ANSWER
The correct answer is vitiligo (choice “b”).
DISCUSSION
Vitiligo develops when pigment cells (melanocytes) fail or die. Although there appears to be a hereditary component in some cases, as well as a connection to autoimmune disease, environmental factors (eg, intense sun exposure, stress) may also play a role.
This patient has nonsegmental vitiligo (NSV), the most common form. It is usually symmetrically distributed on high-friction areas, such as hands, knees, and elbows, as well as around the eyes and mouth. Segmental vitiligo, which affects only 10% of all vitiligo patients, tends to manifest during adolescence and typically remains confined to one area.
Unfortunately, for the majority of those with NSV (including the case patient), the condition tends to be progressive—and it responds poorly to treatment with topical steroids, calcineurin inhibitors, or phototherapy. As seen in this case, it can cause pigment loss in or around lesions; in fact, if left alone, the lesion may completely lose color. And NSV can encompass wider areas of involvement—to the extent that some patients lose all the pigment in their bodies. The resulting psychiatric fallout is considerable, especially in darker-skinned patients.
This patient's lesion will likely double in size by adulthood, which will not only subject him to ridicule but also increase the risk for malignant transformation. For this reason, he was advised to have the lesion excised under general anesthesia. He was also started on a regimen of a topical steroid cream and a calcineurin inhibitor on alternating days, but his prognosis is, in all honesty, poor.