Activated by HSV thymidine kinase (viral-specific enzyme)
Inhibit viral DNA polymerase, preventing replication
Selective for HSV-infected cells; minimal toxicity to normal cells
Valacyclovir: prodrug of acyclovir
Better oral bioavailability than acyclovir (55% vs 15-30%)
Fewer daily doses required
Famciclovir: prodrug of penciclovir
Bioavailability 77%
Long intracellular half-life allows twice or three times daily dosing
Treatment timing evidence base
Greatest benefit when initiated during prodrome or within 48-72 hours of lesion onset
Reduces duration of viral shedding
May reduce lesion duration by 1-2 days
Beyond 72 hours: antivirals have diminishing impact on episode duration
Still reasonable to initiate given safety profile and suppression of shedding
Acyclovir resistance
Occurs in approximately 3-5% of immunocompromised patients on chronic acyclovir
Mechanism: loss or mutation of viral thymidine kinase
Resistance rare in immunocompetent hosts
Clinical features: failure to heal on standard acyclovir after 7-10 days
Foscarnet is treatment of choice: acts independently of thymidine kinase
Hydration and renal protection
Acyclovir can precipitate in renal tubules causing crystalline nephropathy
Risk highest with IV formulation, dehydration, and pre-existing renal impairment
Oral acyclovir: encourage minimum 2 L of fluid daily
IV acyclovir: administer over 1 hour with concurrent hydration
Patient Discharge Instructions
copy discharge instructions
Diagnosis and what to expect
Your finger is infected with herpes simplex virus (herpetic whitlow)
This is a viral infection that causes painful blisters on the finger
The infection will heal on its own in 2-3 weeks in most people
Antiviral medication may help shorten the duration if started early
Do NOT squeeze, pop, or cut open the blisters
Opening the blisters increases the risk of bacterial infection
This is the most common cause of complications from this condition
Medications
Take your antiviral medication exactly as prescribed
Complete the full course even if the blisters start to heal
Take with plenty of water (at least 8 glasses per day)
For pain, you may use
Acetaminophen (Tylenol) 325-500 mg every 4-6 hours as needed
Ibuprofen (Advil, Motrin) 400-600 mg every 6-8 hours with food as needed
Do not use antibiotics unless specifically prescribed for you
Wound care
Keep the finger clean and dry
Cover with a clean, non-adhesive bandage
Change the dressing once or twice daily or when wet
Elevate your hand above heart level to reduce swelling
Contagion and infection control
The virus is contagious until all blisters are fully crusted over
This typically takes 7-10 days
Avoid direct skin contact between your affected finger and other people
Especially avoid contact with newborns and immunocompromised individuals
Avoid touching your eyes with the affected finger (risk of eye infection)
Wash hands frequently with soap and water
Healthcare workers: do not perform direct patient care until fully healed
Return to Emergency Department immediately if
The redness spreads up your hand or arm
Red streaks develop along the forearm
You develop fever above 38.5 C (101.3 F)
The pain becomes much worse or swelling increases rapidly
You develop a tense, firm lump in the finger (possible bacterial abscess)
Your finger becomes difficult to straighten or bend (possible tendon infection)
You are immunocompromised and the infection is not improving
Follow-up
Follow up with your primary care physician or urgent care in 7-10 days
Return sooner if symptoms are worsening
If you have frequent recurrences (6 or more per year), discuss preventive antiviral medication with your doctor
At the first sign of tingling or burning at the site in the future, start antiviral medication if prescribed
References
Guidelines and key sources
IDSA Practice Guidelines for Skin and Soft Tissue Infections 2014
Stevens DL, Bisno AL, Chambers HF, et al.
Clinical Infectious Diseases 2014
doi: 10.1093/cid/ciu296
Defines herpetic whitlow as an aseptic process; I&D contraindicated
IDSA/ASM Guide to Utilization of Microbiology Laboratory 2024
Miller JM, Binnicker MJ, Campbell S, et al.
Clinical Infectious Diseases 2024
doi: 10.1093/cid/ciae104
PCR preferred over viral culture for HSV skin and mucosal infections
IDSA Opportunistic Infections in HIV Guidelines 2025
Benson C, Brooks J, Dhanireddy S, et al.
IDSA and Office of AIDS Research Advisory Council 2025
Foscarnet recommended for acyclovir-resistant HSV in immunocompromised patients
Primary literature
Gill MJ, Arlette J, Tyrrell DL, Buchan KA (1988)
Herpes Simplex Virus Infection of the Hand: Clinical Features and Management
American Journal of Medicine 1988
PMID: 3407676
Documents antiviral dosing and efficacy for HSV hand infections
Salerno N, Doolan JJ (2022)
An Unusual Pediatric Manifestation of the Herpes Simplex Virus
Journal of the American Podiatric Medical Association 2022
PMID: 35994408
Describes pediatric presentation, misdiagnosis rates, and recurrence data
Szinnai G, Schaad UB, Heininger U (2001)
Multiple Herpetic Whitlow Lesions in a 4-Year-Old Girl: Case Report and Review
European Journal of Pediatrics 2001
PMID: 11585074
Reviews antiviral use in pediatric whitlow
Polayes IM, Arons MS (1980)
The Treatment of Herpetic Whitlow: A New Surgical Concept
Plastic and Reconstructive Surgery 1980
PMID: 6247731
Landmark article establishing conservative management over I&D
Additional references
Rerucha CM, Ewing JT, Oppenlander KE, Cowan WC (2019)
Acute Hand Infections
American Family Physician 2019
PMID: 30763047
Comprehensive review including herpetic whitlow differential diagnosis
Gottlieb M, Long B (2025)
Management of Finger Felons and Paronychia: A Narrative Review
Journal of Emergency Medicine 2025
PMID: 40945390
Emergency medicine perspective on distinguishing whitlow from bacterial felon
Clark DC (2003)
Common Acute Hand Infections
American Family Physician 2003
PMID: 14677662
General review with whitlow differential and management
Whitley RJ, Roizman B (2001)
Herpes Simplex Virus Infections
Lancet 2001
PMID: 11377626
Foundational review of HSV biology, epidemiology, and treatment
Tuddenham S, Hamill MM, Ghanem KG (2022)
Diagnosis and Treatment of Sexually Transmitted Infections: A Review
JAMA 2022
doi: 10.1001/jama.2021.23487
HSV treatment evidence including suppressive therapy thresholds
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.