The answer to this question would be: alopecia areata
In this question, there is a certain area of the scalp that didn't have any hair. The best term to this condition would be alopecia areata.
There are a few reasons why a spot of baldness can appear. It can be caused by stress that inducing autoimmune disease. Before diagnosing a patient with this you must exclude the possibility of fungal infection as it can destroy the hair and make it look bald.