Simon presents with alopecia areata with well-circumscribed patches of hair loss on the crown of his head. How do you respond when he asks you the cause?

In the context of alopecia areata, the most accurate response to Simon's inquiry about the cause is that it is unknown, but it is suspected to be due to an immunologic mechanism. Alopecia areata is characterized by localized patches of hair loss and is believed to result from an autoimmune response that targets the hair follicles. This autoimmune aspect indicates that the body’s immune system mistakenly attacks its own hair follicles, leading to hair loss.

Current understanding does not definitively link alopecia areata to any specific environmental triggers, hereditary factors, or stressors, although these can be associated with the condition in some cases. However, the robust evidence points towards an immune-mediated process rather than a straightforward cause-and-effect relationship with external factors. Therefore, acknowledging the unknown origins while emphasizing the suspected immunologic underpinnings provides a clear and medically sound explanation for Simon's condition.