Photo Rounds

Bumps on arms

A 6-year-old girl was brought to her family physician (FP) by her mother because of bumps on her arms that had developed 2 months earlier. The FP had previously treated the child for atopic dermatitis, and the mother said that the child's skin had been doing well with daily emollients and the occasional application of topical steroids. The mother said that the child occasionally scratched the new lesions.

What's your diagnosis?


The FP diagnosed molluscum contagiosum because a few of the papules had central umbilication. While she noticed that many papules did not have central umbilication, she was aware that not all molluscum lesions would have this feature. Pearly papules are classic for molluscum, even when central umbilication is not visible.

Children with atopic dermatitis are more prone to molluscum infections and frequently get them in areas that have been, or presently are, involved with atopic dermatitis. In this case, the child had antecubital involvement with her atopic dermatitis (although her skin was relatively normal at the time). The altered barrier function found in atopic individuals makes them more prone to various viral and bacterial super infections, including molluscum, herpes, and bacterial impetigo.

In immunocompetent patients, lesions usually spontaneously resolve within 8 to 12 months. In a minority of cases, disease persists for a few years. Children do not have to be kept out of day care or school for this condition, even though it is somewhat contagious. Like warts, keeping kids out of school or day care is not useful to prevent the spread of disease and is not practical on a societal level.

The FP discussed cryotherapy with the mother and child, but the girl was not willing to allow it due to her fear of the pain. Other options included watch and wait, topical salicylic acid, tretinoin, and imiquimod—although none of these have been approved by the Food and Drug Administration. Cantharidin had also been used previously in this office, but it was not available because regulations have made it very difficult to obtain. Imiquimod is not suggested for children younger than 12; therefore, this costly medicine would not be covered by insurance.

The mother requested a prescription for tretinoin and stated that if the insurance would not cover it, she would go with over-the-counter salicylic acid. The FP wrote a prescription for 0.025% tretinoin cream to be applied daily and said to stop using it if irritation became too bothersome. Follow-up was to be done as needed, but was not completed.

Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Mayeaux, EJ. Molluscum contagiosum. In: Usatine R, Smith M, Mayeaux EJ, et al, eds. Color Atlas of Family Medicine. 2nd ed. New York, NY: McGraw-Hill; 2013:743-748.

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