Molluscum contagiosum

Molluscum contagiosum is a viral skin infection seen most often in normal immunocompetent children. They usually present as single or multiple (usually no more than 20), discrete, smooth, pearly papules with a classic dimple (van der Wouden et al., 2006) (Figure 12.5). The infection is caused by a pox virus and follows contact with infected people or contaminated objects. They occur worldwide but are more common in areas with warm climates with an association with swimming pool use, age, living in close proximity and skin-to-skin contact while gender, seasonality and hygiene show no association (Braue et al., 2005). Infection is rare under the age of 1 year and most common in the 2- to 5-year age group. Affected people and the parents of affected children frequently seek help for social reasons; for children name calling and bullying are not uncommon. A large proportion of the parents interviewed by Braue et al. (2005) reported that they were moderately or greatly concerned and these concerns focused on physical issues such as scarring, itching and the chance of spread to peers, pain and the effects of treatments.

The estimated incubation period varies from 14 days to 6 months. The lesions grow slowly and can reach a diameter of 5–10 mm in 6–12 weeks. They usually resolve spontaneously within 6–9 months without leaving scars but the duration of individual lesions and the entire episode can be very variable with some lasting for 3–4 years (van der Wouden et al., 2006) and the virus may spread to other areas of skin. Trauma such as scratching may result in pus, crusting and the destruction of the lesion.

It should be noted that there is also a sexually transmitted variant which occurs in genital, perineal, pubic and surrounding skin. Molluscum contagiosum has also been observed with other diseases in people with a damaged immune system and people with HIV infection are particularly prone (van der Wouden et al., 2006). As immunodeficiency progresses in HIV-infected individuals, they become more common and resistant to treatment. Multiple lesions on atypical areas such as the face and neck are often seen. There is limited data on the disease course in this group.

Management

1. The option of no treatment is reasonable especially in young children (van der Wouden et al., 2006).
2. Cryotherapy can be very effective but is painful and not usually tolerated by children.
3. Topical therapies include salicylic acid or podophyllotoxin cream. Crystacide cream can be used off license and 5% Imiquimod cream can be used in difficult cases.
4. A recent review of treatments could find no reliable evidence for any of the treatments currently used (van der Wouden et al., 2006) and recommends that until better evidence on treatment options is found, lesions should be left to heal naturally.