Molluscum contagiosum (mo-LUS-kum kun-tay-jee-OH-sum) is a relatively common viral infection of the skin that results in round, firm, painless bumps ranging in size from a pinhead to a pencil eraser. If the bumps are scratched or injured, the infection can spread to surrounding skin.

Though most common in children, molluscum contagiosum can affect adults as well — particularly those with weakened immune systems. In adults, molluscum contagiosum involving the genitals is considered a sexually transmitted infection (STI).

Molluscum contagiosum spreads through direct person-to-person contact and through contact with contaminated objects. The bumps associated with molluscum contagiosum usually disappear within a year without treatment but doctor-assisted removal is also an option.