Viral Skin Infections Common and Flat Warts

Viral Skin Infections: Common and Flat Warts

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Viral Skin Infections: Common and Flat Warts Penny F. Miller, BSc(Pharm), MA Date of Revision: September 2014

Pathophysiology

Warts are common viral infections of the skin and mucus membranes caused by any of 100 or more distinct deoxyribonucleic acid (DNA) viruses in the human papillomavirus (HPV) family. Since warts resemble small hills on the skin, they are named “verruca” which means “a steep place.” Children and young adults are most commonly affected. Handlers of meat, poultry and fish have a high incidence of warts. It has been estimated that about 12% of the population have a wart at any given time with the highest prevalence (up to 20%) in school-aged children.1 Warts are usually spread through broken skin by direct skin-to-skin inoculation of the virus from an infected person. Skin maceration appears to promote viral infections as there are increased incidences associated with swimmers in public pools.2 The degree of exposure to HPV at home and in school contributes to wart development in elementary school children.3 Time between inoculation and the appearance of a lesion is variable, ranging from 2–9 months for common warts. Cell-mediated immune responses to the virus are important in host resistance.4 Immunosuppressed states and renal transplants predispose one for more extensive or recalcitrant warts.2 Based on their location, there are several different forms of self-treatable warts including common warts (hands), flat warts (face) and plantar warts (foot).4 See Plantar Warts.

Common Warts

Common warts are caused by HPV types 2, 4, 27 and 29. They appear as single or grouped, hyperkeratotic papulonodules most often seen on the knees, fingers, hands and around the nails. They can occur anywhere on the skin. The lesions typically are small, hard, raised growths with a rough surface that looks like cauliflower. Spontaneous remission occurs in about two-thirds of affected patients within 2 years. Recurrence is common.5 (See photo, Common Warts.) Photo 1: Common Warts

Dr. P. Marazzi/Science Photo Library

Flat Warts

Flat warts are caused by HPV types 3, 10, 28 and 49 and frequently present as several flesh-coloured, small papules with a smooth surface affecting the face or neck. The skin and dorsa of hands may also be involved. They

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may arise after scratching or some traumatic event and appear in a linear arrangement.4

Goals of Therapy

Remove the virus-containing wart with minimal destruction of normal tissue Prevent spread of the wart

Patient Assessment

A description and differential diagnosis of warts can be found in Table 1. Nongenital warts may cause pain and bleed if irritated; otherwise they produce no symptoms and are harmless. Table 1: Characteristics and Differential Diagnosis of Common and Flat Warts

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Condition

Distribution

Lesion

Differential Diagnosis

Common warts

Hands, surrounding or beneath the nails, or sites of trauma

Flesh-toned or grey-brown papule, studded with black dots occurring singly or in groups

Callus: has skin lines.

Seborrheic keratosis: greasy, pigmented (dirty yellow to black colour) appearance, affects middle-aged and elderly persons.

Molluscum contagiosum: a small, fleshcoloured, firm, domed papule with a central pore indentation. A cheesy white material can be expressed. It affects primarily children and sexually active young adults.

Comedone (whitehead): contents can be expressed. Occurs in the presence of other acne lesions, e.g., pustules (pimples). Skin tags: flesh-coloured papules that lack the roughness of warts.

Squamous cell carcinoma: an asymptomatic skin-coloured to reddish-brown firm tumor on damaged skin. Usually there is a central ulceration. It occurs in sun-exposed areas and appears later in life. Flat warts

Face; backs of hands; shins

Flat warts: skin-coloured or light brown, smooth, flat or slightly elevated papules occurring in multiples

Epidermal nevi (linear birth marks present since birth).

Patients presenting with warts on the face or genitals should be referred to a physician, as should patients with flat warts and those with resistant or widespread lesions. Patients with neuropathies such as diabetes or circulatory disorders should not self-medicate with caustic substances because they are unable to judge the extent of the therapy and are more likely to have poor healing.5,6

Nonpharmacologic Therapy

Based on the natural course of warts, one-half of primary school children with warts will have resolution one year later.

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The resolution rates are higher in young children and those with non-Caucasian skin types, independent of the number and/or size of warts. Given this information, consider discussion of a wait and see approach with the patient and/or family.9 Patients should avoid scratching or biting the wart. This will prevent the development of pain or bleeding and will reduce the spread of the virus. Patients should not share personal items such as towels that have been in contact with the wart. Watchful waiting in children is appropriate since two-thirds of untreated warts will disappear within 2 years.5 However, warts can enlarge and multiply if untreated.6 A small number of trials have examined the use of duct tape to impede viral survival by creating an occlusive environment. In one study using silver-coloured duct tape applied in cycles of 6 days on, 1 night off, with soaking and debriding of the wart, an 85% resolution rate was reported.10 Other more rigorous trials using clear duct tape with acrylic-based adhesive rather than rubber-based adhesive found no benefit.11,12 Since there is no clear evidence of effectiveness and adverse effects such as redness, itching, eczema and bleeding have been reported,11 duct tape is not recommended.13

Pharmacologic Therapy

Topical therapy is used to remove the virus-containing wart with minimal destruction of normal tissue. The type of therapy depends on the location, degree of symptoms and the patient's immune status and level of cooperation. Scarring can occur with more destructive therapies. Therapy may take several weeks or months. Evidence is insufficient to support the use of therapies other than salicylic acid or cryotherapy for the local treatment of common warts.14,15,16 Common warts can be self-treated topically with salicylic acid, which has produced a cure rate of 52% compared to 23% with placebo.16 Salicylic acid is an effective keratolytic that causes a slow destruction of the virus-infected epidermis. In addition, an immune response is stimulated by the resulting mild irritation of the epidermis.2 Salicylic acid is commercially available in a variety of strengths and dosage forms that may be combined with lactic acid. Generally, strengths of about 17% in liquid (collodion) form are useful for common warts and multiple warts, whereas strengths of 20–40% as plasters are preferred for thicker skin areas such as plantar warts (Table 2).1 Instructions for use can be found in the Patient Information section. A dimethyl-ether/propane mixture is available for cryotherapy but does not appear to be effective in achieving the low temperatures necessary for cellular necrosis.2,18 Table 2: Nonprescription Wart Treatment

For product selection, consult Compendium of Products for Minor Ailments. Foot Care Products: Corns, Calluses and Warts.

Class

Drug

Uses

Keratolytic

salicylic acid

Common warts

liquid/ patches

Flat warts

Useful in Young Children Yes

Cure Rate 52%16

Pain with Application No

Comments Best supportive evidence for efficacy.14,17 Use 40% for thick areas and 17% for thin warts.5 Lactic acid 17% combination is effective.5

Assess response after 2–3 wk.5 Apply for up to several months.

Continue treatment for 1–2 wk after clinical removal of

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For product selection, consult Compendium of Products for Minor Ailments. Foot Care Products: Corns, Calluses and Warts.

Class

Drug

Uses

Useful in Young Children

Cure Rate

Pain with Application

Comments wart to ensure complete elimination of virus. Stop treatment for a few days if treated area becomes painful and excessively irritated.

Prescription Therapy

Physician-administered cryotherapy with liquid nitrogen every 2 weeks can produce a cure rate of 49% after 13 weeks.19 Melamine foam sponge applicators rather than cotton swab applicators may be the optimal method of application of liquid nitrogen in this setting.20 Freezing temperatures to −196°C cause cell necrosis and may induce local inflammation where an effective cell-mediated response clears the virus. Cryotherapy has comparable efficacy to topical salicylic acid but causes more adverse effects including pain, blistering, scarring, skin irritation, skin pigmentation and crusting.13,14 Cryotherapy is more suitable as a second-line treatment in adults who can tolerate the application discomfort.13 Other physician-directed topical treatments with limited evidence for benefit include bichloracetic acid, cantharidin, imiquimod, 5-fluorouracil, tretinoin, glutaraldehyde or formaldehyde.2,4,14,21 Resistant warts often require cryotherapy every 10–14 days combined with salicylic acid or curettage and electrodessication.2 In extensive recalcitrant warts, a variety of other physician-directed systemic treatment modalities have been used with limited evidence of benefits and risks. Oral cimetidine 30–50 mg/kg/day (usually 4 times daily) for up to 3 months may have immunomodulatory activity and some open trials have suggested benefit.22,23 A controlled trial showed no advantage over placebo.24 An oral retinoid, acitretin 1 mg/kg/day for 3 months, has fair evidence of efficacy in children with extensive warts.25 Dermatologists may offer immunotherapy (induction of an allergic reaction with dinitrochlorobenzene), intralesional bleomycin, intralesional interferons or photodynamic therapy and pulsed dye laser.2,4

Monitoring of Therapy

Table 3 presents a monitoring framework for patients with warts. Table 3: Monitoring Therapy for Warts Symptoms

Monitoring

Desired Outcome

Actions

Wart size

Patient: daily, watching for dead skin and reduction in the size of the wart

Reduction in the size of the wart within 2–3 wk Disappearance of the wart within 4 or more wk. Return of normal healthy skin

Pharmacist should review application technique and evaluate dosage form if no improvement in 2–3 wk.

(treatment with salicylic acid)

Pharmacist: review response in 2–3 wk

Refer patient to a physician if there is no

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Symptoms

Monitoring

https://www.e-therapeutics.ca/print/new/documents/MA_CHAPTER/en/... Desired Outcome

Actions improvement in the wart after 12 wk of treatment.

Wart colour or shape suggesting it may not be a wart

Patient: daily, watching for any unexpected dramatic change in colour or shape

Disappearance of the wart/lesion

Refer patient to a physician if there is any unusual change in colour or shape of the lesion. Need to rule out cancers.

Bleeding after minimal trauma

Patient: daily

Absence of bleeding

Refer patient to a physician if there is any unexplained bleeding. Need to rule out cancers.

Signs of infection such as redness, pain and pus

Patient: daily

Absence of infection

Refer patient to a physician if signs are suggestive of a secondarily infected lesion.

Warts that are growing quickly

Patient: daily

Absence of enlarging or new warts

Refer patient to a physician.

Allergy

Patient: daily while on therapy

No allergy

Stop therapy. Refer patient to a physician.

Little to no irritation that subsides with continued use

Stop therapy if no improvement after reinforcing method of application. Refer patient to a physician.

Pharmacist: next visit

Pharmacist: next visit

Pharmacist: next visit

Pharmacist/Physician: next visit

Irritation caused by topical agents

Patient: daily while on therapy Pharmacist/Physician: next visit

Suggested Readings

Bacelieri R, Johnson SM. Cutaneous warts: an evidence-based approach to therapy. Am Fam Physician 2005;72:647-52. Goldstein BG, Goldstein AO. Cutaneous warts. Available from: www.uptodate.com. Subscription required.

References 1. Schenefelt PD. Warts, nongenital. Available from: emedicine.medscape.com. Accessed May 5, 2009. Registration required. 2. Sterling JC, Handfield-Jones S, Hudson PM. Guidelines for the management of cutaneous warts. Br J Dermatol 2001;144:4-11. 3. Bruggink SC, Eekhof JA, Egberts PF et al. Warts transmitted in families and schools: a prospective cohort. Pediatrics 2013;131:928-34. 4. Androphy EJ, Lowy DR. Warts. In: Goldsmith LA et al. Fitzpatrick's dermatology in general medicine. 8th ed.

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New York: McGraw-Hill Professional; 2012. 5. Goldstein BG, Goldstein AO. Cutaneous warts. Available from: www.uptodate.com. Subscription required. 6. Goldstein BG, Goldstein AO. Practical dermatology. 2nd ed. St. Louis: Mosby; 1997. p. 71-7. 7. Hooper BJ, Goldman MP. Primary dermatologic care. St. Louis: Mosby; 1999. 8. Lookingbill DP, Marks JG. Principles of dermatology. 3rd ed. Philadelphia: W.B. Saunders; 2000. 9. Bruggink SC, Eekhof JA, Egberts PF et al. Natural course of cutaneous warts among primary school children: a prospective cohort study. Ann Fam Med 2013;11:437-41. 10. Focht DR, 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;156:971-4. 11. de Haen M, Spigt MG, van Uden CJ et al. Efficacy of duct tape vs placebo in the treatment of verruca vulgaris (warts) in primary school children. Arch Pediatr Adolesc Med 2006;160:1121-5. 12. Wenner R, Askari SK, Cham PM et al. Duct tape for the treatment of common warts in adults: a double-blind randomized controlled trial. Arch Dermatol 2007;143:309-13. 13. Craw L, Wingert A, Lara-Corrales I. Are salicylic acid formulations, liquid nitrogen or duct tape more effective than placebo for the treatment of warts in paediatric patients who present to ambulatory care clinics? Paediatr Child Health 2014;19:126-7. 14. Kwok CS, Gibbs S, Bennett C et al. Topical treatments for cutaneous warts. Cochrane Database Syst Rev 2012;9:CD001781. 15. Dall'oglio F, D'Amico V, Nasca MR et al. Treatment of cutaneous warts: an evidence-based review. Am J Clin Dermatol 2012;13:73-96. 16. Kwok CS, Holland R, Gibbs S. Efficacy of topical treatments for cutaneous warts: a meta-analysis and pooled analysis of randomized controlled trials. Br J Dermatol 2011;165:233-46. 17. Bacelieri R, Johnson SM. Cutaneous warts: an evidence-based approach to therapy. Am Fam Physician 2005;72:647-52. 18. Gaspar ZS, Dawber RP. An organic refrigerant for cryosurgery: fact or fiction? Australas J Dermatol 1997;38:71-2. 19. Bruggink SC, Gussekloo J, Berger MY et al. Cryotherapy with liquid nitrogen versus topical salicylic acid application for cutaneous warts in primary care: randomized controlled trial. CMAJ 2010;182:1624-30. 20. Canadian Agency for Drugs and Technologies in Health. Cryotherapy systems for wart removal: a review of the clinical effectiveness, cost-effectiveness, and guidelines. Available from: www.cadth.ca/en/products/rapidresponse/publication/4286. Accessed September 11, 2014. 21. Lio P. Warts, molluscum and things that go bump on the skin: a practical guide. Arch Dis Child Educ Pract Ed 2007;92:ep119-24. 22. Orlow SJ, Paller A. Cimetidine therapy for multiple viral warts in children. J Am Acad Dermatol 1993;28:794-6. 23. Glass AT, Solomon BA. Cimetidine therapy for recalcitrant warts in adults. Arch Dermatol 1996;132:680-2. 24. Yilmaz E, Alpsoy E, Basaran E. Cimetidine therapy for warts: a placebo-controlled, double-blind study. J Am Acad Dermatol 1996;34:1005-7. 25. Gelmetti C, Cerri D, Schiuma AA et al. Treatment of extensive warts with etretinate: a clinical trial in 20 children. Pediatr Dermatol 1987;4:254-8.

Warts — What You Need to Know What are warts?

Warts are small, round, hard bumps on the skin that have a rough surface (like a cauliflower). They may be white, pink or brown and they may have little black dots inside.

Warts are most often found on fingers, hands and the bottom of the feet. They can grow on any part of the body. Warts usually do not cause pain except when they are on the bottom of the feet.

What causes warts?

Warts are caused by a virus called the Human papilloma virus. This virus can be spread from person to person

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by touching the wart. Some people get warts easily while others never do. It is not known why this happens.

How are warts treated?

Most warts go away without any treatment but it can take a long time for a wart to disappear. Using a wart treatment is a good idea if: the wart is painful

it bleeds if it is bumped or rubbed by clothing it makes you feel embarrassed

you want to prevent warts from spreading to other areas of the body or to other people

Wart treatments kill the skin that contains the virus. Ask your pharmacist for advice about the best wart treatment for you.

Tips for Using a Wart Treatment

Follow these steps for treating warts:

Soak the wart in warm water for about 10 minutes. Then dry the skin lightly. Apply petroleum jelly (Vaseline) to protect the normal skin around the wart.

Carefully apply a wart treatment solution (salicylic acid) directly to the wart. You may need to use a toothpick to apply some solutions. Let the liquid dry for 5 minutes. Cover the wart with adhesive tape. This keeps the skin moist so the medicine can get into the wart and work better. After 24 hours, remove the tape. The top of the wart should have turned gray, which means the treatment solution has started to destroy the wart. Remove the gray, dead skin by filing it away with an emery board or pumice. You can get these at any grocery store or drugstore. Always wash your hands after touching the wart.

Repeat the treatment steps once a day until the wart is gone. It may take several weeks or even months. If the wart becomes sore, stop the treatment for a few days.

When should you visit your doctor?

See your doctor if you have warts on your face, genitals (private parts) or around your fingernails. Don't use wart treatments in these areas. See your doctor if you still have warts after 8 weeks of home treatment.

What treatments will the doctor suggest?

The doctor may suggest any of the following treatments:

a chemical solution that is stronger than home treatments liquid nitrogen to freeze the wart

burning the wart off with electricity

cutting the wart out or removing it with a laser

The wart may fall off within a few days. You may need more than one treatment. Some of these treatments may be painful or leave a scar.

Will the warts come back?

Treatment does not work every time. The virus may still be in your skin even if it looks like the wart is gone.

If you get more warts, treat them in the same way as before. Be very careful to follow the directions exactly.

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To reduce the spread of the virus, do not scratch, bite or chew the warts. CPhA assumes no responsibility for or liability in connection with the use of this information. For clinical use only and not intended for for use by patients. Once printed there is no quarantee the information is up-to-date. [Printed on: 03-03-2016 11:40 PM] RxTx, Compendium of Therapeutics for Minor Ailments © Canadian Pharmacists Association, 2016. All rights reserved

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