Question 1:
A 49-year-old man presented with a two-month history of localized hair loss on his left posterior scalp. The patient first noticed hair loss two to three weeks after a thirteen-day hospitalization for acute respiratory distress syndrome secondary to a work-related inhalation injury requiring intubation and mechanical ventilation as well as extracorporeal membrane oxygenation. Adhesives were used on his scalp during the hospital stay, and he did endorse sensory loss on his left parietooccipital scalp after discharge. He denied any pain, pruritus, or previous history of hair loss. On physical exam, the patient had a 4.5 cm well-demarcated patch of non-scarring alopecia with hyperpigmentation, two pustules and a few residual hairs on left occipital scalp (Figure 1). A 4 mm punch biopsy of the involved scalp was obtained and revealed the following histopathology (Figures 2-7).
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Figure 1
Figure 2
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Figure 7
What is the best diagnosis?