Studies have shown that common melanocytic nevi (CMN) prevalence and melanoma risk both correlate with sun exposure. Both decrease with various forms of sun protection. For that reason, CMN counts have been used as a way to both assess sun exposure, and by extension malignancy risk, as well as the efficacy of interventions aimed at increasing the use of sun protective measures.

However, manually counting CMN takes a great deal of time and access to specialists. Researchers in Sweden wanted to see if a simple app-based telemedicine platform could be used to improve access to risk screening. They developed a study that compared a dermatologist’s assessment of CMN counts in children in person to one done using a photo taken by an iPhone.

Ninety-seven children (ages 7 to 16) were assessed in person and had a photo of their backs taken. A small sticker with a millimeter scale was placed adjacent to an approximately 2 mm nevus on each patient’s back. These were used as “index nevi” for scale. The photos, taken by an app called Dermicus on an iPhone 4S, were each assessed by two other dermatologists. All three doctors marked their findings on an anatomic paper chart.


The results showed that the iPhone photos could legitimately be used to evaluate risk due to sun exposure. Both the inter-method (in-person versus iPhone) and inter-rater reliability (iPhone versus iPhone) were substantial for number of nevi counted. When the data was stratified into different nevus sizes, the results ranged from fair to substantial.

As a method of sun exposure assessment, the investigators cite prior studies showing that the number of nevi correlates well with cumulative sun exposure before the age of 10. Therefore, the data in this study demonstrates that the remote analysis using an iPhone photo is sufficient for a dermatologist to assess sun exposure.

The app used in this study was designed to allow primary care providers to send photos to dermatologists (with precautions taken to protect confidential information). Ostensibly, this would allow greater access to specialists in rural areas where they are not available, but the real benefit of this study is that it shows an app can be used to monitor dermatologic changes in a patient. More studies like this one need to be done to validate the use of mobile technology in medical practice.

Sources: Acta Dermato Venereologica, Lancet, Gnosco