Purulent inflammation of a tip of a finger or a toe due to infection by the herpes simplex virus (HSV) is called whitlow, herpetic whitlow, or whitlow finger. It can occur when there is contact between a broken skin layer and body fluids infected with HSV and often affects the fleshy portions of the fingertips. A form of melanoma closely resembles whitlow and is called melanotic whitlow.
Whitlow presents as pain and swelling of a finger following several days of viral incubation. There may also be associated burning, tingling, or itching sensation of the finger and the presence of vesicular lesions in the affected area. These vesicles usually contain serous fluid and may become purulent only if bacterial superinfection occurs.
The appearance of a painful swollen finger may be preceded for several days by a prodrome of fever, fatigue, or malaise. This represents the incubation period of HSV when the virus is still multiplying and is yet unable to produce a full-blown infection.
The pain and swelling may abate spontaneously after 10 -14 days, and the vesicles start to form crusts and eventually heal.
The most specific diagnostic test for herpetic whitlow is viral culture of the vesicle fluid. Tzanck test may be performed by scraping the vesicles and spreading the samples on a glass slide, where they are stained with Giemsa and examined under a microscope. However, the Tzanck test carries a low sensitivity. Other definitive tests include DNA hybridization, polymerase chain reaction, or immunofluorescent microscopy.
HIV testing is recommended for patients with recurrent infections and atypical presentations of whitlow  .
Whitlow does not require any treatment and will resolve spontaneously since it is a self-limited disease. Treatment with antiviral drugs such as topical acyclovir or penciclovir may be applied in order to decrease the duration of the disease, reduce the risk of spreading the virus to other areas of the body, lower the risk of bacterial infection, or decrease viral shedding. Oral acyclovir may also be used to prevent recurrence, and famciclovir or valacyclovir may reduce the duration of clinical recurrence.
Surgical techniques to unroof a vesicle or wedge resection of a nail in subungual infections may be performed in order to provide symptom relief. However, deep surgical incision should not be performed, as this can cause bacterial superinfection or viral encephalitis if the virus spreads through the systemic circulation.
Since melanotic whitlow is a malignant lesion and not an infection, its treatment is similar to those of other forms of skin malignancies. Wide local excision with at least 1-2 cm margins is recommended, whereas extensive or deep lesions should be managed by amputation of the affected digit.
Herpetic whitlow may resolve spontaneously even when left untreated. However, the use of antiviral creams may lessen the symptoms and shorten the course of the disease. This condition does not usually cause complications unless secondary bacterial infection occurs, causing a longer course and additional treatment. In some cases, viral encephalitis may also develop  .
It is believed that melanotic whitlow carries a similar degree of malignancy compared to other types of melanoma . However, some evidence suggests that it may have a relatively better prognosis  . Treatment is ineffective and of no clinical use in cases of metastasis.
Herpetic whitlow is caused by direct transfer of HSV-1 or HSV-2 from herpetic lesions to a finger with a broken skin barrier. This can happen when a person touches a cold sore or genital herpes lesions, allowing the herpes virus to invade the damaged skin layer. The source of the virus may be from the same person (autoinoculation) or another person infected with HSV. Whitlow commonly develops in patients with weakened immune systems since this is a condition that allows latent HSV in the neurons to reactivate.
The estimated incidence of whitlow in the United States is approximately 2.4 to 5 cases per 100,000 population, with no predilection for gender. Toddlers and preschool children are more commonly affected since their age group has a tendency to practice thumb-sucking. In terms of HSV serotypes, HSV-1 infection is more prevalent in medical personnel whereas HSV-2 has a greater tendency to infect the general population . Herpetic whitlow may either be an initial or recurrent infection due to the capacity of HSV to remain latent in the neurons of the peripheral ganglia   . However, the rate of recurrence is variable  , with some patients experiencing more recurrence than others.
Melanotic whitlow accounts for approximately 2.9 to 15% of all melanomas  , and evidence suggests that around 9% of melanotic whitlow originates in the subungual space .
Herpetic whitlow occurs when HSV is inoculated onto a damaged skin barrier through infected bodily fluids. After inoculation, the virus penetrates the deeper skin layers and the subcutaneous tissue, causing clinically significant infection after an incubation ranging from 2-20 days.
Several age groups and patient populations may be affected by the two HSV serotypes. Younger age groups tend to be infected with HSV-1 transmitted by autoinoculation (through thumb-sucking) from herpetic lesions in the mouth such as herpetic gingivostomatitis or herpes labialis. Whitlow in adults are also commonly caused by autoinoculation. However, the virus most often involved in the transmission of the disease is HSV-2 from genital herpes. Healthcare workers are most often infected by HSV-1 resulting from unprotected contact with infected oropharyngeal or genital secretions from patients.
The primary infection with HSV usually produces a highly symptomatic disease. Once HSV penetrates the skin, it can migrate to the Schwann cells and peripheral ganglia and lies dormant until certain conditions allow it to be reactivated. Recurrence of herpetic whitlow is generally milder, less symptomatic, and has a shorter duration than the initial infection in around 20-50% of patients.
Proper handwashing  and the use of gloves among medical personnel may decrease the risk of herpetic whitlow. Healthcare workers with active disease should avoid direct contact with patients, especially the immunosuppressed, neonates, pregnant women, transplant patients, or patients with severe burns  . Patients with recurrent whitlow should undergo evaluation to detect conditions that affect the immune function.
Whitlow, whitlow finger, or herpetic whitlow is an infection affecting the fingers, usually on the terminal phalanx , caused by herpes simplex virus (HSV). It is characterized by painful, itchy, erythematous inflammation of the fingers and may be accompanied by blisters at the site of infection. A serious infection should be suspected in the presence of fever, red streaks on the hands or the arms, and significant lymphadenopathy.
Since the transmission of this condition relies on contact of HSV-infected body fluids with broken skin, herpetic whitlow is considered as an occupational hazard among healthcare workers . It can be caused by both serotypes of HSV, with HSV-1 accounting for 60% of cases and HSV-2 in the remaining 40%.
Although antiviral medications may be given to reduce the symptoms and duration of whitlow, it usually resolves spontaneously after 2 to 3 weeks even without medication. However, HSV may remain dormant or latent in the neurons and may become active in immunodeficient states such as extreme stress or the presence of a previous or existing infection. The same treatment may be given if the whitlow reappears.
A form of melanoma called melanotic whitlow may sometimes be mistaken for herpetic whitlow and is responsible for many misdiagnosed and mistreated cases . Melanotic whitlow differs from herpetic whitlow in the sense that the affected area is hyperpigmented and has a malignant course.
Herpetic whitlow is a disease caused by the herpes virus. It usually affects the fingertips and causes pain, redness, or swelling of the affected fingers, as well as itching or tingling sensations. Blisters with clear fluid may also form.
This disease is transmitted through contact of broken skin with fluids containing herpes virus. Children with cold sores may get this disease if they are fond of thumb-sucking. Persons with genital herpes and healthcare workers may also develop this disease.
A light dressing should be applied on the affected area to prevent spread of the infection. Avoid wearing contact lenses or rubbing your eyes as they may be infected with the herpes virus. Analgesics such as paracetamol or ibuprofen may be taken for pain relief. It is important to note that herpetic whitlow is a self-limited disease, which means that it will resolve spontaneously after 2 or 3 weeks even without medication.
A form of skin cancer called melanotic whitlow has a similar appearance as whitlow except that the affected area of the finger exhibits a darker color (hyperpigmentation). The treatment for this condition is different from herpetic whitlow. Since this is a form of skin cancer, excision of the whole lesion is the most effective treatment. The outcome depends on early detection and correct diagnosis of this condition.