Q. A 6-month-old boy is brought to the clinic by his mother for a rash on the scalp for the past three weeks. She reports that the child is not scratching over the rash and is otherwise healthy and happy. She has tried gently washing the scalp but without much improvement. The infant’s vitals are normal and on examination, thick, crusty, yellowish-greasy scales are observed on the vertex and frontal area of the infant's scalp. Based on this presentation, what is the most likely diagnosis?