Infections

Herpetic whitlow

What is herpetic whitlow?

Herpetic whitlow is a painful viralcutaneousinfection that usually affects thedistal fingers or thumbs, and occasionally the toes. It is caused byherpes simplex virus (HSV) type 1 or 2, and can bevesicular orpustular in nature.

Clusteredvesicles, due to HSV, have broken down intoerosions on theproximalnail fold 

Several nail folds are affected by herpetic whitlow in a woman receivingchemotherapy 

Clustered clear vesicles on the proximalnail fold typical of an early phase of a herpetic whitlow 

A herpetic whitlow on the thumb five days after onset 

Clustered clear vesicles andoedema in an early herpetic whitlow in skin of colour (HW-patient1)

Early clustered vesicles in a herpetic whitlow 

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Who gets herpetic whitlow?

One case series reported theincidence of herpetic whitlow as 2.4 cases per 100,000 people per year. Males and females appear to be equally affected.

In young children, herpetic whitlow commonly occurs followingoral herpes infection. This is thought to be related to thumb sucking causingautoinoculation from active herpeticlesions in the mouth.

Herpetic whitlow in adults is more commonly associated with exposure togenital herpes, or occupational exposure of dental and other health care workers to patients with herpessimplex including oral secretions.

People who areimmunosuppressed are also moresusceptible to herpeticinfections.

What causes herpetic whitlow?

• Autoinoculation through spread from other herpetic lesions such as oral orgenital herpes.
• Directexogenousinoculation from an external source.
• Viral reactivation following previousherpes simplex virus (HSV) type 1 or 2. HSV results in viral invasion and replication inepidermal anddermal cells, which canprogress to involve the sensorydorsal rootganglion. Here, HSV remains and can be periodically reactivated to cause disease anywhere (including the fingertips).
• Patients may report precedingtrauma such as a torncuticle.

What are the clinical features of herpetic whitlow?

• Patients typically present with a painful swollendigit, often the thumb or index finger.
• Possibleprodromalfever andmalaise.
• Localised itch, burning, and altered sensation (may precedevesicle formation).
• One or more (often clustered) 1–3 mm fluid-filled vesicles with surroundingerythema, most often affecting the distalphalanx.
• Vesicular fluid is usually clear but can progress to become turbid, sero-purulent, orhaemorrhagic.
• Vesicles cancoalesce into largerbullae and can spread proximally.
• Proximallymphangitis andlymphadenopathy may be observed.
• Typically, the vesicles willcrust and desquamate over several weeks and resolve without any treatment.
• Other herpetic lesions (eg, oral orgenital) may also be present.
• The thumb or index finger are most commonly affected; it is unusual for more than one digit to be affected.

View images of herpetic whitlow

What are the complications of herpetic whitlow?

• Superimposedbacterial or fungal infection and potentialabscessdevelopment.
• Secondaryherpes simplex infection including spread to oral,ocular, orgenital areas.
• Recurrence (~23% in onepaediatric review).

How is herpetic whitlow diagnosed?

Herpetic whitlow can be diagnosed clinically based on history and appearance of the lesions.

Viral cultures or aTzanck smear can be used to confirm the diagnosis. Ballooningmultinucleatedgiant cells andeosinophilicinclusion bodies are seen on the Tzanck smear. Abacterial swab can also be taken if secondary orconcurrent bacterial infection is suspected.

What is the differential diagnosis for herpetic whitlow?

• Otherparonychia (eg, staphylococcal infection).
• Cellulitis.
• Digital pulp abscess (felon).
• Early localisedhand, foot, and mouth disease (HFMD) can present similarly with vesicular orpapulovesiculareruption.

What is the treatment for herpetic whitlow?

General measures

• Education on skin protection — keep affected digit/s clean and covered with a dressing to prevent further irritation and spread, as viral shedding can occur until all lesions have cleared.
• Topicalantiseptics can be used.
• Simpleanalgesia as required for pain.

Specific measures

• Antivirals (eg, topical or oralaciclovir, or valaciclovir) commenced within 48 hours ofsymptom onset may reduce the duration of symptoms and risk of recurrence.
• Consider suppressive orprophylacticantiviral therapy for those withrecurrent flares or severe episodes, especially if they are immunosuppressed.
• For superimposed bacterial infection,antibiotics may be indicated.
• Surgical drainage is not recommended due to the risk of viraemia and secondary bacterial infection.
• Consider testing forHIV if thelesion is extensive and if there are risk factors.

How can herpetic whitlow be prevented?

• Those at higher occupational risk are advised to use gloves when in contact with patients with symptoms ofherpes simplex.
• Children with oral herpes should be discouraged from sucking their thumb.

What is the outcome for herpetic whitlow?

Herpetic whitlow isself-limiting and usually resolves without any complications in 2–4 weeks. Recurrence is possible due to reactivation of the virus, which can be triggered by stress, other illness, or trauma to the skin ornails. Recurrent episodes are usually less severe than theprimary infection.

View images of herpetic whitlow

References

• Betz D, Fane K. Herpetic Whitlow. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022.Available here
• Gill MJ, Arlette J, Buchan K. Herpes simplex virus infection of the hand: A profile of 79 cases. Am J Med. 1988;84(1):89–93. doi: 10.1016/0002-9343(88)90013-7.Journal
• Klotz RW. Herpetic whitlow: an occupational hazard. AANA J. 1990;58(1):8–13.Journal
• Lieberman L, Castro D, Bhatt A, Guyer F. Case report: palmar herpetic whitlow and forearm lymphangitis in a 10-year-old female. BMC Pediatr. 2019;19(1):450. doi: 10.1186/s12887-019-1828-5.Journal
• Robayna MG, Herranz P, Rubio FA, et al. Destructive herpetic whitlow in AIDS: report of three cases. Br J Dermatol. 1997 Nov;137(5):812–5.Journal
• Szinnai G, Schaad UB, Heininger U. Multiple herpetic whitlow lesions in a 4-year-old girl: case report and review of the literature. Eur J Pediatr. 2001 Sep;160(9):528–33. doi: 10.1007/s004310100800.Journal

On DermNet

• Herpetic whitlow images
• Herpes simplex
• Herpes viruses
• Viral infections and the skin
• Blistering skin conditions
• Paronychia
• Tzanck smear
• Aciclovir

Books about skin diseases

• Books about the skin
• Dermatology Made Easy - second edition