A three-year-old boy presented with hair loss that started as a small patch on the back of his head, then spread to the bilateral temporal and parietal areas over the previous two months. The patient had no other symptoms such as rash, pruritus, or skin discoloration. According to his mother, the patient did not pull his hair out and had no history of scalp trauma. He had no history of skin or hair conditions. His only significant medical history was a leg fracture earlier in the year that did not require surgery or casting and healed without complications.

The child was growing well and was in the 50th percentile for height and weight. He met all developmental milestones. Patchy hair loss was evident in the occipital, temporal, and parietal areas of the scalp (Figure 1). The skin in the affected areas appeared normal and was smooth and nontender to the touch. Dermatoscopy revealed tiny black dots in the affected areas.

Question

Based on the patient’s history and physical examination findings, which one of the following is the most likely diagnosis?

• A. Alopecia areata.

• B. Hypothyroidism.

• C. Iron deficiency anemia.

• D. Telogen effluvium.

• E. Trichotillomania.