At the recent Dermatology Conference held in Cape Town, Dr Lushen Pillay, head of Dermatology Division at the Helen Joseph Hospital and dermatologist in private practice, in Johannesburg, presented on molluscum contagiosum.
This session was sponsored by Glenmark. The following article is based on Dr Pillay’s presentation.
Molluscum contagiosum (MC) is a viral skin condition caused by the molluscum contagiosum virus (MCV). It is characterised by single or multiple papules or bumps. It can appear on various parts of the body and affects single or multiple sites.
MC has an incubation period of 14 days to six months. The individual lesion is a shiny, pearly white, hemispherical, umbilicated papule, which may show a central pore. Size ranges from 1mm enlarging to 5-10mm in 6-12 weeks. Rarely, a lesion may become much larger if solitary. The agminate form/ giant molluscum are plaques composed of many small lesions. After trauma, or spontaneously after several months, inflammatory changes result in suppuration, crusting and eventual destruction of the lesion.
MC is highly contagious and can cause psychological distress. If left untreated, lesions can persist for months to years.
The infection can spread to other areas of the body and untreated lesions might become larger. There may be inflammation due to secondary bacterial infection. Be aware of complications in immunocompromised individuals.
Most treatment options are not very effective but include:
- Physical removal with cryotherapy, curettage (scraping), or laser therapy
- Chemical treatment with Cantharidin (beetle juice)
- Topical treatments with imiquimod or tretinoin cream stimulate immune response, helps with lesion clearance.
First-line therapy consists of topical agents, used to produce mild to moderate inflammation and therefore stimulate the development of an immune response. These are strong irritants which can cause pain, blistering and scarring but with careful application and appropriate dilution can increase lesion clearance. Second-line treatment consists of cryotherapy, which is effective and commonly used in older children and adults.
It needs to be repeated at 3-4 weekly intervals. Carbon dioxide or pulsed dye lasers are useful but can cause scars. Photodynamic therapy is another option.
Curettage can cause scarring. Clearance rate is reduced if there are many lesions. Third-line treatments include cidofovir and intravenous paclitaxel for severe disease in immunocompromised. Potassium hydroxide (KOH) solution topical treatment has been shown to be effective and safe. KOH solution causes destruction of MC-infected cells but should only be applied directly to lesions and not on healthy skin. Molucide gel with applicator contains 10% KOH in gel form and has a novel pin-point applicator, which enables greater precision in administration. Around 75% of 32 patients treated with molucide had complete clearance within five days, while 84% of the patients had more than 75% of lesions cured in five days. It is easy to use and is indicated for adults and children >2 years of age.