Molluscum contagiosum is a fairly common skin infection caused by a virus. It 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 nearby skin. Molluscum contagiosum also spreads through person-to-person contact and contact with infected objects.
Though most common in children, molluscum contagiosum can affect adults as well — particularly those with weakened immune systems. Adults with a healthy immune system can develop molluscum contagiosum from sexual activity with an infected partner.
Left untreated, the bumps usually disappear in 6 months to 2 years
Cited from the Mayo Clinic & the American Academy of Dermatology