Warts

Common warts (verrucae vulgaris) are caused by HPV types 1, 2, 4, and 7 and occasionally other types in immunosuppressed patients (eg, 75 to 77).

They are usually asymptomatic but sometimes cause mild pain when they are located on a weight-bearing surface (eg, bottom of the feet).

Common warts are sharply demarcated, rough, round or irregular, firm, and light gray, yellow, brown, or gray-black nodules 2 to 10 mm in diameter. They appear most often on sites subject to trauma (eg, fingers, elbows, knees, face) but may spread elsewhere. Variants of unusual shape (eg, pedunculated or resembling a cauliflower) appear most frequently on the head and neck, especially the scalp and beard area.

These warts are caused by HPV types 1, 2, and 4. They occur on the palms and soles.

Palmar and plantar warts are flattened by pressure and surrounded by cornified epithelium. They are often tender, and plantar warts can make walking and standing uncomfortable. They can be distinguished from corns and calluses Calluses and Corns Calluses and corns are circumscribed areas of hyperkeratosis at a site of intermittent pressure or friction. Calluses are more superficial, cover broader areas of skin, and are usually asymptomatic... read more by their tendency to pinpoint bleeding when the surface is pared away.

Flat warts are caused by HPV types 3 and 10 and occasionally 26 to 29 and 41. They are more common among children and young adults and develop by autoinoculation.

These warts are smooth, flat-topped, yellow-brown, pink, or skin-colored papules, most often located on the face and along scratch marks.

They generally cause no symptoms but are usually difficult to treat.

Mosaic warts are plaques formed by the coalescence of myriad smaller, closely set plantar warts. As with other plantar warts, they are often tender.

These warts are long, narrow, frondlike growths, usually located on the eyelids, face, neck, or lips. They are usually asymptomatic.

This morphologically distinct variant of the common wart is benign and easy to treat.

Periungual warts are caused by HPV types 1, 2, 4, and 7.

These warts appear as thickened, fissured, cauliflower-like skin around the nail plate. They are usually asymptomatic, but the fissures cause pain as the warts enlarge. Patients frequently lose the cuticle and are susceptible to paronychia Acute Paronychia Paronychia is infection of the periungual tissues. Acute paronychia causes redness, warmth, and pain along the nail margin. Diagnosis is by inspection. Treatment is with antistaphylococcal antibiotics... read more .

Periungual warts are more common among patients who bite their nails or who have occupations where their hands are chronically wet such as dishwashers and bartenders.

Genital warts Human Papillomavirus (HPV) Infection Human papillomavirus (HPV) infects epithelial cells. Most of the > 100 subtypes infect cutaneous epithelium and cause skin warts; some types infect mucosal epithelium and cause anogenital warts... read more are caused by HPV type 6 or 11 (most commonly) and by types 1a, 2, 4, 7, 16, 18, 27b, 27, 33, 38, 40, 42, 43, 44, 54, 57b, 57c, 61, 72, 81, and 89 (1 Genital warts reference Warts are common, benign, epidermal lesions caused by human papillomavirus infection. They can appear anywhere on the body in a variety of morphologies. Diagnosis is by examination. Warts are... read more ).

These warts manifest as discrete flat to broad-based smooth to velvety papules to rough and pedunculated excrescences on the perineal, perirectal, labial, and penile areas. They are usually asymptomatic, but perirectal warts often itch.

Infection with high-risk HPV types (most notably types 16 and 18 but also types 31, 33, 35, and 39) is the main cause of cervical cancer Cervical Cancer Cervical cancer is usually squamous cell carcinoma; adenocarcinoma is less common. The cause of most cervical cancers is human papillomavirus (HPV) infection. Cervical neoplasia is often asymptomatic... read more .

In immunocompetent patients, common warts usually spontaneously regress within 2 to 4 years, but some linger for many years. Numerous treatments are available. Destructive methods include electrocautery, cryosurgery with liquid nitrogen, and laser surgery. Salicylic acid preparations are also commonly used.

Which method is used depends on the location and severity of involvement.

Salicylic acid (SCA) is the most common topical agent used. SCA is available as a liquid or plaster or impregnated within tape. For example, SCA 17% liquid can be used on the fingers, and SCA 40% plaster can be used on the soles. Patients apply SCA to their warts at night and leave it on for 8 to 48 hours depending on the site. SCA may be occluded with tape to enhance penetration. SCA may be compounded with 5-fluorouracil in various formulations for treatment of common warts on the palms and soles.

Cantharidin (0.7% on thin-skinned areas and 1% on thicker-skinned areas) can be used alone or in combination with SCA 30% and podophyllum 5% in a collodion base. Cantharidin alone is removed with soap and water after 6 hours; cantharidin with SCA or podophyllum is removed in 2 hours. The longer these agents are left in contact with the skin, the more brisk the blistering response.

Cryosurgery is painful but extremely effective. Electrodesiccation with curettage, laser surgery, or both is effective and indicated for isolated lesions but may cause scarring.

Recurrent or new warts occur in about 35% of patients within 1 year; therefore, methods that scar should be avoided as much as possible so that multiple scars do not accumulate. When possible, scarring treatments are reserved for cosmetically unimportant areas and recalcitrant warts.

Treatment of filiform warts is removal with scalpel, scissors, curettage, or liquid nitrogen. Liquid nitrogen should be applied so that up to 2 mm of skin surrounding the wart turns white. Damage to the skin occurs when the skin thaws, which usually takes 10 to 20 seconds. Blisters can occur 24 to 48 hours after treatment with liquid nitrogen.

Care must be taken when treating cosmetically sensitive sites, such as the face and neck, because hypopigmentation or hyperpigmentation frequently occurs after treatment with liquid nitrogen. Patients with darkly pigmented skin can develop permanent depigmentation.

Treatment of flat warts is difficult, and flat warts are often longer-lasting than common warts, recalcitrant to treatments, and, in cosmetically important areas, make the most effective (destructive) methods less desirable.

Usual first-line treatment is daily tretinoin (retinoic acid 0.05% cream). If peeling is not sufficient for wart removal, another irritant (eg, 5% benzoyl peroxide) or 5% SCA cream can be applied sequentially with tretinoin. Imiquimod 5% cream can be used alone or in combination with topical agents or destructive measures. Topical 5-fluorouracil 1% or 5% cream can also be used.

Treatment of plantar warts is vigorous maceration with 40% SCA plaster kept in place for several days. The combination of 17% SCA and 2.5% 5-fluorouracil under tape occlusion for 8 to 12 hours is also effective. The wart is then debrided while damp and soft, followed by destruction by freezing or using caustics (eg, 30 to 70% trichloroacetic acid).

Other destructive treatments (eg, CO2 laser, pulsed-dye laser, various acids) are often effective.

Combination therapy with liquid nitrogen and imiquimod 5% cream, tretinoin, or SCA is effective and usually safer than liquid nitrogen alone or cautery.

Using liquid nitrogen and cautery to treat periungual and lateral finger warts should be done carefully because overly aggressive treatment can cause permanent nail deformity and rarely nerve injury.

Several methods are available for the treatment of recalcitrant warts, but long-term value and risks are not fully known.

Intralesional injection of small amounts of a 0.1% solution of bleomycin in saline often cures stubborn plantar and periungual warts. However, Raynaud syndrome Raynaud Syndrome Raynaud syndrome is vasospasm of parts of the hand in response to cold or emotional stress, causing reversible discomfort and color changes (pallor, cyanosis, erythema, or a combination) in... read more or vascular damage may develop in injected digits, especially when the solution is injected at the base of the digit, so caution is warranted.

Intralesional injection of Candida antigen has also been reported to be moderately effective for recalcitrant warts.

Interferon, especially interferon alfa, given intralesionally (3 times/week for 3 to 5 weeks) or intramuscularly, has also cleared recalcitrant skin and genital warts.

Extensive warts sometimes abate or clear with oral isotretinoin or acitretin.

The 9-valent HPV vaccine has been reported as useful for recalcitrant warts in children, but efficacy of this intervention is not proved (2 Treatment references Warts are common, benign, epidermal lesions caused by human papillomavirus infection. They can appear anywhere on the body in a variety of morphologies. Diagnosis is by examination. Warts are... read more ).