Dermatology

Molluscum Contagiosum

For the past 2 months a 4-year-old girl has developed discrete papular lesions in her left axilla. Some of the lesions are umbilicated.

How would you manage this patient?


Molluscum lesions on an arm
https://en.wikipedia.org/wiki/Molluscum_contagiosum

Etiology

Molluscum contagiosum is caused by a large DNA poxvirus that produces a wart like lesion. The incubation period is 2-7 weeks and lesions may last from months to years without treatment. 

Epidemiology

It is seen throughout the world and is most prevalent in school-age children. This common viral infection is seen with a higher frequency in tropical climates, where its incidence can approach 20% in children

Risk Factors

Cell-mediated immunity appears to be important in host defenses and immunocompromised patients may have extensive cases. It is also more common in patients with atopic dermatitis.

Transmission

Molluscum is most common in school-aged children and transmission is by fomites, close contact, and autoinoculation. In adults, transmission is often by sexual contact and any child with molluscum in the genital area should be investigated for possible sexual abuse.

Clinical Features

The lesions appear as small flesh-colored, dome-shaped, umbilicated papules that are very discrete. Occasionally there is a small rim of inflammation around the individual warts. A cheesy material may be extracted from the lesions and viral intracytoplasmic inclusion bodies may be seen in the keratinocytes of the skin (Henderson-Paterson bodies). Most commonly the lesions are on the face, eyelids, axilla, antecubital fossa, and upper thighs; palms and soles are spared. There have been no systemic or constitutional symptoms associated with molluscum in these individuals. Patients are usually asymptomatic but occasionally there may be some itching.

Molluscaklein.jpg
Typical flesh-colored, dome-shaped and pearly lesions
https://en.wikipedia.org/wiki/Molluscum_contagiosum

Diagnosis

  • Usually made by the characteristic appearance of the lesions
  • When necessary, histologic examination can confirm the clinical diagnosis.  H&E staining typically reveals keratinocytes containing eosinophilic cytoplasmic inclusion bodies (aka molluscum bodies or Henderson-Paterson bodies).

Treatment

  1. In the immunocompetent host, the lesions will go away without treatment although it may take months. The treatment modalities are often cumbersome and painful, so watchful waiting is advised. Occasionally lesions need to be removed for cosmetic reasons or to prevent spread to other family members.
  2. In immunocompromised hosts, lesions can persist much longer and be more numerous and widespread. In the HIV-infected patient, there have been multiple reports of recalcitrant molluscum lesions resolving only after initiation of highly active antiretroviral therapy
  3. Curettage- may require multiple visits and is painful
  4. Applying liquid nitrogen to individual lesions with an applicator.
  5. Applying salicylic acid, retinoic acid, cantharone (causes blistering)

References

  1. Prusad, Sudha. Molluscum Contagiosum. Pediatrics in Review April 1996 pg 118-19
  2. Silverberg NB, Sidbury R, Mancini AJChildhood molluscum contagiosum: Experience with cantharidin therapy in 300 patients.  J. Am. Acad. Dermatology 2000;43:503-507
  3. Smolinski K, and Yan A. How and When to Treat molluscum Contagiosum and Warts in Children.  Annals of Pediatrics March 2005
  4. Brown J, Janniger CK, Schwartz RA, Silverberg NB. Childhood molluscum contagiosum. Int J Dermatol 2006; 45:93.