Contagiosum

Contagiosum, more commonly referred to as molluscum contagiosum, is a viral skin infection caused by molluscum contagiosum virus (MCV), a member of the Poxviridae family. Four MCV types (MCV-1 to MCV-4) have been identified. The disease is generally mild and self-limited, though lesions can persist longer in adults and in immunocompromised individuals.

Transmission occurs primarily through direct skin-to-skin contact or contact with contaminated objects. In children, it commonly spreads in schools and households. In adults, genital and perineal involvement can occur through sexual contact. Autoinoculation from one body area to another is also possible.

Clinically, molluscum contagiosum presents as small, firm, dome-shaped papules that are flesh-colored and 2–5 mm in diameter, often with a central umbilication. Lesions may itch or become irritated. In children, lesions typically appear on the trunk, limbs, and face; in adults, they more often involve the genital area or lower abdomen. Complications include secondary bacterial infections and, rarely, widespread dissemination in severely immunocompromised individuals.

Diagnosis is usually clinical. Histology can show intracytoplasmic molluscum bodies (Henderson-Paterson bodies) within keratinocytes. PCR testing can be used in atypical cases or for research purposes.

Treatment is often not required, as infections resolve over several months to a few years. When treatment is desired or warranted, options include cryotherapy, curettage, cantharidin (in controlled settings), and topical therapies such as cidofovir or retinoids, with imiquimod having variable results. In HIV or other immunocompromised patients, management may be more extensive.

Prevention focuses on minimizing spread: avoid scratching lesions, cover active papules, and refrain from sharing towels or other personal items. Good general hygiene and, in adults with genital lesions, safe-sex practices can reduce transmission.