What is Herpetic Whitlow?
The herpes simplex virus (HSV) is a common virus usually passed on during childhood through direct touch. The virus most commonly infects the mouth (known as HSV-1) or the genitals (known as HSV-2). Occasionally, the virus can infect the fingertip, causing pain, swelling, redness, and blisters in a condition called herpetic whitlow. It’s important to correctly identify this condition because it can look very similar to another finger infection called paronychia, but the treatments for these two conditions are very different.
What Causes Herpetic Whitlow?
Herpetic whitlow is a condition caused by the herpes simplex virus. There are two types of this virus, type 1 and type 2. The initial infection happens when the virus enters the body through broken skin. This can occur either through direct contact with someone else who has the virus (exogenous) or by self-contamination (autogenous).
Sometimes, even if the virus seems to have gone away, it can come back after some months or years. This is known as recurrent infection. So, if a person had herpetic whitlow in the past, they could get it again due to the reactivation of this latent or ‘sleeping’ virus.
Risk Factors and Frequency for Herpetic Whitlow
This type of infection can occur in people of any age. It is more likely to affect children who suck their thumbs and healthcare professionals, such as medical or dental workers, who handle patients’ mouth areas without wearing gloves. Dental hygienists and respiratory therapists are particularly susceptible. Interestingly, herpetic whitlow can also arise in athletes involved in wrestling and young people exposed to genital herpes. The rate of occurrences has been found to be 2.4 cases per 100,000 people annually.
- The infection can occur in people of all ages.
- It’s particularly common in children who suck their thumbs and healthcare professionals who come into contact with patient’s mouths without gloves.
- Dental hygienists and respiratory therapists are often affected.
- Athletes involved in contact sports like wrestling and young people exposed to genital herpes can also contract the infection.
- The incidence is 2.4 cases per 100,000 people per year.
Signs and Symptoms of Herpetic Whitlow
Herpetic whitlow is a condition usually diagnosed based on visible signs and symptoms. People with this condition may recall suffering a minor injury, particularly to the nail cuticle, even though many won’t remember any specific incident. This condition is commonly associated with exposure to the herpes virus, which can be contracted through skin-to-skin contact with cold sores or genital herpes. If a person has a primary oral herpes infection, it may suggest they got herpetic whitlow by transferring the virus from their mouth to their hand.
At the start of the infection, patients often feel pain and a tingling sensation in the affected finger even before there are any noticeable changes to the skin. This is typically followed by tenderness, redness, and swelling in the area, with small liquid-filled blisters appearing mostly around the tip and on the sides of the finger. While the infection usually affects only one finger, in rare instances, it can spread to multiple fingers. These blisters often merge and form large, honeycomb-like fluid-filled sacs. If the nail bed is involved, bleeding or purple-red discoloration can occur which could be extremely painful. Additional symptoms may include fever, swollen lymph nodes in the armpit or elbow, and, on rare occasions, swelling of the hand and forearm. The latter is mostly likely due to a secondary bacterial infection.
The fluid in the blisters starts off clear but can become cloudy or even bloody over time. If a bacterial infection sets in, pus can also be present. For patients with weak immune systems, like those with AIDS who have a very low CD4 cell count, the affected skin areas can even ulcerate and die off.
- Pain and tingling sensation in the finger before any visible changes to the skin
- Tenderness, redness, and swelling
- Small blister formation, primarily around the tip and sides of the finger
- Blisters merging and forming large, honeycomb-like fluid-filled sacs
- Potential involvement of the nail bed leading to bleeding or purple-red discolouration
- Additional symptoms may include fever and swollen lymph nodes
- Rare possibility of swelling of the hand and forearm, primarily due to secondary bacterial infection
- The blister fluid becoming cloudy or blood-stained over time
- In immunocompromised patients, possible ulceration and tissue death
Testing for Herpetic Whitlow
The diagnosis of herpetic whitlow, a skin infection usually involving a finger or thumb, is typically based on how the skin looks and the patient’s medical history. When the diagnosis isn’t clear from these factors, there are a few tests for the herpes simplex virus (HSV), which is responsible for herpetic whitlow.
One testing method involves taking a sample from the base of the blisters (vesicles) after removing the top layer. This method, known as a viral culture, can predict the presence of HSV about half the time overall. The virus is most concentrated in the vesicles during the first 24 to 48 hours after they appear, creating about an 89% chance of a positive result.
PCR testing, a method that allows for the detection of even small amounts of the HSV virus, is much more sensitive than a viral culture. Other tests that may be used, though less common, include serology, which detects antibodies in the bloodstream, and direct fluorescent antibody testing, which identifies the virus under a microscope.
A Tzank test is another choice, which scrubs the floor of a blister, paints the sample, and then checks for abnormal cells that look like “balloons”. This test has about a 70% chance of correctly identifying the disease.
If your symptoms don’t follow typical patterns or you frequently get the infection, your doctor might also recommend an HIV test. This virus can weaken your immune system and make you more susceptible to other infections, including HSV.
Treatment Options for Herpetic Whitlow
Treating herpetic whitlow, a viral infection causing painful sores on the fingers, primarily involves managing the symptoms and preventing a secondary bacterial infection. The infection generally resolves on its own within 2 to 4 weeks if the patient has a healthy immune system. It’s important to note that draining the sores should be avoided as it doesn’t provide any relief from symptoms. In fact, it can potentially lead to viremia (presence of viruses in the blood) and an additional bacterial infection. However, there have been reports of notable pain relief after removing a portion of the affected nail to ease pressure from blisters along the nail bed.
While specific studies on herpetic whitlow are few, antiviral medications have been demonstrated to reduce the duration of symptoms and decrease the number of days the virus can be found in cultures. These benefits are especially pronounced if the antiviral treatment is started within 48 hours from when symptoms begin. For recurring instances of herpetic whitlow, long-term antiviral treatment may help prevent new outbreaks. It’s not yet clear whether one type of antiviral medication – such as acyclovir, famciclovir, or valacyclovir – is more effective than another for this condition. If a secondary bacterial infection develops in the affected finger, antibiotics may be necessary.
What else can Herpetic Whitlow be?
Herpetic whitlow, a type of herpes infection on the fingers, can sometimes be mistaken for other conditions. These can include:
- Paronychia – a bacterial abscess located in the skin fold around the nails
- Bacterial felon – an abscess in the fleshy part of the finger
The vesicles, or blisters, associated with herpetic whitlow are often pale-yellow, which can lead people to think it’s a different kind of infection. If a doctor was to make an incision or use a needle to draw out fluid, they would not find the kind of pus associated with a bacterial infection.
Other possible diagnoses might also include herpes zoster infections. These would affect the entire length of the nerve supplying the skin (dermatome) of the hand. More rarely, the person may have an infection caused by Neisseria gonorrhoeae, a sexually transmitted bacterium, or Mycobacterium marinum, a bacterium found in water.
What to expect with Herpetic Whitlow
Herpetic whitlow, a type of skin infection, usually gets better on its own within 2 to 4 weeks when it’s the first occurrence. After the most severe phase, the discomfort starts to lessen, and the blisters begin to dry and form a scab. Generally, the pain goes away in about 14 days, and any remaining changes to the skin continue to heal after that. Usually, fingers and nails heal completely without any long-term problems, although there have been some reports of lasting scarring, numbness, and extra sensitivity.
It’s important to note that in 30% to 50% of cases, the infection can come back because the virus remains in the sensory nerves.
Possible Complications When Diagnosed with Herpetic Whitlow
Herpetic whitlow, a skin infection caused by the herpes simplex virus, is often mistaken for other infections such as bacterial paronychia or felon. This misunderstanding can lead to treatments that increase the chance of additional bacterial infections, spread of infectious agents throughout the body, and the potential development of herpes encephalitis – a serious condition where the brain becomes inflamed.
Other complications of herpetic whitlow are:
- Scarring
- Numbness
- Increased sensitivity
- Spread to the eyes
- Recurring infections
Preventing Herpetic Whitlow
Patients need to know that this virus can move to other parts of their body or even spread to other people through direct touch. They can still pass the virus to others until the rash or skin sore has completely healed. So, it’s crucial for patients to wear something like gloves to act as a protective barrier. It’s also important to know that the virus may come back with a chance of about 30% to 50%. To manage this, patients are advised to stick to their prescribed medicines and contact their doctor if they see signs of an additional bacterial infection over their current virus.
