This article is more than 5 years old. Information may no longer be current.
A 10-year-old with pruritic pink lesions on the arms and abdomen
Click Here to Manage Email Alerts
A 10-year-old girl presents to your clinic with a pruritic red plaque on her arm and a persistent asymptomatic eruption on her trunk and arms for several months. Her mother recalls the eruption starting near the end of summer as a few small pink and skin-colored “bumps” on her right arm. Over the past several months, she developed several more similar-appearing lesions. The eruption remained asymptomatic until three weeks ago when her mother noted a new, moderately pruritic, erythematous, scaling eruption involving the right antecubital fossa involving the same distribution as the initial “bumps.” On exam involving the abdomen, arms and axillae are numerous clustered 1-3 millimeter dome-shaped translucent skin colored papules. In her right antecubital fossa there is an erythematous, scaly plaque within which are several pearly, umbilicated papules.
What is your diagnosis?
Diagnosis: Molluscum contagiosum (MC) with “molluscum dermatitis.”
Discussion: MC is a benign, very common childhood viral exanthem that can be associated with a secondary dermatitis known as “molluscum dermatitis.” MC is caused by a double stranded DNA pox virus known as the molluscum contagiosum virus. It is most commonly seen in early childhood but is also found in older children who participate in contact sports such as wrestling as well as immunocompromised patients. It occurs in older, sexually active patients involving the genital region. Lesions can last several months to years at which time the immune system recognizes the virus as foreign and responds appropriately.
Clinically, the classic lesions are clustered small (1-4 mm), smooth, dome-shaped, translucent, skin-colored or pink umbilicated papules. They can occur in any location but are often found in intertriginous regions such as the groin, buttocks and axillae. This is likely secondary to auto-inoculation. The lesions have a central white core known as a molluscum body which patients often refer to as a “seed.” When the molluscum body is extruded, the lesion resolves within several days.
Marissa J. Perman is a third-year dermatolology resident at the University of Cincinnati.
The virus is spread via contact with infected individuals. Swimming pools have been implicated. The virus may also be spread through sexual contact. Young adults with MC should be screened for other sexually transmitted diseases and educated about safe sex practices. However, mollusca in the groin area in children are almost exclusively due to auto-inoculation rather than sexual abuse.
Some patients may develop an associated dermatitis with the MC known as “molluscum dermatitis,” thought to be a delayed hypersensitivity reaction to the virus. The inflammatory nature of this associated eruption may be confused with “eczema” or a secondary infection.
Alternatively, patients with atopic dermatitis are more susceptible to MC, likely secondary to their impaired barrier function and altered skin immune response, leading in some cases to a more severe course. MC in these patients tends to be more inflamed. MC lesions often become inflamed prior to spontaneous resolution at which point they do not require treatment. Individual molluscum lesions become red, enlarged, crusted and sometimes pustular, resembling a “boil,” before they spontaneously resolve.
Molluscum, while harmless to the individual, can create high anxiety for the patient and family due to the increasing number of lesions as well as the social stigmatization. When they start to regress they may be pruritic and painful. Larger lesions can leave pitted scars. They are also highly contagious, and it is rare for siblings or close contacts to avoid becoming infected. Therefore, many families seek treatment. Watchful waiting is an acceptable option as the lesions will eventually resolve without therapy. The most common therapies are destructive and include curettage, cryotherapy or cantharadin. Curretage is well-tolerated in patients who receive application of topical anesthetic cream (lidocaine or a lidocaine/prilocaine mixture) applied under occlusion for at least one hour prior to treatment. Cryotherapy is a good option for older children with a limited number of lesions. Application of cantharadin, a phosphodiesterase inhibitor that leads to blistering, is painless, however severe blistering and pain can develop several hours to days after treatment. Some pediatric dermatologists also suggest patients or their parents treat the lesions by extracting the molluscum body with a toothpick. Less well-documented but popular treatments include topical imiquimod cream (expensive), oral cimetidine, and injections of candida antigen. Various medications are for sale on the internet, but none of these has any evidence-based data showing that they are effective or safe.
The associated dermatitis is often mistaken for “eczema” but its asymmetric distribution and late-onset is atypical for atopic dermatitis. Careful observation will show the presence of molluscum lesions within the red, scaly plaques. The dermatitis does not require therapy unless symptomatic. The most common symptom is pruritus, which can be managed locally by mild to mid potency topical steroids twice daily until symptoms resolve. We hope to make physicians more aware of MC, the associated “molluscum dermatitis,” and treatment options.
Further reading:
- Coloe J, Burkhart CN, Morrell DS. Molluscum contagiosum: What’s new and true? Pediatr Ann. 2009 Jun;38(6):321-5.
- Hanna D, Hatami A, Powell J, Marcoux D, Maari C, Savard P, Thibeault H, McCuaig C. A prospective randomized trial comparing the efficacy and adverse effects of four recognized treatments of molluscum contagiosum in children. Pediatr Dermatol. 2006 Nov-Dec;23(6):574-9.
- Kipping HF. Molluscum dermatitis. Arch Dermatol. 1971 Jan;103(1):106-7.
- Mathes EF, Frieden IJ. Treatment of molluscum contagiosum with cantharidin: A practical approach. Pediatr Ann. 2010 Mar;39(3):124-8, 130.
- Rockoff AS. Molluscum dermatitis. J Pediatr. 1978 Jun;92(6):945-7.