Basics
Description
- Warts (verrucae) are common, benign, and frequently self-limited epithelial growths caused by human papillomavirus (HPV) infection of keratinocytes.
- Types of warts
- Cutaneous
- Common warts (verruca vulgaris)
- Flat warts (verruca plana)
- Plantar warts (weight-bearing)
- Anogenital
- Laryngeal (laryngeal papillomatosis)
Epidemiology
Prevalence
- Cutaneous warts
- Mostly affect children and young adults
- Affect girls more than boys
- 5.3% prevalence from age 6 to 15 years of age
- Up to 1/3 of school-aged children have had warts.
- Anogenital warts
- Exact prevalence in children and adolescents is unknown.
- Approximately 1% of sexually active adults have external genital warts.
- Laryngeal warts
- Rare with no known cure; transmission occurs in utero or through birth canal
Risk Factors
- Direct or indirect contact
- Autoinoculation can cause persistent infection and spread.
- Use of communal pool surfaces, bathrooms, and shower rooms increases risk.
- Areas of skin trauma and breakdown have increased susceptibility to HPV infection.
- Regularly walking barefoot outside also increases risk.
- Excessive foot perspiration
- Immunosuppressed patients, particularly transplant patients, are highly vulnerable.
- Individual susceptibility factors related to developing warts after exposure to HPV are less clear.
General Prevention
- Cutaneous warts
- Use protective footwear in warm, moist environments and communal areas.
- Wear cotton socks and change twice a day, especially if significant perspiration.
- Avoid sharing nail files.
- Avoid scratching and nail-biting to prevent autoinoculation.
- Anogenital warts
- Avoid sexual contact with multiple partners.
- Condoms may be protective.
- Quadrivalent HPV vaccine protects against HPV subtypes 6, 11, 16, and 18.
- Recommended universally for males and females, ages 9 " 26 years
Pathophysiology
- Warts are caused by HPV infection of the epithelium.
- HPV replication leads to cell proliferation and formation of characteristic lesions.
Etiology
- Over 150 subtypes of HPV exist.
- Certain subtypes have a predilection for particular body sites and produce characteristic lesions:
- Plantar and common palmar warts often caused by HPV 1 and 2
- Anogenital warts commonly caused by HPV 6, 11, 16, 18, 31, and 45
- Laryngeal papillomatosis is associated with HPV 6 and 11.
Diagnosis
History
- Ask about risk factors for warts.
- Assess history of warts in close contacts (caregiver).
- Assess for immunosuppression.
- For anogenital warts: Take detailed sexual history and assess risk for sexual abuse.
- Assess symptoms: Warts are usually asymptomatic with the exception of plantar warts or warts near nails, which may be painful.
- Assess duration: Warts may be present for months to years without intervention.
Physical Exam
- Common warts (verruca vulgaris)
- Rough keratotic papules and nodules that can be single or grouped
- Often dome-shaped
- Appear anywhere but most often affect fingers, hands, knees, and elbows
- Flat warts (verruca plana)
- Generally 2 " 4 mm, slightly elevated, flat-topped lesions with minimal scale
- Plantar warts (weight-bearing warts)
- Thick, hyperkeratotic lesions that may be tender to palpation
- Tend to occur at pressure points on soles of feet
- May have punctate black dots representing thrombosed capillaries
- Disrupt normal skin markings
- Anogenital warts
- Usually multiple, clustered soft lesions that are pink or gray
- 4 morphologic types: condyloma acuminata (cauliflower-shaped), smooth papules (dome-shaped, flesh-colored), keratotic papules (resemble common warts), flat warts
- Laryngeal warts (laryngeal papillomatosis)
- Visible only under direct airway examination
- Children may present with stridor, hoarseness, and signs of airway obstruction.
- In children, laryngeal warts are diagnosed most often between 2 and 3 years, with most children presenting before age 5 years.
Diagnostic Tests & Interpretation
- Diagnosis is based on visual identification.
- Biopsy may be indicated when the diagnosis is uncertain or warts are resistant to treatment.
- In anogenital warts, testing for other sexually transmitted infections is recommended.
Differential Diagnosis
- Common warts
- Molluscum contagiosum
- Moles
- Skin tag
- Squamous cell carcinoma or melanoma
- Flat warts
- Lichen planus
- Lichenoid keratosis
- Plantar warts
- Callus
- Corns
- Squamous cell carcinoma or melanoma
- Foreign body
- Anogenital warts
- Pearly penile papules
- Molluscum contagiosum
- Condylomata lata (secondary syphilis lesions)
- Vulvar carcinoma
- Lichen planus
- Squamous cell carcinoma
Alert
- Any child or adolescent with anogenital warts should prompt consideration for sexual abuse and consultation with a child abuse specialist as necessary.
- Testing for other sexually transmitted infections should occur in any pediatric patient with anogenital warts.
- In any patient with extensive HPV infection, consideration must be given to underlying immunodeficiencies including HIV.
Treatment
- General
- Warts are often self-limited and resolve without treatment.
- 2/3 of warts will resolve within 2 years with no treatment.
- Earlier treatment may be warranted for warts that are painful or cause significant social stigma.
- Cutaneous warts
- Salicylic acid
- 1st-line therapy for cutaneous warts
- Over-the-counter (OTC) formulations contain 5 " 27% salicylic acid and are applied topically 1 " 2 daily for up to 12 weeks.
- Prescription strength 40% adhesive plaster is available to be applied for 24 " 48 hours and are particularly useful for plantar warts.
- Repetitive filing of the wart with either an emery board, pumice stone, or metal file and soaking the wart for 10 " 20 minutes prior to treatment may improve response to topical salicylic acid.
- Applying a thin layer of petrolatum around the wart to protect the surrounding healthy tissue may prevent pain during treatment.
- Duct tape or moleskin
- Used as 1st-line therapy
- May be helpful, although studies on effectiveness are mixed
- To use, cut tape or moleskin approximately ¼ inch larger than wart and cover for 6 days.
- After 6 days, remove, soak wart, and file with an emery board, pumice stone, or metal file; leave uncovered overnight.
- Reapply duct tape in 6 day cycles until resolution.
- Cryotherapy
- 2nd-line therapy
- Involves freezing the wart using one of several methods, the most commonly used being liquid nitrogen
- Can be painful and is more expensive than 1st-line agents
- Fewer data support its efficacy as compared to salicylic acid.
- Most commonly used in the office although newer OTC cryotherapy products are available.
- 3rd-line therapies are generally performed in conjunction with a pediatric dermatologist.
- Phototherapy
- Immunotherapies
- Intralesional therapies
- Antimitotic therapies
- Curettage
- Laser ablation
- Anogenital warts
- Treatment issues
- Main goal of treatment is to remove symptomatic warts.
- Most warts will clear within 3 months after initiation of therapy.
- Treatment does not eradicate HPV, prevent recurrence, or reduce cancer risk.
- Podofilox (0.5% gel) or imiquimod (5% cream) are 1st-line therapy (avoid in pregnancy).
- Podofilox gel is applied topically q12h for 3 days; no treatment for 4 days; then repeat cycles until warts disappear; avoid unprotected sexual activity during treatment due to possible irritant effect.
- Imiquimod: for patients aged 12 years and older; apply 3 /week at bedtime; wash off 6 " 10 hours later; treat until resolution
- Cryotherapy for anogenital warts is an option for experienced providers.
- 2nd-line options include podophyllin resin, intralesion treatments, trichloroacetic acid, surgical removal, laser therapy, and photodynamic therapy.
Ongoing Care
Follow-up Recommendations
Patient Monitoring
Patients should be seen at regular intervals to assess clearance of the lesions and monitor for side effects.
Issues For Referral
Consider referral to pediatric dermatology if
- Lesions are atypical or extensive.
- Lesions progress during therapy.
- Multiple failed treatment occurs.
- Lesions are located on the face.
- Frequent or prompt recurrence occurs.
- Warts are pigmented, indurated, ulcerated, or fixed to underlying structures.
- Individual warts are greater than 1 cm.
- Patients are immunocompromised.
Consider referral to a child abuse specialist if anogenital warts are present AND
- Caregivers suspect sexual abuse.
- A sexual predator has access to the child.
- Child discloses abuse.
- Child is older than 48 months of age.
- Any other sexually transmitted infection is detected.
- Physical exam suggests any type of abuse.
- Provider is uncomfortable with evaluating for sexual abuse.
Prognosis
- 2/3 of warts clear without treatment within 2 years.
- However, early treatment is recommended while warts are small and few in number to prevent enlargement and spread.
Complications
- Bacterial infection such as cellulitis or abscess can occur if patients pick at warts.
- Other complications are generally related to treatment and can include pain and scarring.
- Malignant transformation to squamous cell carcinoma can rarely occur for both cutaneous and anogenital warts; this is most problematic in immunosuppressed patients.
Additional Reading
- Boull C, Groth D. Update: treatment of cutaneous viral warts in children. Pediatr Dermatol. 2011;28(3):217 " 229. [View Abstract]
- Kwok C, Holland R, Gibbs S. Efficacy of topical treatments for cutaneous warts: a meta-analysis and pooled analysis of randomized controlled trials. Brit J Dermatol. 2011;165(2):233 " 246. [View Abstract]
- Kwok CS, Gibbs S, Bennett C, et al. Topical treatments for cutaneous warts. Cochrane Database Syst Rev. 2012;9:CD001781. [View Abstract]
- Mulhem E, Pinelis S. Treatment of nongenital cutaneous warts. Am Fam Physician. 2011;84(3):288 " 293. [View Abstract]
- Sinclair K, Woods C, Sinal S. Veneral warts in children. Pediatr Rev. 2011;32(3):115 " 121. [View Abstract]
Codes
ICD09
- 078.10 Viral warts, unspecified
- 078.12 Plantar wart
- 078.11 Condyloma acuminatum
- 078.19 Other specified viral warts
ICD10
- B07.9 Viral wart, unspecified
- B07.0 Plantar wart
- A63.0 Anogenital (venereal) warts
- B07.8 Other viral warts
SNOMED
- 57019003 Verruca vulgaris (disorder)
- 63440008 Verruca plantaris (disorder)
- 240542006 Anogenital warts (disorder)
- 402908003 oral wart (disorder)
- 266113007 Genital warts (disorder)
- 240539000 Plane wart (disorder)
- 19138001 epidermodysplasia verruciformis (disorder)
FAQ
- Q: Do condoms protect against HPV?
- A: Condoms lower the risk of HPV; however, HPV can infect areas not covered by the condom and so condoms are not fully protective.
- Q: Does a patient with cutaneous warts need to be excluded from school or sports?
- A: No. Exclusion is not fully effective because asymptomatic transmission can occur. In addition, risk of transmission is low.
- Q: How can a callous and wart be differentiated?
- A: Careful paring with a #15 scalpel of a callous shows preserved skin markings and no bleeding. Paring of a wart often reveals black dots, which are thrombosed blood vessels.