• Pain and swelling: Patients with herpetic whitlow have swollen fingers with extreme pain. Common digits involved in this disease are thumb and the index finger. 
• Fever and malaise.
• The involved digit appears tender, and edematous.
• Vesicular lesions or ulcers, which are grouped together, with surrounding erythema, are seen. The fluid in these vesicles is often clear.
• In some cases, adenopathy of the axillary nodes may be seen. 
• There may be herpetic lesions in the oral or genital areas [6][7] [8].

Diagnosis of herpetic whitlow is clinical. The digit affected by herpetic whitlow can be identified by the characteristic lesions. In children, concurrent gingivostomatitis, and among adults, presence of occupational risk factors or concurrent genital infection suggests strong diagnosis.

Tzanck test, viral cultures, DNA hybridization and antibody testing are some of the known tests. Cost-effective and popular diagnostic tools for herpetic whitlow are polymerase chain reaction (PCR) and immune-fluorescent microscopy. Recurrent infections of herpetic whitlow, unusual locations or/and atypical presentation suggests an immunedeficient condition. HIV testing is therefore recommended in such patients [9].

Though herpetic whitlow is a self-limiting condition, treatment is aimed to relieve the patient from the symptoms. Topical acyclovir or penciclover shortens the duration of symptoms, while oral acyclovir prevents recurrence. For acute occurrence, famciclover and valacyclovir are also beneficial. Antibiotic treatment is prescribed in cases of bacterial superinfection [10] [11].

Since herpetic whitlow is a self-limiting condition, the prognosis is good. Unless complicated, the disease can be contained by clinical course with proven drug therapy. Spontaneous resolution within 3-4 weeks is observed in patient with herpetic whitlow [4] [5].

Complications

HSV infection can spread throughout the body. Weakened immune system makes the HSV infection severe, causing complications [1].

Two most important viruses that can cause this disease are herpes simplex virus 1 (HSV-1) and herpes simplex virus-2 (HSV-2). 60% and 40% of all the herpetic whitlow infections are caused by HSV-1 and HSV-2 respectively. Immunocompromised patients, health-care professionals and patients with herpetic lesions (due to autoinoculation) are at a higher risk of infections with these viruses [3].

Approximately 2.4 to 5 cases every 100,000 population have been reported for herpetic whitlow in USA. Though mortality with this disease is almost negligible, morbidity is attributed to the bacterial superinfection as well as iatrogenic complications.

Both male and female are equally affected by this condition. Toddlers and children are more likely to be affected by HSV-1 and HSV-2 viruses, as they are engaged in thumb or finger sucking.

Herpetic whitlow is caused by inoculation of the virus. Once the virus enters and invades the cells of the dermis, clinical infection ensues.

• In children, as the infection involves finger sucking, the autoinoculation by HSV-1 from oropharyngeal lesion is common. 
• In health care workers, inoculation with HSV-1 occurs secondary to the unprotected exposure. Prevention of such infections is possible with the use of gloves. 
• In adults, the source of autoinoculation is genital herpes, and thus the common cause of infection is HSV-2. 

The incubation period of the disease is 2 to 20 days. Initial symptom of the disease is pain and burning or tingling of the infected digit, followed by erythema, and edema. It leads to the formation of 1-3 mm grouped vesicle, which may ulcerate or rupture and contain clear fluid, (which may be cloudy or bloody).

After 10 to 14 days, there may be improvement in the symptoms of the condition. Viral shedding and complete resolution generally occur after 5 to 7 days. Herpetic whitlow is characterized by a primary infection followed by a latent period and subsequent recurrence (in 20-50% of cases) [1] [2].

Avoiding the exposure to HSV can prevent herpetic whitlow. Having no contact with patients with known infections is important. Health care workers must wear gloves, and wash his hands regularly and thoroughly. Infection by the HSV-1 and HSV-2 can spread to different parts of the body by touching the infected area, sharing towels, contact lenses or flannels. Children must be discouraged to suck the infected finger/thumb.

The painful infection of the hand (distal phalanx), that involves one or more fingers is known as herpetic whitlow. Adamson was the first person to describe the condition in 1909.

In 1959, occupational risk among the health care workers was also included as an important risk factor for this condition. Health care workers and immunocompromised patients are at a higher risk, as they are often exposed to the virus-containing secretions from the patients [1] [2].

Definition

Infection of the digit (thumb and index fingers are common), which appears as a whitlow or infection by the herpes virus is known as herpetic whitlow. Patients with this condition are often presented with severe pain, and swelling. 

Causes

Herpetic whitlow is caused by the two different types of herpes virus namely HSV-1 or HSV-2. Six in every 10 and four in every 10 patients with herpetic whitlow is caused by HSV-1 and HSV-2 respectively.

Symptoms

After approximately 20 days after exposure to the virus, the infected area starts burning, with a tingling sensation and pain. The finger may become red, with appearance of fluid-filled blisters. Complete healing of the condition within 2 weeks is common. Some of the other common symptoms of the condition are fever, swollen lymph nodes and red streaks on the finger. Recurrent infection lasts for 7-10 days. Triggers of the recurrent herpetic whitlow are fever, stress, surgery, exposure to sun or hormonal changes.

Diagnosis

HSV infection can be diagnosed by the serological tests, direct fluorescent antibody test from the cells from the lesion and viral culture. 

Treatment

Usually herpetic whitlow is a self-limiting condition, which resolves within 2-4 weeks. The treatment of herpetic whitlow is aimed at managing the symptoms and recurrence of the disease. Antiviral drugs such as acyclovir are beneficial in such patients. If the patient feels the constant, severe pain, analgesics can also be prescribed.

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3. American Academy of Pediatrics. Herpes simplex. In: Pickering LK, ed. 2003 Red Book: Report of the Committee on Infectious Diseases. 26th ed. Elk Grove Village, IL: American Academy of Pediatrics, 2003:344-353.
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