This summary discusses adult patients. Molluscum contagiosum in children is addressed separately.

Molluscum contagiosum is a viral skin infection caused by a DNA poxvirus. It manifests as smooth, firm papules with central umbilication. Molluscum contagiosum may be spread by direct skin-skin contact (most often in children), via fomites (eg, towel, gym equipment), via autoinoculation, or via sexual transmission in adults.

In adults, molluscum contagiosum is commonly found on the mons pubis, the genitalia, perineum, inner thighs, and lower abdomen. The distribution in children is on the trunk and extremities. In underlying immunodeficiency, such as HIV disease, molluscum may be widespread or large, atypical papules and/or plaques may be seen.

Many cases are asymptomatic, but there can be surrounding irritation and pruritus.

In the immunocompetent host, the disease tends to be self-limited, but papules may persist for several months and up to 2 years before disappearing.

Immunosuppressed patients and those with HIV disease / AIDS are at particular risk of molluscum contagiosum infection, with a prevalence of 5%-18%. The number of lesions is inversely correlated with the CD4 count, and the presence of molluscum contagiosum lesions can actually indicate an AIDS diagnosis. Molluscum contagiosum has also been reported in association with several other immunosuppressed states including malignancies, severe combined immunodeficiency, organ and bone marrow transplants, and chemotherapy recipients. Sarcoidosis and atopic dermatitis also predispose patients to molluscum contagiosum infections, most likely due to abnormal T-cell immunity.