Alarm Reaction of Pilosebaceous Apparatus

The document described a series of histologic changes in the pilosebaceous structures termed as an "alarm reaction." This reaction was characterized by the regression of the hair matrix, leading to the formation of a nest of small basaloid cells within the follicular canal. Additionally, the sebaceous glands either became undifferentiated, forming a solid mass of stratified squamous epithelium, or the sebaceous lobules were incorporated into the follicular canal and surface keratin layer.