Atlas of pathophysiology, 2 Edition

Part II - Disorders

Skin Disorders

Warts

Warts, also known as verrucae, are common, benign, viral infections of the skin and adjacent mucous membranes. The prognosis varies; some warts disappear spontaneously, some readily with treatment, and others need vigorous and prolonged treatment.

Age Alert

Although their incidence is highest in children and young adults, warts may occur at any age.

Causes

·   Human papilloma virus (HPV)

·   Probably transmitted through direct contact; autoinoculation

Pathophysiology

HPV replicates in the epidermal cells, causing irregular thickening of the stratum corneum in the infected areas. People who lack virus-specific immunity are susceptible.

Signs and symptoms

·   Common (verruca vulgaris): rough, elevated, rounded surface; appears most frequently on extremities, particularly hands and fingers; most prevalent in children and young adults

·   Filiform: single, thin, threadlike projection; commonly occurs around the face and neck

·   Periungual: rough, irregularly shaped, elevated surface; occurs around edges of fingernails and toenails; when severe, may extend under the nail and lift it off the nail bed, causing pain

·   Flat (juvenile): multiple groupings of up to several hundred slightly raised lesions with smooth, flat, or slightly rounded tops; common on the face, neck, chest, knees, dorsa of hands, wrists, and flexor surfaces of the forearms; usually occurs in children but can affect adults; distribution is often linear because these can spread from scratching or shaving

·   Plantar: slightly elevated or flat; occurs singly or in large clusters (mosaic warts), primarily at pressure points of the feet; typically cause pain with weight bearing

·   Digitate: fingerlike, horny projection arising from a pea-shaped base; occurs on scalp or near hairline

·   Condyloma acuminatum (moist wart): usually small, flesh-colored pink to red, moist, soft; may occur singly or in large cauliflower-like clusters on penis, scrotum, vulva, or anus; may be transmitted through sexual contact; not always venereal in origin

Diagnostic test results

·   Sigmoidoscopy when anal warts are recurrent rules out internal involvement necessitating surgery.

·   Application of 5% acetic acid turns warts white if they're papillomas.

Treatment

Electrodesiccation and curettage

·   High-frequency electric current to destroy the wart, surgical removal of dead tissue at the base

·   Effective for common, filiform and, occasionally, plantar warts

·   More effective than cryosurgery

Cryotherapy

·   Liquid nitrogen kills the wart; resulting dried blister peeled off several days later

·   If initial treatment unsuccessful, can be repeated at 2- to 4-week intervals

·   Useful for periungual warts or for common warts on face, extremities, penis, vagina, or anus

Acid therapy (primary or adjunctive)

·   Applications of plaster patches impregnated with acid (such as 40% salicylic acid plasters) or acid drops (such as 5% to 16.7% salicylic acid in flexible collodion) every 12 to 24 hours for 2 to 4 weeks

·   Hyperthermia for verruca plantaris

For genital warts

·   Cryotherapy

·   Podophyllin in tincture of benzoin; may be repeated every 3 to 4 days (avoid using this drug on pregnant patients)

·   25% to 50% trichloroacetic acid applied to wart and neutralized with baking soda or water when wart turns white

·   Carbon dioxide laser therapy

Other

·   Antiviral drugs under investigation

·   If immunity develops, possible resolution without treatment

·   Imiquimod ointment

P.395

CROSS SECTION OF A WART

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Clinical Tip

Periungual Warts

Warts around the edges of fingernails and toenails are rough, irregularly shaped, and have an elevated surface. A severe wart may extend under the nail and lift it off the nail bed, causing pain.

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