Molluscum contagiosum - Anogenital in
Molluscum contagiosum is a viral skin infection caused by a DNA poxvirus. It manifests as smooth, firm papules with a central umbilication. Genital lesions are most commonly spread by sexual contact, and papules are most commonly seen on the shaft of the penis. However, lesions may also be found on the scrotum, in the pubic area, and on the inner aspect of the thighs.
Molluscum contagiosum may also be spread by direct contact (most often in children) and autoinoculation (ie, shaving). Infections have also been associated with swimming pool facilities via fomites.
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.
In cases of underlying immunodeficiency, such as HIV disease, molluscum may be widespread or large, atypical papules and/or plaques may be seen.
B08.1 – Molluscum contagiosum
40070004 – Molluscum contagiosum
Differential Diagnosis & Pitfalls
- Condyloma acuminatum can look similar if small.
- Herpes simplex virus lesions can resemble molluscum with a central umbilication, but lesions are fluid-filled rather than solid as in molluscum contagiosum.
- Fordyce spots
- Milia tend to be whiter in color and concentrated on the face.
- Lobular capillary hemangioma (pyogenic granuloma) is obviously vascular with frequent ulceration.
- Lichen planus lesions are purple, pruritic, planar papules that can also spread in a linear pattern.
- Pearly penile papule lesions, in most cases, are on the coronal sulcus but can be found elsewhere on the penis. Consider a diagnosis of pearly penile papules even if the lesions reside outside of the coronal sulcus, especially if the lesions are unresponsive to treatment for molluscum contagiosum.
- Cryptococcal infection in an immunocompromised host
- Lichen nitidus
- Bowenoid papulosis
- Papular acantholytic dermatosis