Warts and molluscum contagiosum

HPV infection is highly specific for epidermis, especially extremities, palms, and soles, but also the scalp and mucosal surfaces such as the mouth, larynx, genital areas, and rectal mucosa. Some types of HPV have a predilection for infection in certain locations in the body (Table 26-1). For example, flat warts are seen mostly on the face and hands of children and are often caused by HPV types 3 and 10 (Fig. 26-1A). Common warts occur most often on the fingers and periungual skin and are commonly due to HPV types 2, 4, and 29 (Fig. 26-1B). Warts in immunosuppressed patients are caused by HPV type 8 and others (Fig. 26-1C).

Certain types of HPV infection have been associated with the development of malignancy. Although bowenoid papulosis is not considered a premalignancy, it may be associated with an increased risk of cervical cancer. Carcinomas of the conjunctiva, cornea, nasal cavities, oral cavity, esophagus, and plantar surface of the foot also have been reported in association with various types of HPV.

Carcinogenic wart types include the following: 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, and 69.

EV is a rare, inherited disorder in which cutaneous HPV infection is generalized and persistent. Most cases are autosomal recessive, but autosomal dominant and X-linked dominant forms are also reported. It is caused by mutations in either the EVER1 or EVER2 genes. The lesions are either flat warts or reddish-brown plaques, often developing in sun-exposed areas (Fig. 26-2A). Malignant change occurs in about 10% of cases, but metastasis is uncommon. HPV types 5 and 8 are most commonly seen in EV patients, although several other HPV types may also been seen.

Gül U, Kiliç A, Gönül M, et al: Clinical aspects of epidermodysplasia verruciformis and review of the literature, Int J Dermatol 46:1069–1072, 2007.

HPV infection occurs after exposure to humans or animals with HPV infection. The most common mode of transmission is through touch or contact from an individual infected with HPV, although HPV may also survive on inanimate objects for unknown amounts of time. Small abrasions or cracks in the skin of exposed persons allow the virus to penetrate. Such infection may commonly occur at a swimming pool, where chlorinated water and rough concrete surfaces may abrade the skin, or at other public places. Genital warts may be transmitted through sexual intercourse. People who work with meat, fish, and poultry also commonly have warts in the hand and forearm area, which are thought to be promoted through microinjuries sustained during processing of animals or fish, as well as from prolonged immersion of the skin in water.

Autoinoculation is another form of transmission. Periungual warts are often found in persons who have a habit of biting their cuticles, for example. Presumably the excoriated areas are more hospitable to virus, but spread of a single common wart is also possible. Flat warts in the beard area or on the legs may be spread by shaving.

Yes, especially if they are injured. Such injury may happen if the warts are in a location traumatized by shaving or scratching. This reaction is known as the Koebner phenomenon. (The Koebner reaction is also present in skin conditions that have no known viral cause, such as psoriasis and lichen planus.) Close approximation of two surfaces, where one surface is affected and the opposing surface is unaffected, is also associated with an increased likelihood of spreading (e.g., adjacent toe surfaces; Fig. 26-2B).

No one is certain how to avoid the development of warts.

There are now vaccines available to help prevent warts. Gardasil® helps to prevent genital warts in men and women. Cervarix® helps prevent cervical cancer in women.

The term plantar wart refers to a location rather than to a pattern of behavior. Plantar warts are simply warts on the plantar aspect (sole) of the foot. Warts in this location have a unique appearance from being compressed by the pressure of walking.

For reasons that are not entirely clear, plantar warts are more difficult to eradicate. Excision by scalpel or carbon dioxide laser often results in scarring, and recurrence is common. Repeated liquid nitrogen treatment may be painful, inconvenient, and costly. Vascular pulsed dye laser is effective and not as painful or debilitating as liquid nitrogen treatment. Home treatments with salicylic acid pads, along with judicious trimming to maintain comfort, seem to be most helpful. Glutaraldehyde, which produces a brown discoloration of treated surfaces, has also been used successfully.

Immunocompromised individuals, such as those with HIV infection or cancer, or transplant patients on immunosuppressive drugs are more susceptible to warts than others. Sexual intercourse at an early age is a known risk factor for acquiring genital warts. Children with atopic dermatitis may have warts that are more extensive and more difficult to eradicate.

Harwood CA, Perrett CM, Brown VL, et al: Imiquimod cream 5% for recalcitrant cutaneous warts in immunocompromised individuals, Br J Dermatol 152:122–129, 2005.

Clinical examination is sufficient for evaluation. Treatment goals should be to eliminate symptomatic warts. Sexual partners of patients with EGWs should be evaluated for warts or other sexually transmitted diseases. Women with EGWs should have cervical cytologic screening. HPV detection and EGW typing are not currently required for diagnosis or management. In minors, the presence of EGWs should prompt a consideration of sexual abuse.

Lacey CJ: Therapy for genital human papillomavirus-related disease, J Clin Virol 32:S82–S90, 2005.

Over-the-counter methods for eliminating warts include topical applications of acids such as salicylic or lactic acid. These may be in a liquid form or may be incorporated into plasters (Table 26-2). When choosing a treatment plan for warts, the physician’s primary concern should be to not make the treatment worse than the warts. For example, a treatment worse than the disease would be to excise and suture a wart on the weight-bearing surface of the foot and then have the wart recur in the middle of a painful scar. Sometimes, the best treatment is benign neglect. Resistance and recurrence are common with all treatments.

• Blistering (liquid nitrogen, cantharidin, topical 5-fluorouracil, bleomycin) (Fig. 26-3A)

Fairy ring warts, or satellite warts, are annular warts that may develop following any treatment that produces blisters (Fig. 26-3B).

No single treatment method may be relied upon to eliminate warts permanently. Treatment choice must depend on the age of the patient, location, appearance, and symptoms of the wart:

No. Molluscum contagiosum is a viral infection of the skin produced by a poxvirus that is more closely related to the virus that produces smallpox. Like warts, they are more common in children and immunocompromised individuals, and can be sexually acquired. They may occur anywhere on the skin surface and present as firm, skin-colored umbilicated papules with a central core of keratin (Fig. 26-4A). Some lesions may demonstrate an intense host response (Fig. 26-4B). Many of the same treatments effective in treating warts are effective in treating molluscum contagiosum.

Scheinfeld N: Treatment of molluscum contagiosum: a brief review and discussion of a case successfully treated with adapelene, Dermatol Online J 13:15, 2007.