A patient with alopecia is experiencing which of the following conditions?

Alopecia refers to the condition characterized by hair loss, which can occur on the scalp or other areas of the body. This condition can manifest in various forms, such as alopecia areata (patchy hair loss) or totalis (complete loss of hair on the scalp). Therefore, when assessing a patient with alopecia, the primary symptom observed is indeed hair loss.

Considering the other options, excessive body hair pertains to hirsutism, which is unrelated to alopecia, and thus does not apply to this condition. Dry, white flakes from the scalp are typically indicative of dandruff or seborrheic dermatitis and would not be a characteristic of alopecia itself. An infestation of lice, while it can cause scratching and irritation, does not correlate with the fundamental definition of alopecia, which focuses specifically on hair loss rather than infestation or other scalp issues. Consequently, the most accurate choice in relation to alopecia is hair loss.