An Update on the Clinical Management of Cutaneous Molluscum Contagiosum

Harrison P. Nguyen, BA; Stephen K. Tyring, MD, PhD, MBA


Skin Therapy Letter. 2014;19(2) 

In This Article

Clinical Management

In nearly all immunocompetent individuals, molluscum contagiosum is a self-limiting disease that will spontaneously resolve, usually without scarring. Allowing this natural resolution of infection without therapeutic intervention is an important and effective treatment strategy that also minimizes healthcare costs. Regardless of whether treatment is sought, it is imperative that the clinician advises the patient to avoid swimming pools, bathing with others, sharing of towels, and activities requiring physical contact with others.

Current therapeutic intervention in the treatment of molluscum contagiosum is intended merely to accelerate the eradication process. A systematic review in 2009 studied the efficacy of current therapeutic options for nongenital molluscum contagiosum and concluded that there was insufficient evidence to support the use of any treatment as being definitively effective.[8] Nevertheless, for the rapid resolution of individual lesions, clinical experience advocates the use of curettage, cryotherapy, and some topical agents. Therefore, the patient may wish to seek treatment for a variety of reasons, including: alleviating pruritus; minimizing autoinoculation as well as transmission to others; addressing cosmetic concerns; and preventing scarring, secondary infection, or bleeding of the lesions.[8] Patients with sexually transmitted molluscum contagiosum should receive early treatment to prevent the spread of infection to future sexual partners. Early treatment is also indicated for immunosuppressed patients whose infections can become severe. Prior to beginning treatment, the clinician should conduct a full-body skin examination to identify all lesions; failure to treat all lesions may lead to continued infection and autoinoculation.

Curettage, cryotherapy, and cantharidin are considered to be firstline treatment strategies due to their popularity and established efficacy for resolution of individual lesions. Curettage involves the physical removal of lesions with the use of a curette and is the preferred choice of treatment in the Netherlands.[8] Risk factors for treatment failure include a high number of lesions and concomitant atopic dermatitis. Topical anesthetics can be used to reduce the pain and discomfort associated with curettage, which can be disturbing for some children. The development of small, depressed scars following curettage is possible and should be discussed with the parents or guardians prior to treatment. Cryotherapy entails the use of a cotton-tipped swab dipped in liquid nitrogen that is applied to individual lesions for 6 to 10 seconds each. A 2010 randomized trial comparing the efficacy of cryotherapy with the immunomodulator imiquimod found cryotherapy to be effective in completely curing all patients and yielding more rapid resolution than imiquimod.[29] However, cryotherapy also had an increased occurrence of adverse effects, such as pain, bullae, dyspigmentation, and mild scarring. Cantharidin – the most popular method of treatment among American dermatologists – is a topical blistering agent that is applied directly to the lesions, usually with the blunt end of a cotton swab.[8] To prevent further autoinoculation or transmission, the site of treatment should then be covered with a bandage and washed with soap and water 2 to 6 hours after application. Treatments can be repeated every 2 to 4 weeks and are contraindicated for lesions located on the face, genitalia, or perianal regions. A retrospective study found 90% of children treated with cantharidin for molluscum experienced lesion clearance; the average number of patient visits to achieve complete resolution was 2.1.[6] About 95% of parents of children participating in the study stated that they were satisfied with the treatment and would be willing to have their child treated again with cantharidin. Common side effects that were observed include transient burning, erythema, pain, and pruritus.

Several second-line therapies have been described, which include (but are not limited to): imiquimod, sinecatechins ointment, podophyllin, potassium hydroxide, salicyclic acid, topical retinoids, oral cimetidine, pulsed dye lasers, and silver nitrate. However, the efficacy of these treatment strategies in healthy patients is controversial. A 2009 review by van der Wouden et al and a 2006 review by Brown et al analyze comparative studies involving the aforementioned second-line treatments.[8]

Immunocompromised patients can develop severe, persistent infection by not only MCV but also opportunistic pathogens. Treatments that lead to wound formation, such as curettage, should be avoided since wounds elevate the risk of additional infection. Instead, imiquimod applied 3 nights per week is recommended.[30] In our investigational center, the authors have achieved successful reduction of genital lesions with the use of 0.05% ingenol mebutate gel as spot treatment in a renal transplant patient. In HIV positive patients, recalcitrant lesions are sometimes resolved only after initiation of highly active antiretroviral therapy (HAART).[31] Clearance of recalcitrant, refractory lesions in HIV positive patients has been achieved through the use of intravenous cidofovir, a nucleotide analog of deoxycytidine monophosphate.[32] However, systemic cidofovir can be toxic on the kidneys, so topical cidofovir is currently being explored as a potential therapeutic agent. The authors achieved complete resolution of a severe case of molluscum contagiosum on the face of an HIV patient in 2 months following treatment with topical cidofovir compounded into a 2% ointment.

Atopic dermatitis patients are at greater risk for scar formation with increasing number of lesions, so curettage is not advisable. Prior to treatment of the molluscum lesions, the physician should address the atopic dermatitis with corticosteroids and antihistamines. Other immunomodulatory agents may be useful in long-term therapy of atopic dermatitis, but these drugs may facilitate MCV infection.[26] Javed and Tyring, in a published case report, achieved complete remission of molluscum contagiosum in an atopic pediatric patient using ingenol mebutate 0.015% gel.[33] Not only was there complete clearance of lesions in the treated area, but untreated lesions located in distant regions also resolved. Ingenol mebutate has been approved by the US FDA for the treatment of actinic keratosis. The proposed mechanism involves lesion necrosis and neutrophil-mediated, antibodydependent cellular cytotoxicity.[34]

Periocular lesions should be referred to an ophthalmologist for further treatment.