the lab, the swab contents will be swiped onto a dish where they can be monitored for the growth of the herpes virus. Typically, it takes one to four days for results from a viral culture to be reported back to your healthcare provider. A positive result means that the herpes virus grew within the laboratory dish.

Blood Test

Sometimes, instead of a viral culture—like if your sore cannot be properly swabbed or you are concerned you were exposed to herpes (but have no symptoms)—your practitioner may opt for a blood test to look for antibodies to the herpes virus.

Bear in mind, a blood test is not as sensitive (meaning its effectiveness for ruling in a diagnosis) as viral culture. In addition, it takes about one to two weeks for your body to produce antibodies against the herpes virus, once infected. With that, it's best to wait a few weeks after possible exposure to avoid obtaining a false-negative.

Tzanck Smear

Another test, called a Tzanck smear, is not specific for the herpes virus, but it is inexpensive and rapid. During this test, a healthcare provider will use a small blade to unroof or open the sore, scrape its base, and then smear onto a glass slide. After staining the slide (called the Wright-Giemsa stain), it can be examined under a microscope for "Tzanck cells," which are "multinucleated giant cells."

Keep in mind though, these cells do not exclusive occur with the herpes simplex virus. They may occur with other infections, like varicella (chickenpox), herpes zoster (shingles), and cytomegalovirus (CMV).

Treatment

The treatment of herpetic whitlow typically entails simple, self-care measures, as the infection will heal on its own within two to four weeks. Sometimes, though, medication is recommended, especially if the infection is severe or your immune system is suppressed.

Self-Care Strategies

To ease the inflammation and associated swelling and pain of herpetic whitlow, your healthcare provider may recommend elevating your finger and taking a nonsteroidal anti-inflammatory drug (NSAID), like ibuprofen. Cool compresses applied to the finger can also be soothing.

In order to prevent a bacterial secondary infection, it's important to gently clean the affected area on your finger every day. After cleaning, apply a dry dressing over the rash. The dressing will not only prevent bacteria from getting into the sore(s) but will also prevent the spread of the herpes virus.

In addition to dry dressing, your practitioner may also recommend wearing a protective glove to further decrease the risk of transmission.

Antiviral Medications

In addition to self-care strategies, your healthcare provider may recommend an anti-viral medication. The following anti-viral medications are available by prescription:

• Zovirax ointment (topical acyclovir)
• Zovirax (oral acyclovir)
• Valtrex (valacyclovir)
• Famciclovir (Famvir)

Rarely would an antiviral, like acyclovir, be given through the vein (called intravenous acyclovir). This is generally only done to treat a disseminated HSV infection or if a person has a severely weakened immune system. 

Suppressive Therapy

Although not well studied specifically for herpetic whitlow, in some instances, your healthcare provider may recommend taking a daily antiviral medication to prevent recurrent infections.

While not FDA-approved for herpes infections, suppressive therapy may decrease the number of herpetic whitlow recurrences and decrease viral shedding (the release of the herpes virus from the affected human cells).

A Word From Verywell

As a final tidbit, if you suspect you or a loved one may have a herpetic whitlow, be sure to see a dermatologist or primary care provider with experience in recognizing this infectious skin condition.

Besides the fact that you may need a prescription antiviral drug, herpetic whitlow can mimic other infectious conditions, like a bacterial infection of the finger, which involves a distinct treatment plan.