Warts (Verruca Vulgaris)

Essentials

• All wart treatments are based on stimulating the immune response against papilloma viruses and on the destruction of the visible wart tissue.
• Conservative treatment or waiting for spontaneous recovery gives the best cosmetic results.
• Warts are benign lesions and often disappear with no treatment; scar forming procedures, such as surgery, should therefore be avoided.

Epidemiology and prognosis

• Warts are benign lesions of the skin and mucosa caused by the human papillomavirus (HPV). They are common in all age groups.
• A callus (clavus) often develops around plantar warts, but calluses may also develop as a result of mechanical stress without wart infection.
• The mode of infection and incubation period are not known but are likely to show great variability.
• There is no evidence to suggest that wart infections can be prevented, and interaction with other people should not be restricted.
• Skin warts are not associated with malignant transformation (compare with HPV infection Human Papillomavirus (HPV) Infection).
• In healthy individuals warts usually heal spontaneously, within 2 years in 60% of cases.

Diagnosis

• Diagnosis is clinical.
• The surface of a wart is often rough (verrucous), and small black dots produced by blood vessels are frequently present.
  • Curettage or paring down is needed in some cases to expose the diagnostic blood vessels.
• The dermal ridges on the palms and soles of the feet stop at the wart.
• A biopsy may be taken (for example a punch biopsy) if diagnosis is unclear.
• Location of warts
  • Filiform warts with a stalk occur on the face.
  • On the extremities the warts are flatter, slightly elevated from the skin and their surface is often broken by fissures (pictures 1 2 3 4).
  • In the nail cuticles and on pressure points, particularly on the balls of the feet and heels, warts present as flat plaques or mosaic warts (pictures 5 6 7)).
  • On the soles warts grow deep and may be painful. A callus often develops around a plantar wart (picture 8).
  • Particularly in the young, flat warts that occur in large numbers (verruca plana, picture 9) may be seen at the back of the hand and face.
• The most important differential diagnosis is a callus, which has a smooth surface and often a deep seated painful core (nucleation). In contrast to warts, the dermal ridges on calluses tend to become thicker and more prominent.
  • Very painful plantar lesions suspected to be warts often turn out to be calluses, the treatment of which is based on curettage, reduction of any mechanical friction and the correction of foot posture abnormalities.
  • Calluses can also be softened with keratolytic creams (e.g. salicylic acid preparations, white vaseline etc., usually once daily before bedtime); a hydrocolloid dressing can be used to improve efficacy.

Treatment

• Comprehensive and detailed instructions should be given to the patient and the basis of treatment explained.
• Treatment can be applied to all types of warts (verruca vulgaris, plana etc.)
• Mechanical reduction (paring down)
  • Making a wart regularly thinner by mechanical means (using e.g. sandpaper, pumice stone or a skin curette) is the cornerstone of wart treatment; often the patient may carry this out himself/herself (twice or thrice a week after a wash).
  • The outer thickened layer is removed so that a wart-blood connection is achieved in order to induce an immune response.
  • A keratolytic salicylic acid/lactic acid preparation http://www.dynamed.com/condition/verruca-vulgaris#TOPICAL_TREATMENTS should then be applied to the reduced warts once daily before bedtime. These preparations are available as gels, creams, solutions and patches Local Treatments for Cutaneous Warts. It is important to continue the treatment without interruption for 1-3 months.
• Tretinoinhttp://www.dynamed.com/condition/verruca-vulgaris#TOPICAL_TREATMENTS cream can be used as an alternative to solutions.
• Occlusion therapy
  • Occlusion therapy may be effective in the treatment of warts, but there is no research evidence on it. Occlusion may be accomplished with duct tape, hydrocolloid dressings (e.g. Duoderm^® ) or Compeed^® plasters. The effect is based on irritation, maceration and softening of the wart.
  • A small piece of duct tape, for example, is attached directly on the wart for 4-7 days. Then the tape and devitalized skin are removed and the skin is cleansed with water and soap. A new tape is placed after 12 hours. The cycle may be repeated for a period of 4-6 weeks.
• Cryotherapy (with liquid nitrogen) may be effective in the treatment of warts Cryotherapy for Warts http://www.dynamed.com/condition/verruca-vulgaris#TOPIC_XJS_5G3_Q3B.
  • The warts are frozen from the edge to the centre, including about 2 mm of healthy skin around the wart; freezing time is 3-5 seconds.
  • Usually several sessions are required, for example 3-6 sessions every 1-2 weeks.
  • Over-the-counter cryogenic systems (Wartner^® ) are available. They may be effective against warts in thin skin areas, but their effect is not sufficient for example against plantar warts.
• Ablative laser treatment (e.g. carbon dioxide laser) or other laser therapies (e.g. pulsed dye laser) may be a alternatives for refractory warts http://www.dynamed.com/condition/verruca-vulgaris#TOPIC_TF3_VG3_Q3B.

References

• Tyring S, Conant M, Marini M, Van Der Meijden W, Washenik K. Imiquimod; an international update on therapeutic uses in dermatology. Int J Dermatol 2002 Nov;41(11):810-6. [PubMed]
• Focht DR 3rd, Spicer C, Fairchok MP. The efficacy of duct tape vs cryotherapy in the treatment of verruca vulgaris (the common wart). Arch Pediatr Adolesc Med 2002 Oct;156(10):971-4. [PubMed]
• Ahn CS, Huang WW. Imiquimod in the treatment of cutaneous warts: an evidence-based review. Am J Clin Dermatol 2014;15(5):387-99. [PubMed]
• Loo SK, Tang WY. Warts (non-genital). BMJ Clin Evid 2014;2014():. [PubMed]
• Craw L, Wingert A, Lara-Corrales I. Are salicylic formulations, liquid nitrogen or duct tape more effective than placebo for the treatment of warts in paediatric patients who present to ambulatory clinics? Paediatr Child Health 2014;19(3):126-7. [PubMed]