ANSWER
The correct answer is that new hairs growing in to replace those lost from alopecia areata tend to be white (choice “b”). They usually regain their normal color, eventually.
DISCUSSION
Alopecia areata is an autoimmune phenomenon implying an increased tendency to develop other autoimmune diseases (eg, vitiligo [choice “a”], which can appear initially in the scalp).
This case turned out to be simple but had the potential to be far more serious. The biopsy of the dark patch showed benign seborrheic keratosis, but it was possible that another section could have demonstrated features of melanoma (choice “c”). When present, melanoma can occasionally trigger an immune response that destroys pigment cells in hair follicles, causing the hairs to lose their pigment. This is why the entire dark patch was later excised. Fortunately, the pathology report ruled out melanoma.
While it has been reported that stress can cause hair to turn gray (choice “d”), there were better (and more accurate) explanations for this patient’s presentation.
This case, though fairly straightforward, serves as a reminder that it is our job as clinicians to connect the dots to rule out worst-case scenarios.
Outcome
This patient’s hair all grew back, regaining its normal color, without any treatment.