Molluscum contagiosum is a fairly common viral infection of the skin caused by a pox virus. The virus causes 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 and can be severe in eczema patients or patients with compromised skin.

Though most common in children, molluscum contagiosum can affect adults as well, particularly those with weakened immune systems. In adults with an otherwise normal immune system, molluscum contagiosum involving the genitals is considered a sexually transmitted infection.

Molluscum contagiosum spreads through direct person-to-person contact and through contact with contaminated objects.