What causes it?

Molluscum contagiosum is a common skin infection caused by a virus in the pox virus family. It is seen most commonly in children and is spread through skin-to-skin contact or through contact with fomites such as sharing towels. It is often spread from the initial site of infection to other sites in the same child (autoinoculation). A second peak of molluscum contagiosum is seen in young adults as a sexually transmitted disease with lesions primarily in the suprapubic area. Sporadic cases can occur in healthy adults as well as in association with HIV or other forms of immunosuppression.  

What does it look like?

Molluscum presents as pearly, skin-coloured to pink papules. The classic lesions have a central umbilication. Molluscum lesions are 2-8 mm in size and are usually asymptomatic. They can occur in clusters, in linear configurations, or as solitary lesions. Although they can be seen anywhere, they are most common in areas of rubbing or moist skin such as the axilla, popliteal fossae, and groin. The lesions sometimes cluster in areas of atopic dermatitis (eczema) and may themselves cause dermatitis in the surrounding skin. They may develop significant erythema (redness) and some tenderness, which usually represents the body developing an immune reaction to the infection and may signal impending clearance of the lesions. They may leave pitted scars after resolution. 

How are they treated?

Most molluscum lesions resolve spontaneously without treatment over the course of a year or more. Parents are often quite anxious about the lesions and treatment may be requested. The treatment can hasten the resolution, but aggressive therapy can lead to increased scarring. In-office therapies including cantharidin, which can be applied painlessly and then washed off after 2-4 hours. This may include a blistering reaction. The degree of blistering can be variable, so only a few should be treated at first visit. Liquid nitrogen can also be used, but is painful, especially for young children. At home treatment include mild irritants such as vinegar, tea-tree, or hydrogen peroxide. 

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